The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 1
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 2
Contents
S.No Chapter Page
01 Introduction 05
02 Nutrients 11
03 Feeding Guidelines and Rations 17
04 Horse Diseases Related to Nutrition 21
05 Feeding Cost Estimation 41
06 Appendix 42
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 3
Preface
This monograph of “The Basics of Equine Nutrition and Feeding Suggestions for Horses” is compiled on the internet base study material and provided to guide the Horse owners about the Equine Nutrition to give the Balance Ration and to protect their specie from various diseases and health problems related to Nutrition. Ration and Health problems related to the nutrition are also presented in this document. It is hoped that it will provide service to the Horse owners. I am well aware that some errors and inaccuracies may have found into the text and hope that the users of this document will bring these to my attention so that to make corrections in the next editions.
Thanks!
Dr Atiq Ullah Khan Sa’yem
DVM (GCVS) RVMP (PVMC) Pakistan
http//www.dratiqullahkhan.yolasite.com [email protected]
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 4
Dedication
This Monograph is dedicated to my wonderful parents, who
have raised me to be the person I am today.
Hi Abba and Ammi!
You have been with me every step of the way, through good
times and bad. I thank you for all the unconditional love,
guidance, and support that you have always given to me, helping
me to succeed, and instilling in me the confidence that I am
capable of doing anything I put my mind to.
Thank you for everything.
I love you!
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 5
A WELL-FED, HEALTHY HORSE will be content and alert, have a keen appetite, and will have a sleek, lustrous
coat. About 75 percent of the cost of raising horses (aside from purchase of breeding stock) is feed. Overfeeding can
be wasteful and expensive, and underfeeding or a nutritional deficiency will not permit optimum performance. Since
horses depend so much on their wind, feeds should be clean and free of mold and excessive dust. In order for a horse
to be in the best possible condition, observe the following feeding practices.
Feed a balanced ration. The term "ration" denotes feed for a 24-hour period.
Accustom horses to feed gradually. In general, they may be given as much hay as they will eat. It is safe to
start horses on 1/2 pound of grain daily for each hundred pound's of the animal's weight. Thereafter, 1/2
pound of grain added to the total ration every third day is advisable. Of course, as the grain ration is
increased, roughage consumption will decline.
Feed horses regularly. In warm weather, early and late feeding during the cooler hours is preferred.
Feed two or three times daily. Usually feed grain before roughage.
Avoid sudden or abrupt changes in types of rations. Horses can go off feed.
Keep troughs and water containers clean.
Exercise horses every day.
Be sure your horse's teeth are sound.
Equine Digestive Tract Structure and Function A horse has the same requirements for energy, protein, vitamins and minerals as other animals but differs in the type
and function of its digestive system, falling between a ruminant and non ruminant.
Non ruminants (humans, pigs and dogs) digest carbohydrates, protein and fat by enzymatic action. Ruminants
(cattle, sheep and deer) use bacteria in the fore stomachs to digest fiber by fermentation and use enzymatic digestion
in the small intestines.
In the horse, all true digestion is by enzymatic digestion and takes place in the fore gut ahead of the cecum. This
accounts for 52-58% of the crude protein digestion and virtually all soluble carbohydrate digestion (fiber excluded).
(1) In addition, bacterial or microbial digestion of fibre occurs in the cecum and colon where large quantities of
volatile fatty acids are produced through fermentation and are subsequently absorbed. This dual system allows the
horse to digest simple carbohydrate sources such as starch from grain in the fore gut. Fibrous sources such as oat
hulls, soy hulls, beet pulp, hay and pasture are digested in the hind gut.
For enzymatic and microbial action to digest feed efficiently, the horse needs healthy teeth to grind feed and allow
enzymes and bacteria to attack the plant cell walls. Teeth should be examined during the annual health check to
ensure that they are wearing normally and are effectively grinding the feed.
The capacity of the stomach of the horse is only about 8-15 litres (eight quarts or two gallons), which makes it
difficult to understand how a horse can consume large amounts of food or water. The emptying time of the stomach
after filling can be about 12 minutes, and the rate of passage down the small intestine is about 1 ft/min. The net
result is that food can go from the mouth to the cecum in about 1½ hours. The small volume of the stomach and
rapid passage of food from the stomach is the reason horses eat almost continuously, thus the name "hay burners."
The rate of passage of pelleted or wafered hay is faster than for loose hay. Various studies on total passage time,
indicate two to three days is required from when food is ingested until it is passed in the manure. The mature horse's
large intestine makes up more than half of the total volume of the digestive tract, is important for microbial digestion
of food and is a major reservoir for water.
The foal and growing horse have undeveloped cecal and colonic digestion as compared to the adult horse. There is
very little microbial digestion before three months of age. Therefore, the foal requires a diet low in fibre and easily
digested in the fore gut. Foals who are seen eating their mothers manure are thought to be obtaining a bacterial
culture necessary for future microbial digestion.
Feed Intake Horses normally consume 2 to 2.5% of their body weight in dry matter daily. However, it has been estimated that
horses on pasture 24 hours a day, can consume up to 3.3% of their body weight in dry matter. As the dry matter and
nutrient proportion derived from grain increases, horses will reduce their total dry matter intake. In addition, abrupt
incorporation of grain into a horse's diet will increase the lactate concentration and lower the cecal and colonic pH
from 6.7 to 6.3. This was evident when the grain content of the ration was greater than 30% of the dry matter intake.
(2) Abrupt feeding changes, such as giving horses an extra proportion of grain prior to an event, can result in
significant accumulation of feed related lactic acid.
Chapter # 01 Introduction
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 6
Recommendations: Horses are herbivores and should receive a minimum of 50% of their dry matter intake from good quality
forage (e.g. hay, pasture).
Make changes in feed slowly over a period of 7-14 days and be careful about "topping the horses up" with
grain prior to an event.
Don't expect foals and growing horses to obtain all of their nutrient requirements from hay.
Provide clean, fresh water at all times.
Have your veterinarian examine your horses' teeth at the annual health visit.
Basic Understanding of the Horse Digestive System & Equine Digestion Enhancement
Strategies: Digestion is the process where feedstuffs that the horse consumes is broken down and converted to its simplest form
so nutrients can be absorbed into the bloodstream. These nutrients provide fats, carbohydrates, vitamins, minerals,
and amino acids (protein) required for growth and maintenance, or they can be stored until needed later. The
digestive process in the horse primarily involved enzymatic action and fermentation. For you to feed your horse to
its full potential, a basic knowledge of the digestive system is important. This information is based on a typical
1000-pound horse, but would be accurate for horses of any size and breed from miniature horses up to the draft
breeds. Only the size and capacities of the various parts would differ.
There are many different types of digestive systems used in animals. A horse is classified and a non-ruminate
herbivore and differs substantially from both humans and ruminates, such as cattle. The digestive system uses both
high levels of enzymatic action in the small intestine and high rates of microbial fermentation in the large intestine.
A horse functions best by grazing, eating small amounts of roughage products over an extended period of time. In
fact, research has shown that pastured horses will spend about 70% of their time eating. The other 30% will be spent
sleeping and socializing.
The digestive tract starts at the mouth and continues through the pharynx, esophagus, stomach, small intestine,
cecum, large colon, small colon and ends at the rectum. Associated organs that aid in the total digestive process are
the salivary glands, liver, and pancreas. The total digestive tract length is about 100 feet long that abruptly changes
in diameter and is lined by mucous membranes along the way mostly excreting digestive fluids. The digestive tract
also requires movement by the horse to help the various muscles mix and move digestive tract material. Research
has shown that stall bound horses without much freedom of movement are more prone to impaction colic.
The digestive process begins in the mouth where teeth reduce the particle size. The lips are extremely nimble and
can select specific plants, small particles of feed, and sort stones and pebbles from what they graze and eat. The
incisors sheer the plant stalk and the molars grind to the appropriate size. The chewing process stimulates the flow
of saliva, which lubricates the feed prior to swallowing. Geriatric horses who have depressed saliva glands or horses
who are aggressive eaters and often do not chew their food long enough are prone to choke. Steps such as wetting
the feed or slowing down consumption need to be considered with these horses. If a horse does choke, the esophagus
and trachea are two separate tubes down the throat, so suffocation is not an immediate threat. Do not allow the horse
to eat or drink and a vet does need to be consulted to clear the choke to avoid any potential aspiration of other feed
or liquid into the lungs.
Once the horse swallows, the feed enters a simple stomach that is relatively small (8 to 19 quarts) and has an acidy
pH. Stomach retention time is relatively small before passing into the small intestine. The small intestine is about 70
feet long, relatively small in diameter, and holds about 65 to 70 quarts. The pH in the small intestine and the rest of
the digestive system is pretty neutral. The stomach and small intestine are primarily responsible for digesting and
absorbing most of the starch, protein, fat, fat-soluble vitamins (A, D, and E), and most of the minerals. The starch
(soluble carbohydrate) absorbed here is converted into glucose and used as energy or stored as glycogen to be used
later.
Material not digested in the stomach or small intestine pass into the cecum, large colon, and small colon know
collectively as the large intestine or hindgut. The large intestine is very large and holds from 21 to 24 gallons of
liquid and feed material. This is the primary site for fiber digestion. Since the horse does not have any natural
enzymes for digesting plant fiber, the large intestine contains billions of bacteria responsible for fermenting the fiber
into energy (volatile fatty acids) and micronutrients B vitamins and Vitamin K) the horse can use. One of the
primary volatile fatty acids is proprionic acid, which is also commonly used as a preservative in feed to prevent
mold. The large intestine is also the primary site for phosphorus absorption, important for skeletal growth, muscle
contraction, and energy utilization.
The large intestine is actually the main engine of the horse and is essential to the overall health of the animal.
Without maintaining a healthy hindgut, significant problems such as colic and laminitis can easily occur. Also, since
the large intestine is responsible for synthesizing and absorbing B vitamins, including biotin, the health of the
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 7
hindgut has a big influence on things you would not normally attribute to fiber digestion such as appetite stimulation
and hoof and hair quality. Things you can do to help maintain hindgut integrity are:
Do not overfeed grain. Excess grain that does not get digested in the small intestine passes into the large
intestine and ferments extremely well. The excess fermentation causes changes in the pH and excess gas.
Both can dramatically increase to potential for colic or laminitis (founder). A good rule of thumb is not to
feed more than 0.5% of body weight of grain in a single feeding.
Make sure clean, fresh water is available at all times at the right temperature. Dirty water or water that is
too cold in the winter or too hot in the summer will inhibit consumption. The large intestine also serves as a
large reservoir providing a reserve of electrolytes and excess water essential for cooling the body to sustain
exercise. A lack of water will reduce the water required in the reservoir and will inhibit fermentation and
material flow.
Fiber quality and quantity are primary in any horse’s diet. Poor hay quality will cause loss of weight and
hay bellies. Lack of quantity will cause an imbalance between grain and fiber and increases the potential of
colic or laminitis. Another good rule of thumb is to make sure that the fiber portion of the diet is always a
minimum of 50% of the total or diet or a minimum of 1% of body weight.
Reduce rapid fiber changes. Everyone knows not to change the type of grain overnight, but the same rule
should also be followed with fiber. Ease into a new cutting or delivery of hay and gradually introduce the
horse to new spring or different pastures. Early spring pastures can have as much soluble carbohydrates and
grain.
Allow adequate turnout time. The same research that has proven that rapid fiber changes are a leading
cause of colic also indicates that lack of proper turnout is also a leading cause.
Some indications that the hindgut is not functioning very well or that other feeding options need to be considered
are:
Hay belly – indicates that poor quality forage is being provided. The large intestine will retain poor quality
forages longer trying to get as much nutrition as possible. That will stretch the large intestine causing the
hay belly appearance. Good quality forage will shrink the hindgut back to normal size.
Cow flops rather than road apples. Manure that more resembles cow manure often indicates that the
fermentation in the large intestine is not functioning optimally. This often occurs with rapid fiber changes,
excess grain, or just poor intestinal health often associated with age. Do not overlook the potential for
diseases or illnesses required the attention of a vet.
Poor hair coat or hoof condition. Typically it would accompany one or both of the problems listed above.
Research and practical experience has taught us that the healthiest horses are those that are allowed to be horses by
feeding on quality fiber on a continual basis. However, outside influences such as pasture availability, energy and
work requirements, owner life styles, and etc. have an influence on the digestive system of the horse that are not
always positive. We know a lot more today about feeding horses in the 21st century environment. Feeding for life
styles, age and living conditions are now considered when designing feeds. Even forage alternatives and improved
high fiber feeds are on the forefront of equine nutrition.
Horses, like people, are individuals. Each has their own metabolic rate and some are easy keepers while others are a
bit more of a challenge. By understanding how the internal process works, we can better understand how to feed
them to their maximum potential and limit feeding related problems.
- See more at: http://www.triplecrownfeed.com/articles/horse-digestion-equine-digestion-horsedigestion-
equinedigestion/#sthash.xWQ50eJk.dpuf
Digestive System Limitations Horses are non-ruminant herbivores (hind-gut fermentors). Their small stomach only has a capacity of 2 to 4
gallons for an average-sized 1000 lb. horse. This limits the amount of feed a horse can take in at one time. Equids
have evolved as grazers that spend about 16 hours a day grazing pasture grasses. The stomach serves to secrete
hydrochloric acid (HCl) and pepsin to begin the breakdown of food that enters the stomach. Horses are unable to
regurgitate food, so if they overeat or eat something poisonous vomiting is not an option. Horses are also unique
in that they do not have a gall bladder. This makes high fat diets hard to digest and utilize. Horses can digest up to
20 % fat in their diet, but it takes a span of 3 to 4 weeks for them to adjust. Normal horse rations contain only 3 to
4 % fat. The horse’s small intestine is 50 to 70 feet long and holds 10 to 23 gallons. Most of the nutrients (protein,
some carbohydrates and fat) are digested in the small intestine. Most of the vitamins and minerals are also
absorbed here. Most liquids are passed to the cecum, which is 3 to 4 feet long and holds 7 to 8 gallons.
Detoxification of toxic substances occurs in the cecum. It also contains bacteria and protozoa that pass the small
intestine to digest fiber and any soluble carbohydrates. The large colon, small colon, and rectum make up the large
intestine. The large colon is 10 to 12 feet long, and holds 14 to 16 gallons. It consists of four parts: right ventral
colon, sternal flexure to left ventral colon, pelvic flexure to left dorsal colon, and diaphragmatic flexure to the
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 8
right dorsal colon. The sternal and diaphragmatic flexures are a common place for impaction. The small colon
leads to the rectum. It is 10 feet long and holds only 5 gallons of material.
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 9
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 10
Colic In the mature horse, the exit and entrance to the cecum (blind gut with a capacity
of about 28-36 litres or approximately 7-9 gallons) are separated by only about 2
inches. This creates a certain amount of difficulty due to the two-way movement of
feed in this region. As a result, the cecum can be a site of colic, which may develop
when a horse is shifted from a poor quality ration to one which is rapidly digested.
Bacteria which are best at digesting high fibre type diets will be replaced with a
population of bacteria which are more suited to convert high quality and easily
digested fibre to soluble products. As easily digested hay enters the cecum,
microbial populations flourish and there is an increase in fermentation rate. The
coarse roughage will cause a relative occlusion at the exit of the cecum and will
result in gas accumulation and the pain associated with colic. This is the principle
behind the recommendation that "a horse should be shifted from one type of feed
to another over a period of one to two weeks."
Impaction of the cecum and colon is common and results from the ingestion of
poorly digestible material. This, coupled with inadequate water intake or exercise,
will predispose horses to impaction. To prevent impactions, a similar one to two
weeks should be allowed for conversion from a high quality, easily digested, ration
to one of low digestibility. This allows time for the gastrointestinal micro flora to
adjust to new substrates. Very low quality roughages should not be fed since they
predispose to impactions.
Laminitis Young lush fast-growing plants are low in fibre, can contain 22-25% protein and
equally large amounts of highly digestible carbohydrates. Sudden switches
between different feed qualities result in rapid changes to the bacterial flora and the
sudden death of the less favoured bacteria. Death of large numbers of bacteria will,
in turn, lead to the release of large amounts of endotoxin from the bacteria. Horses
placed directly on pasture after being fed hay all winter may develop laminitis due
to the sudden shift to a highly digestible feed. Grass founder or laminitis is the
sequella. Climatic conditions, such as high rain fall and hot weather, can also result
in the rapid growth of plants such as white clover which are high in digestible
protein and energy and low in fibre.
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 11
Nutrients
Horses require six main classes of nutrients to survive; they include water, fats, carbohydrates, protein, vitamins,
and minerals
Water:
Water is the MOST IMPORTANT nutrient; horses can’t live long without it! Always make sure there is an
adequate, clean supply of water. The average mature light horse may drink about 10 to 12 gallons of water daily
varying with the amount of work, the type of feed, and the weather. Horses should be watered regularly and
frequently. After heavy exertion, very warm or very thirsty horses should be watered lightly until they are
properly cooled. In very cold weather, water should be heated to 40 or 500 F. Horses generally drink about 2
quarts of water for every pound of hay they consume. In high temperature, hard work, or for the lactating mare
the water requirement may be 3 to 4 times the normal consumption. Signs that your horse may be water
deficient include decreased feed intake and physical activity, and signs of dehydration like dry mucous
membranes in the mouth, dry feces, and decreased capillary refill time. Possible causes of water deficiencies
include no water source, low water palatability, or accessibility (frozen or receiving or contaminated), or illness.
Energy Energy isn’t one of the six nutrients because the horse cannot physically consume energy, however, it is a
requirement for sustaining life. The most dense source of energy is fat (almost three times more than
carbohydrates or proteins); however, carbohydrates in the forms of fermentable fiber or starch are the most
common source. Horses exercising, growing, pregnant in late gestation or early lactation need increased energy
in their diet. Signs of energy deficiency include weight loss, decreased physical activity, milk production, and
growth rate. However, feeding a diet too high in energy can cause obesity increasing the risk of colic, laminitis,
and contribute to increased sweat loss and exercise intolerance. The basic ration for a horse is hay plus grain.
The amount of grain a horse needs depends on the growth or performance expected. The amount of total ration
is based on a consumption of 2-1/4 pounds of airdry fed per cwt. Thus a 1,000-pound horse would receive a
total daily ration of 22-1/2 pounds. The energy need is often expressed as total digestible nutrients (T.D.N.).
Generally grains provide more energy than hays because they analyze higher in T.D.N. and lower in crude fiber
(C.F.). Table 2 gives grain requirements for several types of horses.
Table 2. - Amount of Grain To Be Included in a Horse's Ration Per Cwt. of the Horse's Weight
Grain per cwt., lb. Work expected from the horse Grain or growth Breeding stock
None Idle mature horse Maintenance ....
.50 Light (0 to 3 hours per day) Light ....
1.00 Moderate (3 to 6 hours per day) Average Mere in drylot nursing foal
1.25 Heavy (More than 6 hours per day) Faster growth or fattening Stallion in heavy service
The table suggests that an idle mature horse weighing 1,000 pounds should receive 22-1/2 pounds of hay with no
grain while a similar horse doing heavy work or a stallion in heavy service should receive about 10 pounds of hay
and 12.5 pounds of grain daily.
It is usually sound economically to feed and grow weanlings well the first and second years because young horses
are more efficient and generally need less feed per pound of weight increase. Some horses can be safely fed more
than 1-1/4 pounds of grain per hundredweight. However, when fed heavily, care should be taken to see that horses
get plenty of exercise and do not become swollen or puffy in their legs.
Fat can be added to a feed to increase the energy density of the diet. Fat has 9 Mcal/kg of energy, which is
three-times that of any grain or carbohydrate source. Fat is normally found at 2 to 6% in most premixed feeds;
however, some higher fat feeds will contain 10 to 12% fat. See Fat Supplements section for more.
Chapter # 02 Nutrients
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 12
Carbohydrates are the main energy source used in most feeds. The main building block of carbohydrates is
glucose. Soluble carbohydrates such as starches and sugars are readily broken down to glucose in the small
intestine and absorbed. Insoluble carbohydrates such as fiber (cellulose) bypass enzymatic digestion and must
be fermented by microbes in the large intestine to release their energy sources, the volatile fatty acids. Soluble
carbohydrates are found in nearly every feed source; corn has the highest amount, then barley and oats.
Forages normally have only 6 to 8% starch but under certain conditions can have up to 30%. Sudden
ingestion of large amounts of starch or high sugar feeds can cause colic or laminitis.
Protein Protein is used in muscle development during growth or exercise. The main building blocks of protein are
amino acids. Soybean meal and alfalfa are good sources of protein that can be easily added to the diet.
Second and third cutting alfalfa can be 25 to 30% protein and can greatly impact the total dietary protein.
Most adult horses only require 8 to 10% protein in the ration; however, higher protein is important for
lactating mares and young growing foals. Signs of protein deficiency include a rough or coarse hair coat,
weight loss, and reduced growth, milk production, and performance. Excess protein can result in increased
water intake and urination, and increased sweat losses during exercise, which in turn lead to dehydration
and electrolyte imbalances. Horses need protein for muscle growth, for lactation, and for reproduction.
Protein needs are expressed as percent crude protein (C.P.) or more precisely as percent digestible protein
(D.P.) of the ration. Horsemen usually add supplemental protein such as linseed meal, soybean meal, or
other purchased protein to grass hay and grain rations. Legume hays such as alfalfa and red clover are also
good protein sources. The average ration should contain approximately 12 percent crude protein.
Two good common oilmeal protein supplements that can be added to grass hay and grains are
linseed meal (36 percent C.P.), and soybean meal (44 percent C.P. with hulls; 50 percent C.P.
without hulls). Soybean meal is more palatable and of higher quality for foals and young horses.
Other purchased protein supplements without urea can be used. In some cases peanut meal,
cottonseed meal, and safflower meal are good substitutes if they are economical. Protein needs of
various types of horses are summarized in Table 1.
Table 1. - Summary of Protien Needs for Horses
Type of Horse Percent
crude protein
(C.P.)
Percent
Digestable Protein
(D.P.)
Lb. oilmeal
or protein
equivalent
to add to grass
hay or grain
rations dailya
Mature idle 10 7.5 .5
Dry mare in early pregnancy 11 8.5 .75
Yearling or 2-year old 12 9.0 1.0
Mare in last quarter of gestation 12 9.0 1.0
Lactating mare 14b 10.0 1.5
Stallion in heavy service 14c 10.0 2.0
Foal under 6 months 14+d 10.0+ ...
aFour pounds of quality legume hays (alfalfa or clover) furnish approximately the same amount of digestible protein
as 1 pound of soybean, linseed, or cottonseed meal. b The highest amount of protein is needed during early lactation. Later the amount can be reduced.
cThe amount of protein needed depends on how heavy is the breeding service. The minimum is 14 percent.
dA very young foal may need up to 20 percent protein. At 6 months, 14 percent is sufficient
Vitamins Vitamins are fat-soluble (vitamin A, D, E, and K), or water-soluble (vitamin C, and B-complex). Horses at
maintenance usually have more than adequate amounts of vitamins in their diet if they are receiving fresh
green forage and/or premixed rations. Some cases where a horse would need a vitamin supplement include
when feeding a high-grain diet, or low-quality hay, if a horse is under stress (traveling, showing, racing,
etc.), prolonged strenuous activity, or not eating well (sick, after surgery, etc.). Most of the vitamins are
found in green, leafy forages. Vitamin D is obtained from sunlight, so only horses that are stalled for 24
hours a day need a supplement with vitamin D. Vitamin E is found in fresh green forages, however, the
amount decreases with plant maturity and is destroyed during long term storage. Horses that are under
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 13
heavy exercise or under increased levels of stress also may benefit from vitamin E supplementation.
Vitamin K and B-complex are produced by the gut microbes. Vitamin C is found in fresh vegetables and
fruits, and produced naturally by the liver. None of these are usually required in a horse’s diet. Severely
stressed horses, however, may benefit from B-complex and vitamin C supplements during the period of
stress.
Special attention should be given to a horse's needs for vitamins. Generally, green grasses and hays furnish
carotene that the horse converts to vitamin A. Vitamin A is important in maintaining the skin and epithelial
linings of the digestive, respiratory, urinary, and reproductive tracts. Vitamin D is often called the sunshine
vitamin because the sun's rays convert substances in the animal's skin and substances in sun-cured forages
into vitamin D. Vitamin D is especially important in the absorption and metabolism of calcium and
phosphorus for normal bone growth and maintenance. An average pleasure horse needs about 20,000 to
30,000 International Units (I.U.) of vitamin A and about 3,000 I.U. of vitamin D daily.
Vitamin E is often associated with improved reproduction and muscle maintenance. Green feeds, wheat
bran, and wheat germ oil are usually rich in vitamin E. Under conditions of barn confinement, drouthy
pastures, or feeding poor-quality forage, horses may not receive adequate amounts of vitamins A, D, and E.
In such cases, economical supplements of these vitamins can be mixed in the feed, injected
intramuscularly, or furnished in stabilized mineral blocks. Vitamin K, necessary for blood clotting, is
synthesized sufficiently in the body.
The necessary 13 vitamins are synthesized in the horse's cecum. Small supplemental amounts may be
beneficial under stress conditions of fast growth, intense training, heavy racing, or breeding. Spent brewers'
yeast may be an economical supplemental source of B vita mins. An economical premix of vitamins, as
listed below, can be added to grain mixtures if desired at the rate of 0.5 percent (10 pounds) per ton of the
grain mixture. Some horsemen prefer to add a small amount daily over the grain.
Vitamin Ammount per lb
of premix
A 1,000,000 I.U.
B1 (Thiamine) 1,000 mg.
B2 (Riboflavin) 1,000 mg.
B6 (Pyridoxine) 300 mg.
B12 1,500 mg.
C 10,000 I.U.
D 100,000 I.U.
E 10,000 I.U.
Choline Chloride 25,000 mg.
Folic Acid 300 mg.
Niacin 2,000 mg.
Pantothenic Acid 1,500 mg.
Minerals : Minerals are required for maintenance of body structure, fluid balance in cells (electrolytes), nerve conduction, and
muscle contraction. Only small amounts of the macro-minerals such as calcium, phosphorus, sodium, potassium,
chloride, magnesium, and sulfur are needed daily. Calcium and phosphorus are needed in a specific ratio ideally 2:1,
but never less than 1:1. Alfalfa alone can exceed a Ca:P ratio of 6:1. Sweating depletes sodium, potassium, and
chloride from the horse’s system, therefore, supplementation with electrolytes may be helpful for horses that sweat a
lot. Normally, if adult horses are consuming fresh green pasture and/or a premixed ration, they will receive proper
amounts of minerals in their diet, with the exception of sodium chloride (salt), which should always be available.
Young horses may need added calcium, phosphorus, copper, and zinc during the first year or two of life.
Common farm feeds provide minerals, but most horses need extra calcium, phosphorus, salt, and possibly
some trace minerals such as iron, copper, zinc, manganese, iodine, and selenium. The daily salt requirement
is about 2 to 3 ounces. Routinely providing free-choice salt that is trace-mineralized for horses will satisfy
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 14
both salt and trace mineral requirements with the possible exception of those for selenium. Not all trace
mineral salt formulations contain selenium; check the feed label when in doubt.
The calcium requirement varies from as little as 0.3 percent dietary calcium for fully mature horses to as
much as 0.85 percent in ,vealiling foals. The phosphorus requirement may range from 0.2 percent dietary
phosphorus for fully mature horses to 0.6 percent in weanling foals.
The calcium and phosphorus needs of mares in early lactation are approximately double those of mature
horses that are not providing milk for foals. A calcium-to-phosphorus ratio of 1:1:1 should be provided for
young horses. Older horses can usually tolerate a higher ratio, possibly one as high as 6:1. There should not
be more phosphorus than calcium in a horse's diet.
A good way to furnish supplemental minerals is to offer a freechoice mixture of equal parts of dicalcium
phosphate and trace-mineralized salt in a box protected from the weather. In formulating complete mixed
hay and grain rations, about I percent dicalcium phosphate and 0.5 percent trace-mineralized salt should be
added.
A. Forages
Forages are classified as legumes or grasses. The nutrients in the forage vary greatly with maturity of the
grasses, fertilization, management, and environmental conditions. In order to determine the nutrient content
in forage it is best to take samples and get them analyzed by a forage testing lab (contact your local County
Extension Office for testing information or see the fact sheet, FS714, Analysis of Feeds and Forages for
Horses). Legumes are usually higher in protein, calcium, and energy than grasses. They have more leaves
than grasses and require optimal growth conditions (warm weather and good soil) to produce the best
nutrients. Some legumes include clover and alfalfa. Some commonly used grasses include orchard grass,
timothy, bluegrass, and fescue. Hay is forage that has been harvested, dried, and baled before feeding to
horses. Legume hay can contain 2 to 3 times more protein and calcium than grass hay. However, it is usually
more costly. Common grass hays include timothy, brome and orchard grass. They have fine stems, seed
heads and longer leaves than legumes. They are most nutritious when cut earlier in their growth stage.
Maturity at harvest is key to quality. Second cut grass hays average 16 to 20% protein.
Appearance can be a good indicator of the amount of nutrients in the hay, however, color should not be used
as sole indicator. Moldy or dusty hay should not be fed to horses. For more information see Table 1.
Table 1. Evaluating Hay Quality
Characteristics of Good-Quality
Hay Characteristics of Poor-Quality Hay
Low moisture content (12 to 18%). Green in color.
Sweet smelling, like newly cut grass.
Free of mold and dust.
Cut before maturity. Grass hays before seed heads mature
and alfalfa cut early in bloom.
Free from weeds, poisonous plants,
trash, or foreign objects.
Damp. Too much moisture causes mold. Brown, yellow or weathered in color. Gray
or black indicates mold.
Musty, moldy or fermented odor.
Dusty and moldy hay is unacceptable.
Cut late in maturity. Mature seed heads with grass hay or alfalfa cut late in bloom.
High weed content, poisonous plants, or
animal carcasses in hay bales.
Roughage Hay is used in the ration for bulk and energy, and can be fed loose, pelleted or chopped.
While growth, work, and reproduction require that some of the ration consists of grain, nonlactating
broodmares and idle mature horses can get along satisfactorily on hay alone. On the other hand, working
horses can easily be fed too much roughage, resulting in labored breathing and lack of stamina.
Grass hays usually contain about 5 to 10 percent crude protein. However, this figure can be higher if grass
hays are harvested in early bloom.
Bromegrass is a perennial, palatable forage.
Orchard grass is a perennial, palatable forage often seeded with bromegrass.
Timothy is highly regarded but, in Illinois, it is a less-productive hay.
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 15
Prairie hay is a mixture of grasses of western or south-western origin.
Legume hays usually contain about 15 percent crude protein or more when they are cut at the one-third
bloom stage. Very green legume hays may be a little laxative and may cause more frequent urination,
however no real harm will ensue.
Alfalfa, a perennial, is hardy and productive.
Red clover, a biennial, will need reseeding after two years. Occasionally, second-cutting red clover may
cause slobbering.
Lespedeza is commonly grown in southern Illinois.
Mixed hays include grass and legumes. They offer variety and more protein than straight grass hay.
Straws are used primarily for bedding but clean oat and wheat straw can be used as a filler roughage. Oat
straw is more palatable.
Pastures Good pastures are an excellent source of nutrients. Pastures can supply the complete ration, but usually
working horses and lactating mares are fed additional grain. Foals on pasture are often creep-fed as well.
The pasture season in central Illinois begins about the first week in May and lasts until about the middle of
October. It begins about a week earlier for each 100 miles south of central Illinois and a week later for each
100 miles north of central Illinois.
Both temporary (one-season) and permanent pastures are used to provide feed for horses. An example of a
temporary pasture schedule is given below.
Season Forage Seeding time Grazing time
Spring Oats and barley Late March and April May and June
Summer Pearl millet Late April and May June until frost
Fall Wheat and rye Late August and September October and November; April
Some horsemen use sudangrass during the summer, but an occasional case of urinary cystitis infection has
been recorded from sudangrass grazing. Sudangrass is not safe for grazing immediately after frost or when
severely stunted by drouth. Cured sudangrass can be used as hay.
Mixtures of legume and grasses in permanent pasture provide variety and more forage. Bromegrass or
orchardgrass with alfalfa are suitable in most of Illinois. Fescue with lespedeza is often used in southern
Illinois, however deficient milk production and foaling problems have been reported in some mares grazing
in fescue pastures.
Establishment of a permanent pasture involves a considerable investment in money and labor. Good
management is also required. The following suggestions will help you establish and maintain a good
permanent pasture.
Test the soil fertility and add necessary limestone, phosphorus, potassium, and nitrogen.
Prepare a good seedbed.
Use recommended and adapted seeds and inoculate legumes.
Use a grass-legume mixture.
Seed at the proper time, preferably in early spring or fall.
Seed with a nurse crop. Oats are good. Remove the nurse crop early when oats are in the dough stage.
Cover the seed with 1/4 to 1/2 inch of soil.
Firm the seedbed by rolling.
Clip weeds, setting the sickle bar high.
Do not pasture the first season because horses will trample the seedlings.
To improve forage growth, topdress pastures with nitrogen in early spring (where legumes are less than 25
percent) with 50 to 70 pounds of actual N per acre.
Permanent and rotation pasture mixtures per acre for central and northern Illinois:
Alfalfa 8 lb. Alfalfa 8 lb.
Bromegrass 12 lb. Bromegrass 6 lb.
= 20 lb. Orchardgrass 6 lb.
= 20 lb.
These mixtures are very productive for both pasture and hay. The inclusion of orchardgrass with
bromegrass will furnish more grazing in midsummer when bromegrass may be semidormant. Seed
mixtures in late March or early April or in early fall, preferably before August 25.
Permanent pasture mixture per acre for southern Illinois where bromegrass and orchardgrass may not be as
productive:
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 16
Kentucky fescue (low endophyte) 14 lb.
Alfalfa or lespedeza 8 lb.
=22 lb.
B. Concentrates
Grains Oats have been the preferred grain for horses because they contain 12 percent crude protein and are more
safely fed than other grains because of their fiber or bulk. However, the price of oats often becomes
prohibitive. Sometimes they are crimped or crushed for cleaning and palatibility. Horses like variety, so
mixed grains are often fed. Other grains can be substituted for oats, but shelled corn, milo, wheat, and rye
are low in fiber or bulk and much denser than oat in volumeto-volume comparison.
Occasionally these grains can cause impaction or colic if they are fed alone or if they are eaten too fast by
greedy horses. It may be safer to mix shelled corn, milo, wheat, or rye with oats or place some baseball-
sized stones in the grain box to slow ravenous eating. Whenever one of these more dense grains is
substituted for oats, it should be substituted on a weight basis rather than a volume basis.
Barley also has hard hulls that should be processed to allow easier digestibility. It has moderate fiber and
energy content, and can be a nutritious and palatable feed for horses .Barley also has hard hulls that
should be processed to allow easier digestibility. It has moderate fiber and energy content, and can be a
nutritious and palatable feed for horses.
Shelled corn is high in energy and contains little fiber. It is better utilized by the horse when it is coarse-
cracked before feeding. Corn is generally more economical than oats and is nearly twice as high in energy
on a volume basis. Corn is the second most palatable grain for horses. It provides twice as much digestible
energy as an equal volume of oats and is low in fiber. Because it is so energy dense it is easy to over feed
corn, causing obesity. Moldy corn should never be fed—it is lethal to horses.
Ear corn or ground ear corn can be fed and it will minimize gulping the grain.
Milo needs to be crushed or cracked; otherwise it may be voided as whole grain in the manure.
Wheat is often expensive and needs cracking or crushing. Wheat and rye have a tendency to gum when
chewed and should not make up over 50 percent of the grain mix. Wheat is generally not used as a
feedstuff because of its high cost. Its small hard kernels should be processed for horses to digest. Wheat
is higher in energy than corn and best used in a grain mix because of its low palatability.
Rye is not very palatable and, like wheat, needs cracking or crushing.
Wheat bran is good as bulk. One pound a day is enough for a mature horse. A warm, soaked mash of 3 to 4
pounds of wheat bran alone or mixed with oats is an excellent idle-day feed. High levels of bran should not
be fed routinely to young, growing horses because wheat bran is relatively low in calcium but very high in
phosphorus.
Sorghum (Milo) is a small hard kernel that needs to be processed (steam flaked, crushed, etc.) for
efficient digestion and utilization by the horse. It is not palatable when used as a grain on its own,
however, it can be used in grain mixes. Like corn, sorghum is high in digestible energy and low in fiber.
Protein Supplements Soybean meal is the most common protein supplement, which averages around 44% crude protein.
The protein in soybean meal is usually a high-quality protein with the proper ratio of dietary
essential amino acids. Cottonseed meal (48% crude protein) and peanut meal (53% crude protein) are not as common for
horses as soybean meal. Brewer’s grains (the mash removed from the malt when making beer) are a byproduct of the
brewing industry. It is nutritious and palatable with about 25% crude protein and is also high in fat
(13%) and B vitamins. Fat Supplements
Vegetable oil is the most commonly used fat source in horse feeds. If adding the oil supplement as a
top dress to feed start with ¼ cup/feeding and increase to no more than 2 cups/day over the course of
2 weeks for the average size horse (1000 lbs.).
Rice bran is a newer fat supplement on the market. It is distributed by some commercial feed
dealers. It consists of about 20% crude fat, giving it an energy content of 2.9 Mcal/kg.
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 17
A. Feeding Guidelines 1. Forage is the base! Always try to feed the most forage possible then add concentrate.
2. Feed at a rate of 1.5 to 2% of the horse’s body weight (1000 lb. horse = 20 lbs.).
3. Feed by weight not volume!
** A 1 lb. scoop of Oats does not equal 1 lb. of Corn**
4. Stomachs are small so concentrates, if used, should be fed twice a day if not more with no more than
0.5% body weight per feeding.
5. To maintain body weight, most horses need only good forage, water, and a mineral block.
6. Store feed properly: it should be kept free of mold, rodents, or contamination.
7. Keep Ca:P ratios around 2 parts Ca to 1 part P.
8. Feed on a set schedule (horses are creatures of habit and are easily upset by changes in routine).
9. Change feeds gradually (horses’ stomachs cannot cope with drastic changes in feed; could cause colic).
10. When work or exercise decreases, decrease the grain.
11. Be aware of the pecking order in your horse’s pen— are they getting their feed?
12. Examine teeth at least once a year to make sure they are able to chew feed.
B. Consumption and Weight Horses can eat about 2 to 2-1/2 pounds of air-dry feeds (as grain in the bin and hay in the bale) daily per
100 pounds (cwt.) of their body weight.
In average condition, a light-legged mature mare over 14.2 hands (58 inches) will weigh approximately
1,100 pounds while mature geldings and stallions will weigh about 1,200 pounds.
Mature ponies under 46 inches will weigh from 400 to 600 pounds. Taller ponies up to 56 inches will
average 700 to 900 pounds.
Weanling horse foals will weigh from 400 to 600 pounds when 7 months old. Pony foals will weigh from
200 to 300 pounds when 7 months old.
Well-fed foals will reach about 50 to 60 percent of their mature weight during the first year and about 75
percent at the end of the second year. Horses reach maturity between four and five years of age.
C. Formulating Horse Rations Water, protein, minerals, vitamins, and energy are essential nutrients in a horse ration. Observe the
following points when formulating the ration.
Is the total quantity of the ration adequate?
Is the energy produced by the ration suitable for the work or the performance required?
Is the amount of crude protein (digestible protein) adequate?
Is the proper amount of minerals and of vitamins A and D included in the ration?
Is the ration economical but still nutritionally adequate?
D. Examples of Daily Rations Some examples of daily rations for several types of horses are given below. Modifications can be made in these
rations depending on the availability and cost of feeds.
Example A: Idle mature horse or pony Nutrient requirements.
Weight, lb Daily Ration, lb. Daily T.D.N., lb Daily D.P., lb
Horse 1,200 20 to 24 9.6 .8
Pony 800 16 to 18 6.4 .6
Ration 1:
Horse: 20 to 24 pounds mixed hay (1/3 alfalfa and 2/3 grass).
Pony: 16 pounds mixed hay.
Ration 2:
Horse: 20 to 24 pounds grass hay and 1/2 pound linseed meal or soybean meal.
Pony: 14 to 16 pounds grass hay and 1/4 pound oilmeal.
Chapter # 03 Feeding Guidelines and Rations
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 18
Example B. Mature horse or pony doing moderate work Nutrient requirements
Weight, lb Daily Ration, lb. Daily T.D.N., lb Daily D.P., lb
Horse 1,200 20 to 24 914.0 1.3
Pony 800 16 to 18 11.0 .92
Ration 1:
Horse: 15 pounds mixed hay (1/3 alfalfa and 2/3 grass) and 9 pounds oats.
Pony: 10 pounds mixed hay and 6 pounds oats.
Ration 2:
Horse: 15 pounds mixed bay (1/3 red clover and 2/3 grass), 6 pounds oats, and 3 pounds cracked corn.
Pony: 10 pounds mixed hay, 4 pounds oats, and 2 pounds cracked corn.
Ration 3:
Horse: 15 pounds grass hay, 6 pounds oats, 3 pounds cracked corn, and 1/2 pound linseed meal or soybean meal.
Pony: 10 pounds grass hay, 4 pounds oats, 2 pounds cracked corn, and 1/4 pound linseed meal or soybean meal.
Example C: Mare nursing foal Nutrient requirements.
Weight, lb. Daily ration, lb Daily T.D.N., lb. Daily D.P., lb.
Mare 1,100 20 to 22 18 1.9
Ration 1:
Pasture and 6 pounds grain. The grain might consist of 4 pounds oats, 1 pound cracked corn, and 1 pound bran.
Ration 2:
11 pounds mixed hay (1/3 alfalfa and 2/3 grass), 7 pounds oats, 3 pounds cracked corn, and 1 pound linseed meal or
soybean meal.
Ration 3:
11 pounds grass hay, 7 pounds oats, 3 pounds cracked corn, and I -1/2 pounds linseed meal or soybean meal. Foals
can be offered grain in a creep feeder.
Example D: Weaning 6 months to 1 year old Nutrient reauirements:
Weight, lb. Daily ration, lb Daily T.D.N., lb. Daily D.P., lb.
Weanling 600 12 to 14 10 to 11 1.3
Ration 1:
8 pounds mixed hay (1/3 alfalfa and 2/3 grass), 6 pounds oats, and 1/2 pound linseed meal.
Ration 2:
8 pounds grass hay, 3 pounds oats, 3 pounds cracked corn, and 1 pound soybean meal or linseed meal.
Example E: Yearling to 2-year-old horses Nutrient requirements:
Weight, lb. Daily ration, lb Daily T.D.N., lb. Daily D.P., lb.
Yearling to 2-year-old 900 18 to 20 12 1.5
Ration 1:
11 pounds mixed hay (1/3 red clover and 2/3 grass), 6 pounds oats, 3 pounds cracked corn, and 1/2 pound linseed
meal or soybean meal.
Ration 2:
11 pounds grass hay, 6 pounds oats, 3 pounds cracked corn, and I pound linseed meal or soybean meal.
Example F: Breeding stallion in moderate service Nutrient requirements:
Weight, lb. Daily ration, lb Daily T.D.N., lb. Daily D.P., lb.
Stallion 1,300 22 to 26 16 2.5
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 19
Ration 1:
12 pounds mixed hay (1/3 alfalfa and 2/3 grass), 8 pounds oats, 4 pounds cracked corn, 1 pound wheat bran, and 1
pound linseed meal.
Ration 2:
12 pounds grass hay, 8 pounds oats, 4 pounds cracked corn, 1 pound wheat bran, and 1-1/2 pounds linseed meal or
soybean meal.
Example G: Creep rations for a nursing foal A creep ration is commonly fed free choice where only foals can eat it.
Ration 1:
5 parts crimped oats, 3 parts cracked corn, and 1 part linseed pellets.
Ration 2:
8 parts crimped oats and 1 part linseed pellets.
Ration 3:
This is a formula for a highly palatable creep ration. It analyzes approximately 18 percent C.P. (13.5 percent D.P.),
70 percent T.D.N., and 8 percent C.F.
Ingredient Percent
Crimped oats 40
Cracked Corn 30
Soybean meal (50-percent) 20
Dehydrated alfalfa 4
Dried Molasses 4
Dicalcium phosphate 1
Trace-mineralized salt .5
Vitamin mixa .5
Aurofacb +
aTo furnish 5,000 I.U. of vitamin A per pound of ration plus B vitamins
bTo furnish 40 mg. of antibiotic per pound of ration.
Example H: Complete pelleted ration This formula analyzes approximately 14 percent C.P. (9.8 percent D.P.), 58 percent T.D.N., and 24 percent C.F.
Ingredient Percent
Alfalfa hay (chopped) 62
Oats 15
Cracked Corn 15
Dried Molasses 4
Soybean meal (50 percent C.P.) 2
Dicalcium phosphate 1
Trace-mineralozed salt .5
Vitamin premixa .5
aTo furnish 2,000 I.U. of vitamin A per pound of ration.
Ration Calculations A knowledge of the composition of a ration along with feed analyses (Table 3) makes it possible to calculate the
percent protein and percent energy of a ration. Research shows that the maintenance requirement of a horse is about
0.8 pound of T.D.N. per cwt. and that a pound of gain above maintenance requires about 3.63 pounds of T.D.N. per
cwt.
The percent of crude protein (C.P.) and digestible protein (D.P.) in a typical ration for an 800-pound yearling can be
calculated as in the following example. The C. P. figures are taken from Table 3.
Daily Ration of: lb. X C.P. = lb.C.P.
Oats 6 .12 .72
Corn 2 .08 .16
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 20
Alfalfa 5 .15 .75
Bromegrass 5 .05 .25
Soybean meal .75 .50 .375
Totals 18.75 2.255
Dividing the total C.P. in pounds by the total amount of the ration (2.255/18.75) gives a C.P. content of 12 percent.
The average digestion coefficient for crude protein of grain is about 75 percent and about 65 percent for the crude
protein of roughages. Taking an average of 70 percent and multiplying the C.P. figure by this amount (12 X .70), a
result of 8.4 percent for the digestible protein (D.P.) in the ration is obtained.
The percent T.D.N. in the ration can be calculated in a similar manner. The figures for percent T.D.N. in various
feeds in the following example are taken from Table 3.
Dividing the total T.D.N. in pounds by the total amount of the ration (11.52/18.75) gives a T.D.N. content of 61.4
percent.
Table 3. - Average Analyses of Some Horese Feeds on an Air-Dry Basis
Feed Total Digestable
Nutriants
(T.D.N.)
Crude
Protein
(C.P.)
Digestible
Protein
(D.P.)
Crude
Fiber
(C.F.)
percent percent percent percent
Grains
Oats 72 12 9.4 12
Shelled Corn 80 8 to 9 7 3
Brly 79 12 9 6
Milo 79 9 7 3
Ground Ear Corn 75 7.5 6 9
Wheat 82 12 10 3
Wheat Bran 70 17 13 9
Prorein oil meals
Linseed meal 75 36 31 9
Soybean meal with hulls 79 44 36 5
Soybean meal without hulls 80 50 42 0
Cottenseed meal 80 44 35 9
Peanut meal 80 50 43 5
Grass hays
Bromegrass 45 to 50 5 to 6 3 to 3.5 33
Orchard grass 45 to 50 5 to 6 3 to 3.5 33
Timothy 45 to 50 5 to 6 3 to 3.5 33
Prairie hay (western) 45 to 50 5 to 6 3 to 3.5 33
Legume hays
Alfalfa 50 to 55 15 10 33
Red clover 50 to 55 13 to 15 9 33
Mixed hays
1/3 alfalfa and 2/3 grass 50 8 to 9 5 33
Straw
Oats 40 4 1 40
Wheat 40 3 to 4 .5 to .75 40
The 800-pound yearling used in the examples requires 6.4 pounds T.D.N. for maintenance (800 lb. X 0.8 lb. per
cwt.). Subtracting 6.4 pounds from 11.52 (the T.D.N. in the ration) leaves 5.12 pounds T.D.N. available after
Daily Ration of: lb. X T.D.N. = lb.T.D.N.
Oats 6 .72 4.32
Corn 2 .80 1.60
Alfalfa 5 .50 2.50
Bromegrass 5 .50 2.50
Soybean meal .75 .80 .60
Totals 18.75 11.52
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 21
maintenance. Dividing 5.12 pounds by 3.63 pounds (the amount of T.D.N. required for I pound of gain) gives a
daily gain of 1.4 pounds for an 800-pound yearling fed the ration used in the above examples.
Horse Diseases Related to Nutrition
Nutritional Diseases of Horses: Descriptions of uncomplicated nutrient deficiencies in horses are rare. The nutrients most likely to be deficient are caloric
sources, protein, calcium, phosphorus, copper, sodium chloride, and selenium, depending on age and type of horse and
geographic area. Signs of deficiency are frequently nonspecific, and diagnosis may be complicated by deficiencies of several
nutrients simultaneously. The consequences of increased susceptibility to parasitism and bacterial infections may be
superimposed over still other clinical signs. Simple excesses are more common. Nutrients most commonly given in excess of
needs, leading to toxicity or induced deficits of other nutrients, are energy, phosphorus, iron, copper, selenium, and vitamin A.
Energy Deficiency Many nonspecific changes found in horses with nutritional deficiencies are related to caloric deficiency and can result from
inadequate intake, maldigestion, or malabsorption. In partial or complete starvation, most internal organs exhibit some atrophy.
The brain is least affected, but the size of the gonads may be strikingly decreased, and estrus may be delayed. The immune
system is adversely affected, resulting in increased risk of viral diseases. The young skeleton is extremely sensitive, and growth
slows or may completely stop. A decrease in adipose tissue is an early and conspicuous sign and is seen not only in the subcutis
but also in the mesentery; around the kidneys, uterus, and testes; and in the retroperitoneum. Low-fat content of the marrow in
the long bones is a good indicator of prolonged inanition. The ability to perform work is impaired, and endogenous nitrogen
losses increase as muscle proteins are metabolized for energy.
Energy Excess Overfeeding of high-calorie feeds results in obesity in horses and may contribute to developmental orthopedic disease in
growing horses. Obesity increases the risk of laminitis and colic due to strangulation of the small intestine by pedunculated
mesenteric lipomas. Obese horses and ponies have decreased insulin sensitivity and reduced heat and exercise tolerance.
Protein Deficiency A deficiency of dietary protein may represent either an inadequate intake of high-quality protein or the lack of a specific
essential amino acid. The effects of deficiency are generally nonspecific, and many of the signs do not differ from the effects of
partial or total caloric restriction. In general, the horse will have poor quality hair and hoof growth, weight loss, and inappetence.
In addition, there may be decreased formation of Hgb, RBC, and plasma proteins. Milk production is decreased in lactating
mares. The following liver enzymes have shown decreased activity: pyruvic oxidase, succinoxidase, succinic acid
dehydrogenase, D-amino acid oxidase, DPN-cytochrome C reductase, and uricase. Corneal vascularization and lens degeneration
have been noted. Antibody formation is also impaired.
Mineral Deficiencies and Excesses Nutritional Secondary Hyperparathyroidism (Bighead, Bran disease)
Horses of all ages fed grass hay or pasture and supplemented with large amounts of grain-based concentrates or wheat bran are
most likely to develop relative or absolute calcium deficiencies leading to nutritional secondary hyperparathyroidism. Excess
phosphorus intake (Ca:P ratio <1.0) causes the same clinical signs. Blood concentrations of calcium do not reflect intake due to
homeostatic mechanisms, though blood inorganic phosphorus may be elevated due to mobilization of bone mineral content.
Serum alkaline phosphatase activity is usually increased, and clotting time may be prolonged slightly. Young, growing bone is
frequently rachitic and brittle. Fractures may be common and heal poorly. Swelling and softening of the facial bones and
alternating limb lameness are frequently reported. (Also see Dystrophies Associated with Calcium, Phosphorus, and Vitamin
D:Osteomalacia.)
Phosphorus Deficiency This is most likely in horses being fed poor-quality grass hay or pasture without grain. Serum inorganic phosphorus
concentrations may be decreased and serum alkaline phosphatase activity increased. Occasionally, serum calcium levels may be
increased. An insidious shifting lameness may be seen. Bone changes resemble those described for calcium deficiency. Affected
horses may start to consume large quantities of soil or exhibit other manifestations of pica before other clinical signs are
apparent.
Chapter # 04 Horse Diseases Related to Nutrition
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 22
Salt Deficiency Horses are most likely to develop signs of salt (NaCl) deficiency when worked hard in hot weather. Sweat and urinary losses are
appreciable. Horses deprived of salt tire easily, stop sweating, and exhibit muscle spasms if exercised strenuously.
Hemoconcentration and acidosis may be expected. Anorexia and pica may be evident in chronic deprivation, although these are
not specific signs of salt deficiency. In lactating mares, milk production seriously declines. Polyuria and polydipsia secondary to
renal medullary washout may be seen in prolonged deficits.
Potassium Chronic dietary deficiency of potassium results in a decreased rate of growth, anorexia, and perhaps hypokalemia. However,
most forages contain more than sufficient potassium for the average horse. Acute deficits due to sweat losses are more likely and
may cause muscle tremors, cardiac arrhythmias, and weakness. Excess potassium intake, especially if given as a bolus PO or IV,
also will induce cardiac arrhythmias such as atrial fibrillation.
Magnesium Foals fed a purified diet containing magnesium at 8 mg/kg (3.6 mg/lb) exhibited hypomagnesemia, nervousness, muscular
tremors, and ataxia followed by collapse, with increased respiratory rates, sweating, convulsive paddling, and death after a few
weeks. However, most commonly used feeds contain magnesium well in excess of the 70–100 mg/kg dry ration currently
recommended. Oversupplementation of this mineral is more likely. Though the effects of excessive magnesium intake in horses
have not been determined, based on data from other species it may cause clinical signs of calcium deficiency.
Iron Iron deficiency may be secondary to parasitism or chronic blood loss and results in microcytic, hypochromic anemia. However,
it is highly unlikely that even anemic horses are iron deficient. Iron excess interferes with copper metabolism and also causes
microcytic, hypochromic anemia. Blood transferrin concentrations are the most reliable method to determine the iron status of a
horse.
Zinc Zinc deficiency in foals causes reduced growth rate, anorexia, cutaneous lesions on the lower extremities, alopecia, decreased
blood levels of zinc, and decreased serum alkaline phosphatase activity. Excesses (>1,000 ppm) were associated with
developmental orthopedic disease in young horses. The effects of excesses or deficits of zinc have not been documented in adult
horses.
Copper An apparent relationship between low blood copper concentrations and uterine artery rupture in aged parturient mares suggests
reduced copper absorption with age or reduced ability to mobilize copper stores. Dietary deficiency may cause aortic aneurysm,
contracted tendons, and improper cartilage formation in growing foals. Excessive copper intake may interfere with selenium
and/or iron metabolism.
Selenium Selenium deficiency results in reduced serum selenium, increased AST activity, white muscle disease, and perhaps
rhabdomyolysis in working horses. Selenium excesses of as little as 5 ppm in the ration cause loss of mane and tail hairs and
sloughing of the distal portion of the hoof.
Vitamins A Vitamin A deficiency may develop if dried, poor-quality roughage is fed for a prolonged period. If body stores of vitamin A
are high, signs may not appear for several months. The deficiency is characterized by nyctalopia, lacrimation, keratinization of
the cornea, susceptibility to pneumonia, abscesses of the sublingual gland, incoordination, impaired reproduction, capricious
appetite, and progressive weakness. Hooves are frequently deformed, with the horny layer unevenly laid down and unusually
brittle. Metaplasia of the intestinal mucosa and achlorhydria have been reported. Genitourinary mucosal metaplasia may be
expected. Bone remodeling is defective. The foramina do not enlarge properly during early growth, and skeletal deformities are
evident. The latter may be seen in foals of vitamin A-deficient mares.
If sun-cured hay is consumed or the horse is exposed to sunlight, it is doubtful that a vitamin D deficiency will develop.
Prolonged confinement of young horses offered only limited amounts of sun-cured hay may result in reduced bone calcification,
stiff and swollen joints, stiffness of gait, irritability, and reduced serum calcium and phosphorus.
Signs of experimental thiamine deficiency include anorexia, weight loss, incoordination, decreased blood thiamine, and
increased blood pyruvate. At necropsy, the heart is dilated. Similar signs have been seen in bracken fern poisoning. Under
normal circumstances, the natural diet plus synthesis by microorganisms in the gut probably meet the need for thiamine.
However, needs may be increased by stress.
Although natural feeds plus synthesis within the gut normally provide adequate riboflavin, limited evidence indicates an
occasional deficiency when the diet is of poor quality. The first sign of acute deficiency is catarrhal conjunctivitis in one or both
eyes, accompanied by photophobia and lacrimation. The retina, lens, and ocular fluids may deteriorate gradually and result in
impaired vision or blindness. Equine recurrent uveitis has been linked to riboflavin deficiency but may be a sequela of
leptospirosis or onchocerciasis. The normal feedstuffs of horses generally contain very little vitamin B12. However, the horse
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 23
There are many horse diseases that are affected by horse nutrition in some manner.
Diseases related to horse nutrition are split into two categories: those that are directly related to nutrition and those
that are indirectly related to nutrition.
Diseases that are directly related to nutrition are good news and bad news. They are usually pretty serious, but at the
same time, with proper management, they are also completely preventable. Some examples of problems that are
directly related to nutrition are:
Developmental Orthopedic Disease
Obesity
Nutritional Secondary Hyperparathyroidism (NSH)
Mycotoxicosis (Mycotoxin poisoning)
Diseases that are indirectly related to nutrition are a bit more complex, as modifying the horse’s diet alone usually
cannot treat or prevent these. In fact, some of these diseases are not preventable at all.
However, proper nutritional management often plays an important role in managing the problem. Some diseases that
are indirectly related to nutrition include:
HYPP
Polysaccharide Storage Myopathy (PSSM or EPSM)
Enterolithiasis (intestinal calculi)
Insulin Resistance
Then there are those horse diseases that fall into both categories...diseases that can be brought on by nutrition
conditions or completely unrelated conditions. These diseases can usually be managed to some extent by nutritional
management. Included in this category is:
Laminitis
Equine Colic
Equine Gastric Ulcer Syndrome (Equine Ulcers)
These diseases listed above are all diseases that most owners recognize as related to nutrition in one way or another.
However...
Did you know that many other diseases are also related to nutrition? Things like:
Rain Rot
Thrush
Allergies
can all be related to nutrition too! These diseases are usually caused by a compromised immune system.
Often, simply improving your horse's nutrition level can improve his immune function and as a result prevent
diseases such as these.
I've come across many horses that were diagnosed as having chronic cases of rain rot. When they were provided
with a high quality vitamin and mineral supplement they no longer dealt with the disease at all!
No owner wants to deal with horse disease, but it is part of living with horses. Learning all you can about horse
nutrition will enable you to manage or prevent a number of diseases, making you and your horse’s lives that much
easier.
Developmental Orthopedic Disease Developmental Orthopedic Disease, or DOD, refers to a number of different ailments which afflict growing horses.
The conditions include:
Angular Limb Deformities (ALD)
Physitis
Subchondral bone cysts
Osteochondrosis (OC)
Flexural Limb Deformities
can synthesize this vitamin in the gut, from which it is absorbed.
Last full review/revision July 2011 by Sarah L. Ralston, VMD, PhD, DACVN
Horse Diseases Related to Nutrition
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 24
Don't worry if you don't know what a single one of those diseases are...chances are you actually do know of them --
but you probably know their common names instead. So, let's quickly discuss them:
Angular Limb Deformities
ALD is more often known as crooked-legged foals. Foals born with this disease have legs that deviate outward or
inward from straight down. Usually the knee joint is the area where the leg is affected, though it can be in the fetlock
or hock joint as well.
The cause of ALD is very complex, but is associated with unequal growth of long bones...one side of the bone
grows faster than the other, resulting in the limb being deviated from normal. This abnormal growth occurs next to
the joint in the growth plate.
Causes of ALD include lameness (which causes abnormal weight-bearing), physitis,
excessive body growth in relation to bone/joint growth, and growth plate injury.
Treatment of ALD depends on how old the foal is, how severe the ALD is, and how
soon the ALD is diagnosed. In general, the earlier it is diagnosed, the easier it is to
treat. Strict stall rest and diet modification, as well as correct hoof trimming, is a part
of the treatment for all cases of ALD. Depending on the severity and limbs affected,
other means of treatment may include casts, splints, or surgery.
Physitis
Physitis is nothing more than swelling around the growth plate of a bone. It usually occurs in the bones of the legs,
and usually in bones that are closer to the ground.
There are a few theories about why physitis occurs, including malnutrition, faulty hoof growth, and compression of
the growth plate. Compression of the growth plate seems to be the most likely cause, as physitis is most often seen
in foals that are large for their age, grow quickly, and are top-heavy. It is most often seen in the summer when the
ground is hard and dry. It is also seen a lot when the calcium:phosphorus ratio is unbalanced.
Treatment includes reducing feed intake to reduce weight and/or growth rate. The diet also needs to be evaluated to
ensure that the calcium:phosphorus ratio is correct (for treatment purposes it should be around 1.6:1) and the amount
of protein is not excessive. Confining exercise to small areas where the footing is soft is also part of treatment, as is
ensuring that the feet are trimmed correctly and often.
Subchondral Bone Cysts
Subchondral bone cysts are small holes in the bone. They usually occur when the cartilage has excessive pressure or
stress placed on it (such as happens during quick growth).
These cysts most often occur in the stifle. Some horses respond to a conservative treatment of 4-6 months of rest and
treatment with bute. If the horse doesn't respond to this treatment, the only other option is surgery. However, since
surgery has very favorable results, sometimes it is done before the conservative treatment is attempted.
Osteochondrosis
Osteochondrosis (OC) occurs when cartilage fails to harden into bone. The more severe form of this disease is
osteochondrosis dissicans, or OCD. When the cartilage fails to harden into bone, a flap of cartilage remains on the
articular cartilage or growth plate. OC is a fairly wide-spread disease, affecting up to 30% of some breeds.
There is a "window of susceptibility" for each joint, during which the cartilage is forming into bone and can be
affected. Once this window has passed, it is almost impossible for the problem to be corrected without surgery.
However, before this window passes, it is possible for many mild cases of OC to resolve themselves over time.
Because of this, it is essential that growing foals have a balanced diet, so that a diet problem doesn't prevent the
lesions from resolving themselves.
Flexural Limb Deformities
Flexural Limb Deformities (FLD) are often more well-known as "contracted tendons." In FLD, the heel is pulled up
off the ground causing the foal to stand more on the toe instead of a flat surface of the hoof.
FLD can occur because of bad positioning in the uterus, limited exercise, overfeeding, and dietary imbalances.
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 25
Excess Energy
So, what do all of these diseases have in common? They all appear to be linked to (and possibly caused by) excess
energy intake in growing horses.
Young horses that are fed to achieve quick and excessive growth appear to be the most susceptible. It does not
appear to make a large difference what the diet is composed of...if they are fed in excess of energy requirements,
foals appear to be at a larger risk for developmental orthopedic disease.
It is thought that high levels of starches and sugars may contribute to hormonal imbalances in foals. These hormonal
imbalances then affect the insulin response, and higher levels of insulin are often found in the blood of foals
suffering from OCD. It is known that high starch/sugar diets affect the insulin response, but at this time it is
unknown (due to much conflicting data) whether or not this promotes occurrences of developmental orthopedic
disease.
So, until more research is done, it is best to conclude that diets excess in energy might promote developmental
orthopedic disease. As a result, growing horses will benefit from being fed a diet that promotes moderate growth
rates instead of fast growth rates.
Mineral Imbalances
Unlike the studies about excess energy's relation to OCD, there is clear evidence that unbalanced mineral intakes
cause OCD.
OCD can be caused by feeding a diet with an unbalanced calcium:phosphorus ratio, even if the foals have normal
weight gain.
Copper is another important mineral related to OC and physitis. Because copper is an important part of collagen
(which is an important part of the bone matrix), inadequate intakes can cause both OC and physitis.
Exercise
Exercise is a very important part of a foal's life. Exercise causes greater bone turnover and remodeling, which is a
good thing, and helps make the young horse's bones stronger. Both voluntary and enforced exercise both prevent
developmental orthopedic disease compared to foals that are kept in confinement with little or no exercise.
However, on the flip side, intensive exercise can cause developmental orthopedic disease.
Therefore, it is ideal to provide the growing foal with as much voluntary exercise as possible, and only supplement
with enforced exercise if voluntary exercise is not possible.
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 26
Nutritional Secondary Hyperparathyroidism is a bone diseasae in horses.
Anyone who owns horses and knows the tiniest bit about horse nutrition knows that the calcium:phosphorus ratio is
important to growing horses.
The main reason is that an imbalanced Ca:P ratio can cause bone diseases in growing horses...
...one of which is Nutritional Secondary Hyperparathyroidism, commonly abbreviated NSH.
NSH is caused by diets that contain too much phosphorus or not enough calcium.
This can be caused simply by a calcium deficiency, or it can be caused by excess phosphorus in the diet. Not only
does excess phosphorus in the diet change the Ca:P ratio, but an excess in phosphorus can actually create a
calcium deficiency by hindering calcium absorption.
Symptoms of NSH
Nutritional Secondary Hyperparathyroidism can easily go unnoticed in the early stages, due to its general symptoms.
The two earliest signs of this disease are a shifting lameness and tender joints. However, since this disease often
affects horses anywhere from weaning to 7 years of age, these first two symptoms can easily be attributed to the
horse's training or exercise regimen.
Because of this, it is sometimes hard to catch this disease in its early stages.
However, the next two symptoms, reluctance to move and a stiff gait are usually serious enough symptoms to
warrant a call to the vet in the eyes of most owners. Therefore, when these symptoms appear, the horse is more
likely to get early treatment.
All the symptoms of NSH are caused by the bone losing its mineral content, and as a result, tiny fractures occurring
in the bone.
This eventually leads to a loss of bone integrity, and a cartilage disruption, which eventually leads to tearing and/or
detachment of tendons and ligaments.
As the minerals in the bone are replaced with fibrous tissue, the bones thicken, and a physical distortion occurs.
Because the facial bones are most often affected with this disease, it has been termed "big head" in the past.
In the early 1900's when it was most prevalent, Nutritional Secondary Hyperparathyroidism was often called "bran
disease" or "miller's disease" because horses that consumed large amounts of bran by-products, particularly that of
wheat bran, were most often afflicted.
When the facial bones are affected, the horse often has trouble breathing, which is what usually warrants the
veterinary call that leads to eventual diagnosis.
As NSH progresses in the facial bones, the horse will eventually have trouble chewing as well as dental pain. This
will lead to a decreased intake of food, which will eventually result in weight loss and a poor body condition.
What kind of diet causes it?
The most common equine diet that results in Nutritional Secondary Hyperparathyroidism is the diet that consists of
mature grass forage (hay or pasture) and large amounts of cereal grain-based supplements.
These diets are often borderline or low in calcium and borderline or high in phosphorus. This is because most
grasses, though they vary in calcium content, often have a Ca:P ratio around 2:1, compared to 4:1 for legume
forages.
Compounding the problem in these diets are the cereal grains, which are extremely low in calcium, while being very
high in phosphorus. Most cereal grains have a Ca:P ratio of 1:6 or higher!
Unfortunately for most horses, this diet is still very common in today's horse population. Many horses receive grass
hay as their forage and then corn or oats, or some combination of both as their grain.
Fortified commercial products usually do not have this issue, as they contain added calcium for the most part, but it
is still something to keep in mind if you are feeding large amounts of cereal grains (more than 4-5 pounds/day).
Diets that are heavily supplemented with wheat bran or rice bran can also cause NSH. However, there are fortified
rice brans available on the market today that contain added calcium to keep the ratio where it should be.
How is it treated and prevented?
The good news about NSH is that it is easy to treat. The diet must simply be altered to provide more calcium while
reducing the phosphorus so that a correct Ca:P ratio is reached.
For early treatment of the disease, a diet with Ca:P ratios ranging from 3:1 to 6:1 has been advocated.
Nutritional Secondary Hyperparathyroidism
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 27
In older horses that contract the disease, the prognosis is very good. The bony changes will take a few months to
reverse, and some slight facial distortion may be permanent, but they will usually not have lifelong problems
resulting from the disease.
However, in younger horses, this disease is much more serious, because their bones are still growing. This disease
can cause serious problems to the long bones, and how serious the problems are depends on if the horse will suffer
lifelong problems as a result of the disease.
The easiest and most effective way to prevent this disease is to ensure that your horses receive a diet that has a
balanced Ca:P ratio, particularly if there are growing horses in your herd.
Just as essential is to ensure that the horses have enough calcium, as that can cause problems even if the Ca:P ratio is
correct.
Mycotoxicosis is the disease caused by ingestion of mycotoxins, which are toxins produced by fungi living on or in
a plant at harvest time. This disease is very serious because of the possible severe reactions (including death in some
cases) in horses. Thankfully, it is also a fairly rare disease.
Some of these toxins are fatal within hours of ingestion, such as ergotamine, produced from ergots from the fungi
Claviceps spp. This fungi has been found contaminating fresh pasture in Europe.
Other mycotoxins, however, do not have such serious
consequences of ingestion. These include slaframine,
produced by Rhizoctonia leguminicola which is found
in red clover and alfalfa. This mycotoxin causes
excessive salivation and increased water intake.
However, it breaks down in stored forages over time,
so its less likely to cause problems.
The biggest problem, from a management standpoint,
is the fact that there are no reliable predictors of
mycotoxin infestation. A number of plant variables,
such as plant health, growth status, and plant maturity
all affect whether or not mycotoxicosis is a potential
problem.
Conditions at harvest, including weather and how quickly the feed is stabilized also play a major role.
Temperature and moisture content at harvest time, as well as during storage, are two of the biggest indicators of
whether or not mycotoxicosis might be a problem.
However, the various temperature and moisture combinations at which the different fungi produce harmful levels of
mycotoxins is largely unknown. Complicating the matter even further is the fact that there are so many various fungi
that produce mycotoxins, creating a wider range of conditions under which problems may occur.
Mycotoxins can be found in fresh pasture, stored forage, or grains. The fungi need heat and moisture to thrive and
produce the toxins, so mycotoxins will usually not be found in feeds that have been properly harvested and stored.
This is one reason it is so important to only feed your horse feeds that you know have been properly harvested and
stored. When in doubt, don't feed!
Below is a table that summarizes some of the various fungi and their toxins. Don't be alarmed by the size of the
table...like I mentioned above, mycotoxicosis is a pretty rare disease, despite the various organisms and plants
involved.
Fungus Family Specific
Fungus
Source Specific Plant Toxin Toxin Symptoms
Claviceps spp. Pasture Ryegrass;
Canarygrass;
Dallisgrass;
Native European
species
Toxic
alkaloids
Mycotoxicosis and Mycotoxins:
How do they affect YOUR horse?
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 28
Rhizoctonia
spp.
Pasture
Hay
R. leguminicola Pasture
Hay
Red Clover;
Alfalfa
slaframine Excessive salivation;
Increased water
consumption
Fusarium spp. Pasture
Hay
Silage
tricothicenes Kidney damage;
Nervous system problems
fumonisins Blind staggers;
Death
F. roseum;
F. graminearum
zearalenone
vomitoxin
Reproduction problems
Asperigillus
spp.
Hay
Silage
aflatoxins Carcinogenic;
Liver problems
Penicillium
spp.
Hay
Silage
dicoumerol Nasal bleeding;
Joint Swelling;
Lameness;
Respiratory problems
patulin Carcinogenic
Like most diseases that face our horses today, mycotoxicosis is much more easily prevented than treated. Use
common sense when buying feed products for your horse, especially hays. Ask the producer how it was stored and
what the weather and drying conditions were when it came out of the field.
Store feeds properly yourself...keep them off the ground and in a place where they won't get rained on or other
moisture drawn into them. I personally also salt my hay bales for extra protection, giving me one less thing to worry
about.
Hyperkalemic periodic paralysis, better known in the horse world as HYPP, can be a devastating disease. There are
horses that have it that never show a symptom a day in their life, and horses that have repeated severe episodes, to
the point that their owners choose to humanely euthanize them instead of watching them suffer.
A large part of the management of hyperkalemic periodic paralysis is based around the diet, so we are going to
discuss today what aspects of the HYPP horse's diet are most important.
However, to understand how this diet helps the HYPP-positive horse, its essential to understand how this disease
works, and what it does to the horse.
HYPP: The Genes Behind It
In big words, hyperkalemic periodic paralysis is a co-
dominant single autosomal gene disorder. In easier-to-
understand language, this means that:
It's genetic
It is located on one single autosomal gene
It is co-dominant
(more on these last two in a minute!)
Now for a very basic genetic lesson:
Hyperkalemic Periodic Paralysis (HYPP)
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 29
Genes are made up of parts called "alleles"...each horse has one from its sire and one from its dam for each gene.
So, in respect to hyperkalemic periodic paralysis, a horse could be N/N, which is two normal alleles on the
gene...this horse would not have HYPP, and could not possibly pass it on to its foals. These horses are HYPP
negative.
Or, the horse could be N/H...this is where the co-dominance comes in. In a gene that is not co-dominant, either the
animal has the disease, or he doesn't. However, with co-dominance, there is an "intermediate" which is different
from the positive and negative.
Horses that are N/H have one affected allele, and one normal allele. They can show symptoms of the disease, but
they are less likely to show symptoms than horses that have two affected alleles. However, it can still happen, and
they CAN still pass it on to their foals.
For all intents and purposes, these horses should be treated and managed as if they have hyperkalemic periodic
paralysis. These horses are often referred to as HYPP "carriers" because they carry the disease in their genes, but
they don't always exhibit symptoms.
And lastly, horses can be H/H. These horses have two copies of the problematic allele, and are considered HYPP
positive. These horses are most prone to HYPP attacks, and need to be managed very carefully.
H/H horses will ALWAYS pass on an affected gene to their foals. This means that if they are bred to a N/N horse,
all of their foals will be N/H (carriers). If they are bred to a N/H horse, their foals will all be N/H (carriers) or H/H
(positive).
HYPP: Abnormal Muscle Cells
In a normal muscle cell, there is an electrical gradient across the cell membrane when sodium is pumped out of the
cell and potassium is pumped in. This gradient is usually around 85 millivolts (mV)
This gradient is able to be maintained because the only way sodium can get into a cell is through the sodium
channels. However, these channels are not always open. In fact, most of the time they are closed -- they are only
opened when a nerve impulse is received by the cell.
When the sodium channel is closed, sodium collects outside the cell while potassium collects inside the cell. As long
as the electrical gradient remains close to 85 mV, the cell will stay at rest and the muscle will not contract.
When a nerve impulse is received by the cell, the sodium channel changes shape and allows sodium to rush into the
cell. At the same time, potassium rushes out, because both ions are positive, so potassium moves to the more
negatively charged area, which is outside the cell.
As the sodium rushes in and potassium rushes out, the electrical gradient gets close to 0 mV. This is called an action
potential and causes calcium to be released from storage sites in the cell. The calcium then binds with areas on the
muscle fibers called myosin. Once the calcium is bound, the muscle contracts and stays contracted until the calcium
pump in the cell gets all the calcium put back into the storage site.
Then the entire process starts over again with another nerve impulse.
That is how it is supposed to work. However, in horses that have hyperkalemic periodic paralysis, the sodium
channels are "leaky". They are not able to completely close, thus sodium is constantly leaking into the cell.
All this leaking of sodium causes the electrical gradient to be repeatedly brought close to 0mV, which causes the
muscles to release the calcium and it to bind. This happens over and over, causing the muscles to repetitively
contract.
Large muscles
All of the repetitive contractions of the muscles works the muscles even when the HYPP horse is at rest. Because a
muscle grows the more it is worked, any muscles that are being affected will grow larger than normal.
However, not every HYPP positive horse has visibly large muscles. Likewise, not every horse will abnormally large
muscle groups will have HYPP. There is absolutely NO way to tell if a horse has HYPP just by looking at it.
The only way to tell for sure is to have the horse tested. UC Davis is the most well known place to have a horse
tested for HYPP...you simply send a hair sample in and they send you the results after it has been tested.
You can also tell if a horse is definitely negative if he has two parents that have been tested and are both N/N.
The Impressive Disease
Hyperkalemic Periodic Paralysis is often known as the "Impressive" disease because it is thought that the gene
mutation that causes it started with the famous Quarter Horse stallion named Impressive.
However, there are some people in the horse world that believe it may go back further than Impressive.
I've heard accounts of at least 2 horses that tested positive for Hyperkalemic Periodic Paralysis at UC Davis without
having Impressive in their pedigree. However, both mares that did test positive (UC Davis tested 3 different samples
from each mare and all came back positive) did have Impressive's dam, Glamour Bars, in their pedigree. These
mares just happened to be tested because they were part of a good-sized breeding operation that tests all of their
horses regardless of bloodlines, before sale.
There is speculation that the gene mutation goes back further in Glamour Bars' pedigree, probably carried through
the dams. This is rational, as mares usually average 10-15 foals throughout their lifetime at most, so the chances of
them having large amounts of offspring affected would be minimal. Even if half the foals from one mare carried the
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 30
disease or were afflicted by it, news about it would not spread much further than the foal's immediate locale, thus a
problem like this carried through the dam's line would probably not be caught.
Regardless of how far the HYPP mutation does go back, research has proven that it goes back to Impressive for
sure. Thus every horse that has Impressive in his pedigree has a chance of carrying the disease (unless his parents
have been tested negative) and should be tested.
Nutritional Management of HYPP
The overall goal of treatment and management of Hyperkalemic Periodic Paralysis is to limit increases in serum
potassium levels. This is done by a combination of:
Limiting dietary potassium intake
Promoting entry of potassium into cells
Eliminating excess potassium from the body through urine
The single most important aspect of treatment is limiting dietary potassium intake. If a Hyperkalemic Periodic
Paralysis-positive horse consumes a diet that is more than 1% potassium, clinical signs, or "attacks" are more
common.
However, if the diet is maintained below 1% potassium, the disease can often be managed without any other
preventative measures.
The largest source of potassium in a horse's diet is his hay. In general, grass hays tend to have less potassium than
legumes such as alfalfa. However, the potassium content of hay depends on where it was grown, when it was cut,
and conditions during growth and harvest, as well as the grass fertility and moisture content. Due to this great
variation, it is imperative that if you are managing a HYPP horse, you have your hay tested at a laboratory for
potassium content.
It is usually a good idea to maintain an HYPP horse on grass hays such as timothy, Bermudagrass, or prairie hay. If
legumes such as alfalfa must be included in the diet, it may be necessary to use other measures to control the
disease.
Inclusion of larger amounts of cereal grains in the HYPP horse's diet is also a way to decrease the potassium level,
as cereal grains are fairly low in potassium.
Not only will the intake of cereal grains decrease the potassium content of the diet, but it may also increase the
uptake of potassium into cells by promoting insulin release, which promotes uptake of potassium into cells.
However, intake of commercial mixes that contain molasses, soybean meal, or dehydrated alfalfa should be
monitored, as these feeds can contain large amounts of potassium.
Management beyond nutrition
In cases where nutritional management is not enough to control Hyperkalemic Periodic Paralysis, a few other
options are available.
Mild exercise, insulin release, and administration of other cations have all been shown to increase potassium uptake.
Insulin release can be achieved by feeding cereal grains high in starch, or administering glucose either IV or orally.
Sodium or calcium administered through IV will increase potassium uptake as they are both cations.
Another prevention method that can be used under the supervision of a veterinarian is the administration of
acetazolimide, which is a diuretic that increases the excretion of potassium in the urine.
Hyperkalemic Periodic Paralysis is a scary disease to have to deal
with. Thankfully it can usually be managed through dietary changes.
If dieatary changes are not sufficient to manage the disease, there are
other options available.
Knowledge of what the disease does, how it is passed on, and what
causes it all help you be prepared should you end up with a HYPP
positive horse in the future.
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 31
Polysaccharide Storage Myopathy is a disease that occurs when excess glycogen (storage form of glucose) or
glucose-6-phosphate (form of glucose taken into cells) is present in muscles.
Often referred to as PSSM, this disease is called equine polysaccharide storage myopathy, or EPSM, when it occurs
in draft horses.
A clinical diagnosis of PSSM can be made when a horse that suffers from chronic exertional rhabdomyolys (ER) is
found to have amylase-resistant polysaccharide in his muscles. Amylase is the enzyme that breaks starches down to
sugars. ER is a syndrome of muscle pain and cramping that is associated with exercise.
However, the build-up of amylase-resistant polysaccharide may take quite some time to build up before it can be
detected. In one study, Quarter Horse foals that showed symptoms of chronic ER did not have the amylase-resistant
polysaccharide apparent in their muscles until they were two years old!
The good news about PSSM is that its symptoms can be controlled by diet to an extent.
Signs and Symptoms
Most of the signs and symptoms of PSSM have to do with the muscles, which makes sense, as the disease affects the
muscles.
Common signs and symptoms include:
Exertional Rhabdomyolysis
Exercise Intolerance
Muscle Stiffness
Shifting Lamenss
Back Pain
Camped-out stance - standing with legs behind or in front of body instead of directly under
Muscle atrophy
Colic-like symptoms
In draft horses and other related breeds such as Warmbloods, the symptoms of EPSM appear as muscle soreness in
the back and hindquarters, stiffness, and sometimes ER.
In Belgains, EPSM may occur in conjunction with a disease known as "shivers", which shows up as muscle tremors
and over-extension of the back legs.
Controlling Symptoms with Diet
To control the symptoms of PSSM with diet, horses must be fed a diet that is low in starch and sugar and high in fat.
This type of diet has been shown to reduce the frequency and severity of symptoms.
To be helpful, the total diet must contain less than 8% of the digestible energy from starch and sugar. In addition, it
must contain more than 10% of digestible energy from fat.
Horses with PSSM must also be exercised regularly, as lack of exercise increases the frequency and severity of
symptoms. In fact, even if the diet is changed, there will usually not be a reduction in symptoms unless the horse
also receives regular exercise and turnout.
The exact recommendations for a PSSM diet are:
Feed a minimum of 1.5% body weight of forage per day
Remove all concentrates containing grain or molasses from diet
Use alternative energy sources if digestible energy needs are more what is provided by forage alone.
It is suggested that the forage provided be grass or oat hay, as these hays are lower in starch and sugar than legume
hays.
Alternative energy sources include vegetable oil, rice bran, non-molassesed beet pulp, and black oil sunflower seeds.
Some horses may need a fat content higher than 10% of the diet, so you may have to do some experimentation with
your individual horse to find the correct balance of starch and sugar content, fat content, and exercise.
Polysaccharide Storage Myopathy
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 32
Polysaccharide Storage Myopathy can be a scary disease until it is
properly managed. Knowledge of the disease allows you to manage
it through diet and exercise.
By following the recommendations of:
Adequate forage intake
No grains or molasses
Use of alternative energy sources
as well as ensuring adequate daily exercise you will be able to
successfully manage almost every case of PSSM or EPSM.
Once PSSM is managed through diet and exercise, it becomes much
less of a problem for both the horse and his owner.
Enterolithiasis is the presence of intestinal calculi, called enteroliths. These calculi are deposits, or build-up, in the
large intestine.
This is a problem, because they can cause blockages of varying degrees, usually resulting in colic to varying
degrees.
In fact, during one study, more than 15% of horses admitted to the large animal clinic at UC Davis for colic
complaints can blame enterolithiasis for the colic episode.
So what exactly are enteroliths? They are a build-up of struvite crystals, which are composed of magnesium
ammonium phosphate.
The crystals are laid down in concentric rings, and the larger the ring, the bigger the blockage. The rings usually
start around a foreign body in the intestine, such as a small piece of cloth or hair that has been ingested.
These rings can form into one large enterolith, or they can form into
numerous small enteroliths in groups.
If one large enterolith is formed, usually the horse will experience
colic to varying degrees as the calculi gets lodged in areas of the
large intestine, causing bloating and digesta back-up to varying
degrees.
However, if small enterolith groups are formed, usually the horse
will just display symptoms of mild abdominal pain, as the small
crystals usually don't cause blockages. Instead, they irritate the tract
lining as they move.
Which horses are at risk?
Like I mentioned before, in one study more than 15% of horses admitted to UC Davis for colic were suffering from
enterolithiasis. Yet, at the same time period, less than 2% of horses admitted to a clinic in Texas for colic had
enterolithiasis.
This is due to the fact that it appears horses in certain geographical regions are more prone to the disease. California
and the southeastern US appear to be the areas with the highest number of cases.
Enterolithiasis
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 33
However, horses in every geographical region can have enterolithiasis.
Breeds that tend to be over-represented include Arabians
(and Arabian crosses), Morgans, American Saddlebreds,
donkeys, and miniature breeds.
There also appears that there might be a genetic component
to the disease, as the reported occurrence in siblings is high.
It used to be thought that young horses would not suffer
from intestinal calculi due to the length of time it usually
takes the crystals to form.
However, there have been reported confirmed cases in horses less than one year of age.
This suggests that in the right conditions, it is possible for the crystals to form to a problematic size in a short
amount of time.
What causes enterolithiasis?
A number of studies have pointed to increased large intestine pH as a cause of this disease. Normal pH in the horse
large intestine is usually somewhere around 6.9, while horses with substantial enteroliths usually have a pH
somewhere around 7.3.
Affected horses also have a lower content of dry matter in their colon, as well as higher concentrations of
magnesium, phosphorus, calcium, and potassium, as well as other nutrients in the digesta.
Also, horses that are fed large amounts of alfalfa (more than 70% of
forage intake) appear to be at higher risk. This is because alfalfa has
very high buffering capacities, and buffers are used to promote a
higher pH. It also has more protein and magnesium than grass hays,
both of which are thought to contribute to the formation of the
crystals.
However, due to the large number of horses that consume large
amounts of alfalfa and do not have enteroliths, alfalfa is obviously not the only factor in causing the formation of
struvites.
One of the last risk factors for enterolithiasis is lack of daily access to pasture. It is not clear whether pastured horses
are at less risk because of increased grass intake or increased exercise, but for one reason or the other, or maybe a
combination of both, horses that have daily access to pasture are at less risk than those that are stalled for more than
50% of the day.
Nutritional Management
A diet low in magnesium, phosphorus, and protein has been shown to reduce the occurrence and size of enteroliths
in dogs in cats. Likewise, in horses it appears that dietary modifications can also be used as prevention of
enteroliths.
Dietary recommendations that increase the acidity of the colon that have been suggested include:
exclusion of alfalfa from the diet
exclusion of wheat bran from the diet
increased grain:hay ratio
supplementation with apple cider vinegar
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 34
Though these methods have all been suggested in one study or another, there is no solid evidence of how well they
increase the acidity of the colon or prevent struvite formation.
However, in lab studies, when the colon pH was below 6.6, the size and weight of enteroliths present decreased. In
another study, ponies that were supplemented with 1/2 cup apple cider vinegar daily saw a reduction in the size of
their enteroliths.
So, for horses that have experienced problems with enterolithiasis, it is recommended that grass hay (instead of
alfalfa) is fed, along with some form of grain (approximately 5 pounds/day for a 1000 pound horse) and 2 cups of
apple cider vinegar (1 cup twice a day) to help prevent future occurrences.
This is, of course, assuming the horse has no other issues that would be negatively affected this diet.
It is also recommended that horses at risk receive daily turnout, preferably in a good pasture if possible.
management affects it.
Nobody ever wants to hear that their horse has laminitis, but it happens way too often in the horse world. In fact, this
very serious disease is the second-leading killer of horses...only colic takes more equine lives each year.
What is laminitis in horses?
Equine laminitis is caused when the laminae become inflamed. In normal conditions, these soft tissues connect the
hoof wall to the coffin bone and other structures within the hoof...much like Velcro is used to fasten two things
together.
However, when the laminae become inflamed, the connections start to break, which causes catastrophic damage to
the bones and other structures within the hoof.
The inflammation also causes a constriction of blood vessels to the area, leading to ischemia, or lack of blood, to the
cells. When the cells cannot get the nutrients they need, they start to die, compounding the problems.
The Four Stages of Equine Laminitis
Developmental Laminitis This stage is the time period between the triggering event and the first appearance of lameness. This period will
usually last approximately 40 hours, and the horse will usually not show any symptoms during this period.
Common triggering events of equine laminitis include:
Over-consumption of grain or lush pasture
Prolonged high fever
Pneumonia
Potomac horse fever
Excessive stress
Unrelated lameness in another limb
Road founder or excessive prolonged concussion
Stall shavings that contain black walnut
Mastitis founder affecting lactating mares
Equine laminitis may be one of the scariest diseases in horse nutrition...at
least until you learn how to successfully manage it. The good news is that it
can be successfully managed and prevented through nutrition.
According to the 2000 National Animal Health Monitoring System, 50% of
the laminitis cases seen every year could be prevented through correct
nutritional management!
Considering that almost 5% of horses that undergo surgery for laminitis end
up dead
Equine Laminitis
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 35
Placenta retention beyond 12 hours
Colic, especially after surgery
It has been proposed (and substantiated by human medicine and limited studies in horses) that cold hosing and/or
applying ice water to affected limbs during this period may prevent the progression of the disease.
In one study1, 6 Standardbreds were dosed with oligofructose (given in amounts known from previous studies to
induce laminitis in 100% of cases).
After treatment, one front foot of each horse was placed in a rubber boot with 50% ice cubes and 50% water while
the other three feet were left untreated. For the entire 48-hours of the study, the ice was replenished to keep the level
just below the carpus.
At the end of the study period, the untreated feet on all 6 horses had clinical laminitis, ranging from mild to severe.
However, the treated feet on all 6 horses showed no signs of laminitis at all. The horses all tolerated the boots well,
and showed no ill effects from wearing them.
Because the horses were humanely euthanized at the end of the study, it is still unclear whether or not the treated
feet would eventually develop laminitis after the cold therapy was stopped.
However, the cold therapy during the developmental period of the disease clearly prevented the progression of
laminitis. Due to these results it is thought that a horse that is a suspected laminitis case will benefit from cold
therapy. Once the horse has started to show signs of pain, it is too late for the cold therapy to do any good, as the
disease has moved on to the acute phase.
Acute Laminitis The acute stage has one of two outcomes: either the horse makes it through the next 72 hours with no physical or
radiological collapse, or the horse suffers a digital collapse (rotation or sinking of the coffin bone) and the disease
moves into the chronic stage.
Subacute Laminitis If the horse does not suffer digital collapse during the acute stage, he moves inot the subacute stage which lasts for
8-12 weeks. During this stage, the horse is considered to be recovering from the damage done during the
developmental and acute stages.
Chronic Laminitis If the horse does suffer a digital collapse during the acute stage, he is considered to have chronic laminitis. Thus, any
horse that has suffered from rotation or sinking of the coffin bone is considered to have chronic laminitis, regardless
of how long he displayed signs of pain during the initial onset of the disease.
Nutritional Management of Equine Laminitis
One of the easiest ways to prevent laminitis brought on by over-consumption of grains is to properly store your feed
to ensure that the horses have no access to it. If you have smart horses in your barn, this may mean measures as
drastic as padlocking the feed room door and/or feed bins.
To prevent most cases of equine laminitis caused by over-consumption of lush pasture, ensure that horses are slowly
introduced to pasture whenever they have not had constant access to it for some time. Most generally this will be in
the spring, but can also be in the fall, if they have been removed from the pasture during a late summer drought
period.
To prevent laminitis from being triggered by an upset to the pH and digestive process in the lower digestive tract, it
has been suggested that any meal given to horses contain no more than 2-4 grams of starch per kilogram of body
weight.
For a 1000 pound horse, this means no more than 1-2 kg (2.2-4.4 pounds) of starch each meal. Therefore, if a horse
is being fed a grain product that is 30% starch (which many on the market are that or higher) that means the safe
upper limit for each meal in this respect is anywhere from 7-14 pounds.
In general, the concentrations are going to be high in spring, intermediate in autumn, and lowest in mid-summer.
However, the levels also fluctuate daily, based upon when the plant is creating and storing energy. The levels tend to
rise during the morning hours, reaching a maximum in the afternoon, before falling during the evening and
overnight hours. Therefore, the levels during the afternoon may be 2-4 times greater than the levels in the same
pasture during the morning hours and overnight hours.
Removing laminitic horses from pasture during the day and turning them out for grazing overnight will help
minimize their intake of these water-soluble carbohyrdates.
For the horse with chronic laminitis, it is prudent to keep his body weight within a desirable range. Overweight
horses bear more weight on each limb than those at an ideal weight, so keeping these horses at an ideal weight will
minimize the impact and trauma on the affected limb from daily activities.
It is also essential that these horses receive a high nutrition level so that they have adequate nutrients necessary to
repair and maintain hoof quality. For many of these horses, like Babs, a ration balancer can be an ideal solution,
providing minimal calories and high levels of nutrition.
Lush pasture is often a problem because of the water-soluble carbohydrates such as glucose, fructose, and fructan.
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 36
These substances are thought to cause problems in hind-gut fermentation similar to the problems caused by
excessive starch. These digestive problems then trigger equine laminitis.
Therefore, it is prudent to limit pasture access to horses with chronic laminitis, or at risk for laminitis, during
periods when these substances are at high concentrations.
Knowledge of equine laminitis and how to prevent it can assist you in preventing this disease in your horses.
Because it is such a devastating disease, and treatment success rates plummet so rapidly, it is essential that horse
owners treat any suspected case of equine laminitis as if it is an actual case, until it has been determined that the
hoof pain was caused by something else.
I hope that you are lucky enough to never have to deal with equine laminitis personally, but now you have more
knowledge of the disease in the event you need it.
Don't think you have to worry about equine ulcers? Does your horse suffer from any of the following??
Chronic colic
Poor body condition
Loss of or poor appetite, especially when grain is involved
Poor performance
Bad attitude while being handled and/or ridden
Generally ill tempered
Continually fluctuating body weight
If so, your horse could be suffering from Equine Gastric Ulcer Syndrome, the official term for equine ulcers. This is
a very common problem in horses, much more prevalent than many owners realize.
Some reports show as many as 85% of pleasure horses suffer from this problem. Rates for horses with stressful
lives, such as show horses or race horses have been reported to have rates higher than 95%.
Ages of Horses Affected
Equine ulcers can affect any age of horse, from newborn foal to geriatric animals. Thankfully, they can be treated by
various methods, and management practices can be altered to help prevent them.
Young Foals The condition in very young foals is known as neonatal gastric ulceration. It is usually accompanied by another
severe illness, such as generalized sepsis.
Suckling Foals In suckling foals, the condition is known as gastroduodenal ulcer disease. This form of ulcers is characterized by
ulcer in the upper digestive tract -- usually the lower esophagus, stomach, or upper part of the small intestine.
The cause is unknown, but researchers suspect the problem starts with inflammation in the small intestine. This
inflammation causes a back-up of acidic digesta, which then causes ulcers in the stomach and lower esophagus.
It is suspected that a viral or bacterial disease causes the initial problems that lead to equine ulcers in these foals.
Mature Horses The main form of equine ulcers to affect mature horses is erosion or ulceration of the squamous mucosa.
This means the protective mucous layer of the stomach and digestive tract breaks down and can no longer protect
the underlying tissue from the acidic environment. When the underlying tissue is exposed to the acid, the acid eats
away at it, much like happens to our skin when we spill acid on it.
Risk Factors
A number of risk factors can predispose a horse to equine ulcers. The most obvious is a stressful lifestyle such as
that of a show or race horse. Other factors include housing situations, feeding situations, and temperament of the
animal.
Intense Exercise Intense exercise has been shown to play a major role in the formation of ulcers.
One study of Thoroughbred racehorses showed an ulcer prevalence of 100% in horses actively racing. Horses in
race training weren't much better off, as the prevalence in that group was 91%.
A study of endurance horses showed that they had an ulcer prevalence of 67% after races.
The current speculation is that tightened abdominal muscles caused by intense exercise cause acidic digesta to back
up into the upper digestive tract and remain there longer than usual.
Equine Ulcers: Are They Causing Your Horse Problems?
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 37
Electrolyte administration Surprisingly, it has been found that routine administration of electrolytes, such as is done for endurance horses
during races, can cause the formation of equine ulcers.
In a study of 14 horses, those that received 8 hourly doses of commercial electrolytes showed a higher number of
ulcers compared to the control group. The horses that received electrolytes also had more severe ulcers than the
control group.
Confinement Housing Confinement housing, particularly in a stall, is another risk factor for developing ulcers. Horses with no prior ulcer
history who were moved from a pasture situation to stall confinement showed ulcers after only 7 days!
It has been suggested that these types of housing situations cause ulcers due to:
Lack of socialization with other horses
Changes in diet composition
Decreased meal frequency
Decreased grazing time
Temperament of Animal Temperament is also thought to play some role in ulcer formation, though it is not clear exactly how big of a role it
may play.
Nervous horses have been proven to have a higher prevalence of ulcers than their more calm counterparts.
Though we are not sure of the exact reason nervous horses are more prone to ulcers, it is currently suspected that
this higher frequency might be caused by the body being under continual stress.
Meal Composition Meal composition is thought to play a role in equine ulcer formation because of how it affects saliva production.
When a hay meal is fed to a horse, more chewing is required, and therefore more saliva (which is an important
buffer for the digestive tract) is produced. If an equal weight of grain replaced the hay meal, only half the amount of
saliva would be produced.
Saliva is also more continually passed into the digestive tract with a hay meal, since it takes the horse longer to eat
the hay meal than the grain meal. This makes a more stable lower digestive tract, because the acidity of the tract is
not able to drop dramatically.
Meal Size Meal size also plays a role in ulcer formation. Large grain meals produce more acid than an equal weight of hay
(and less saliva as mentioned above!). The large grain meal will also empty from the stomach more slowly than
small grain meals or hay.
So not only have we created more acid, we've also created a situation where it sits in the stomach for a longer period
of time. This is practically screaming to ulcers to make themselves at home...
Meal Frequency Related to both of the above risk factors, meal frequency also plays a role in ulcer formation.
Horses are one of the few animals that constantly produce gastric acid whether or not there is feed in their stomach.
This should not be surprising, since they evolved as animals that continually grazed.
Since there is always acid being produced, if there is not a buffer (like saliva!) from eating many times a day, the
acidity in the tract will increase. The longer a horse goes without any food in front of him, the more acidic his
digestive tract becomes. Like we've mentioned before, this is practically screaming at ulcers to make themselves at
home...
The all too common practice of feeding horses twice daily has been shown to be a contributing factor to ulcers. The
best way to prevent this problem is to provide enough forage in those two feedings that the horse goes very little
time without forage between meals.
Prevention and Treatment of Equine Ulcers
Eliminating as many risk factors as possible from your horse's life is the best way to prevent ulcers. Obviously,
some factors, such as frequent showing or racing cannot be changed. However, other factors such as meal
composition and frequency can be changed with small changes to management practices.
If you suspect that your horse has ulcers, there are a few things that can be done.
Some owners choose to have their vet scope the animal to check for ulcers before treatment. However, others choose
to just assume the horse has ulcers because of the cost of scoping, as well as the fact that the procedure often misses
ulcers lower in the tract, where most ulcers are actually located.
Horses will usually show a great improvement within a few weeks of treatment being started, except in the most
severe cases.
Change of Management Practices Changing management practices is often the easiest and most cost-effective way to not only prevent ulcers, but to
treat them as well.
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 38
Reducing the acid level in the digestive tract by providing continual forage often goes a long way towards treatment
of mild cases of ulcers. Removal of high starch meals (or decreased size and increased frequency) also helps to
reduce the acidity.
Commercial Products Changing management practices may not be enough to take care of more severe cases of ulcers. In these cases,
commercial ulcer products are often very helpful in protecting the digestive tract long enough for it to heal.
However, its important to note that management changes will need to be made to minimize the risk of the ulcers
returning.
Commercial Prevention Products For horses with chronic ulcers who are not helped even after treatment with commercial products and all feasible
management changes have been made, there are commercial prevention products available.
These products are usually added to the feed on a daily basis to help maintain the pH of the digestive tract.
However, these preventatives can be very costly, so are often a last resort for most horse owners.
Equine ulcers can be a very painful problem for many horses. However, with proper management and treatment they
can be eliminated from most horses.
Equine thrush is a disease that affects the horse's hoof. It is a bacterial infection which usually settles in the
frog of the foot, but can spread throughout the hoof if not treated properly.
The good news is that the bacteria that causes thrush is anaerobic. This means that it cannot survive in the presence
of oxygen...
...so all you need to do to keep your horse's hooves free from thrush is to keep them exposed to air...
...which is WAY easier said than done, I know!
Signs of Equine Thrush
Horse thrush can be recognized by two distinctive signs:
1. A black gooey like substance that leaves a dark stain
2. An odor so offensive that it'll almost knock you off your feet
Now, we all know our horse's feet go through some pretty nasty things on a daily basis...so their feet can smell
pretty bad anyways, even when there is not thrush. But if the stench is accompanied by the goo, or gets excessively
worse fairly sudden, there is a pretty good chance that it is probably thrush.
The picture below shows what equine thrush looks like:
Equine Thrush
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 39
Equine Thrush Remedies
There are a number of remedies on the market for equine thrush, all which work pretty well. Make sure
when you apply these remedies that you coat all areas of the hoof well, working it into the cracks and
crevices.
Products such as Hoof Magic Thrush Antiseptic Treatment (left) are available in most tack stores, as well
as horse product catalogs.
You can click on the bottle to the left to purchase Hoof Magic from Shop.com, or both Stateline Tack and
Jeffers Equine have a good selection of thrush remedies if you prefer a different brand.
Click on the name of either of these companies to be taken to their website where you can view and
purchase their thrush products.
Do be aware, if you are not already, that many of these treatments are dyed, allowing you to see clearly
where they have been applied.
However, they also dye everything else they touch, including you, the barn floor, the too-curious-for-his-
own-good barn dog's nose...
...and the list goes on.
After having treated numerous cases of thrush and having green hoof-prints marching up and down my
concrete driveway, I stumbled (literally!) upon a great solution to the staining problem...
...I put the medicine to be applied in a cheap spray bottle and spray it on the hoof.
One or two squirts effectively covers the entire bottom of the hoof, and gets into the cracks and crevices pretty good.
Because the spray bottle only applies a thin layer (instead of the thick layer you usually get if you try to apply from
the bottle) it also shortens the drying time from unbearable minutes (which seem like hours when your horse is tired
of this and tries to turn it into a tug-o-war game!) to under a minute.
I do still wear gloves when using the squirt bottle though...
I learned that lesson the hard way when the sprayer malfunctioned and I ended up with green hands for a week! (Try
explaining that one to your school teachers!)
So, what does thrush have to do with nutrition?
I'm glad you asked!
Thrush is one of those opportunistic infections. The bacteria that cause thrush are always living in your horse's
environment. Most of the time they don't cause a problem. However, if something compromises the hoof, they are
more than happy to move in!
In the case of equine thrush, many times the hoof is simply compromised by not having access to dry areas to stand.
However, if your horse often gets thrush, even when he has dry places to stand, his nutrition could be playing a role.
If he is not getting adequate nutrition, not only is his immune system compromised, but his hoof will not be as
strong as it could be...which leads to him suffering from medical problems that otherwise would probably not occur.
Improved nutrition will increase the strength and durability of his hoof, and allow him to fight off the thrush-causing
bacteria on his own more easily before it ever becomes a problem.
Are you hopelessly confused by horse nutrition? Or are you confused about one or two smaller aspects of it? You
are not alone! Just like the little guy below, you want help and reassurance that you are doing things right (or you wouldn't be
searching the internet), but you also want to understand this stuff for yourself.
I understand, because I've been there.
You want the best for your horse, but understanding horse nutrition can be confusing...this website will help give
you the knowledge you need and start you on your path.
You’ve probably been asking yourself some of these questions:
Where do I start?
What does my horse need?
Confused by Horse Nutrition?
(and don't know where to start?!?)
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 40
How do I know if my feed is the best for my horse?
What does all that information on the feed bag mean?
What are all those ingredients? How do they affect my horse?
At one point I was asking myself the same questions. When I started researching to find answers, I was hopelessly
lost.
The more I researched, the more I realized how little I knew, and the more questions I had.
The biggest problem was that no one knew MY horse and his situation...I didn’t want someone -- like that annoying
feed salesman we've all met -- to tell me what THEY thought MY horse needed, I wanted someone to tell me how
to figure out what my horse needed, and in words I could understand! Understanding the items on the list below helps you understand horse nutrition, so you can relax and know that you
are feeding your horse to his highest potential!
Things that every horse owner should understand include:
How the horse digestive system works
Roughages and why they are essential
Other feedstuffs and if your horse needs them
The roles of major nutrients, vitamins, and minerals
How to read and understand the information on a feed tag
It sounds pretty simple, but as you probably know already, it can be daunting when you start trying to figure it out.
The good news is that it IS easy to understand, once you get over the initial hump!
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 41
Feeding Costs The cost of feeding a horse varies with the season and the availability of feed. Some approximate on-farm
costs of feedstuffs and supplements are given below. These costs will be higher in urban areas because of
additional expenses for transportation and handling.
Hay costs $50 to $140 per ton, or 2-1/2 cents to 7 cents per pound.
Oats cost $1.50 to $2 per bushel, or 4-1/2 to 6 cents per pound.
Shelled corn costs about $2 to $3 per bushel, or 3-1/2 to 5-1/2 cents per pound.
Soybean meal (42 to 50 percent crude protein) costs about $150 per ton, or 7-1/2 cents per pound.
Linseed meal (36 percent crude protein) costs about $150 per ton, or 7-1/2 cents per pound.
Complete pelleted feed costs $220 to $250 per ton, or 11 to 12-1/2 cents per pound.
Dicalclion phosphate costs about $15 per 100 pounds, or 15 cents pound.
Trace-mineralized salt costs about $8 per 100 pounds, or 8 cents per pound.
Three examples of the cost of feeding a horse are given below. These figures assume that a horse
consumes about 2 pounds of feed 100 pounds of body weight per day.
Example A: Horse weighing 1,000 pounds fed only mixed grasslegume hay. 1,100 pounds X 2 pounds per hundredweight = 22 pounds hay daily
22 pounds X 365 days 8,030 pounds hay annually
8,030 pounds X 5 cents = $401.50 annual cost
Example B: Horse weighing 1,100 pounds and working about 3 to 6 hours per day fed grain, hay,
and meal. 11 pounds grain X 5-1/2 cents per pound = 60-1/2 cents
13 pounds grass hay X 4 cents per pound = 52 cents
1 pound soybean or linseed meal X 7-1/2 cents = 7-1/2 cents
Total daily cost = $1.20
Total annual cost: $1.20 X 365 days =: $438
Example C: Horse weighing 1,000 pounds fed a complete pelleted ration. 1,100 pounds X 2 pounds per hundredweight = 22 pounds daily
22 pounds pellets X 12-1/2 cents per pound = $2.75
Total annual cost: $2.75 X 365 days = $1,003.75
____________________________________________________________________________________
You can convert the Value according to the Currency of your interest.
Chapter # 05 Feeding Cost Estimation
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 42
Some Feeding Questions and Answers 1. Can ear corn be fed to horses? Ear corn is a satisfactory feed, assuming it is adequately dried and free from
mold. It is good for greedy horses that bolt grain.
2. Are pelleted rations satisfactory? Yes. Pelleted rations have proven popular because they are convenient to
handle, easily stored, and reduce dustiness. However, grinding and pelleting increase ration costs.
3. What causes wood chewing and how can it be minimized? Wood chewing may be a result of boredom or of
a deficiency in the diet. Boredom may be reduced by feeding three times daily, increasing exercise, or
offering some additional straw or coarse hay to the horse when feeding pellets.
4. Can silage be fed to horses? The use of silage requires especially good management. However, good-
quality silage free from mold and not frozen can be a good roughage during the winter. If silage is fed, it is
a good idea to also use 3 to 4 pounds of dry hay daily.
5. How many pounds of silage are equivalent to a pound of hay? Corn silage is ensiled at 60 to 65 percent
moisture. About 2.5 wet pounds of corn silage are equal to 1 pound of air-dry hay. Grasses and legumes are
usually ensiled at 40 to 50 percent moisture and are called haylage. About 1.6 pounds of wet haylage is
equal to I pound of air-dry hay.
6. Of what value is molasses? Wet or dry molasses are sometimes included in the ration to increase
palatability and consumption. To keep the ration from being too laxative, it should not include more than 4
to 5 percent molasses.
7. If legume bays analyze higher in crude protein, why do horsemen often prefer grass hay? Grass hays often
cure more easily and thus are considered to be cleaner and less apt to contain mold.
8. Is it advisable to limit feed hay? Hay is often limited for race horses to insure an ingestion of more energy
from grain. Roughage is sometimes limited for show horses to avoid hay bellies.
9. Is it possible to feed rations that are too rich? Yes. Overfeeding, or bringing to a heavy feed of grain too
quickly without sufficient exercise, can result in colic, stocked legs, and puffy or swollen hocks.
10. How can greedy horses be prevented from bolting or eating their grain too quickly? Put a few baseball-
sized smooth stones in the grain box. Ear corn will also help.
11. What is founder? Founder is a metabolic disorder resulting from overeating, drinking cold water when
overheated, or other types of stress. It can lead to separation of live and horny portions of the hoof, which
causes severe lameness. Immediately placing cold packs on the horse's legs or standing the front legs in
cold water are good first aid measures. Severe cases require the attention of a veterinarian.
12. What is colic? Colic is simply a bellyache and can result from any number of causes. Drenching with a pint
of mineral oil or several quarts of water containing one half cup of salt or epsom salt may offer relief. Colic
should always be considered an emergency; consult a veterinarian.
13. Can horses use urea or other nonprotein nitrogen sources for protein? Not efficiently because the cecum (a
pouch of the large intestine where nonprotein nitrogen would be converted to useful protein) is located too
far down the digestive tract. Too much urea could be toxic to the horse so avoid using it.
14. Do antibiotics improve growth? The feeding of 85 milligrams of aureomycin daily to foals up to 1 year old
improves growth rates slightly. When properly prescribed, antibiotics appear to be more desirable for
therapeutic uses for diseases.
15. What should one look for on a feed tag or label when buying commercial horse feed? Take special note of
the percentages of total digestible nutrients (TDN) if provided, crude protein (CP), crude fiber (CF), and the
feed ingredients. Also be sure to read the feeding directions.
16. What is meant by percent T.D.N.? The percent T.D.N. (total digestible nutrients) is that part of the ration
that will be digested and retained in the horse's body as energy.
17. Of what significance is crude fiber (C.F.) in the ration? Generally, the higher the percent crude fiber, the
lower the percent T.D.N. in the ration. Shelled corn analyzes about 3 percent crude fiber, oats 12 percent,
and hays 24 to 30 percent. Rations analyzing more than 8 to 12 percent crude fiber probably contain
considerable roughage.
18. Can an orphan foal be raised on cow's milk? Yes, but at the beginning it is desirable for the foal to receive
some colostrum. There are also milk replacers available on the market.
19. How should cow's milk be modified for a foal? Mare's milk, as compared with cow's milk, is lower in
protein and fat and higher in water and sugar. Therefore, add one tablespoon of sugar and four tablespoons
of water to a pint of cow's milk. Warm to about 100' F. and feed 1/2 pint every two hours for the first few
days. After four weeks the foal can be gradually switched to undiluted cow's milk or skimmed milk.
Appendix
The Basics of Equine Nutrition And Feeding Suggestions for Horses
______________________________________________________________________________
__________________________________________________________________________________________________________________ https://www.facebook.com/vetcareservices Page 43
20. Why furnish extra vitamin A in the ration if green feeds are a good source of carotene that can be converted
to vitamin A in the body? Research has shown that high uptake of nitrogen in plants can interfere with
carotene conversion to vitamin A. Vitamin A is especially important for breeding horses. Supplemental
vitamin A is inexpensive and good insurance for the horse's health.
21. Should salt be fed loose or in the block? Salt can be fed either way, but consumption may be higher in the
loose form.
22. Do mares need grain before foaling? Mares fed good bay and in thrifty condition (healthy and neither fat
nor thin) may not need extra grain. Thin or old mares may need some grain. In late gestation, a light grain
ration along with good roughage is acceptable, but the mare should not be overfed. Heavy feeding can
cause foaling trouble because the mare may become too fat.
23. How should mares be fed after foaling? Feed only light grain with hay for 7 to 10 days after foaling.
Lactation that is too heavy can cause scouring. Increase grain slowly for the mare until the foal is old
enough to take more milk.
24. Do horses need tooth care? Yes. Irregular wear may leave sharp jagged edges that can cause pain or poor
mastication of feed. File with a float or guarded rasp. Occasionally milk teeth that remain in too long need
to be pulled; otherwise they may cause crooked permanent teeth.
References and Supplemental Reading
Feeding Suggestions For Horses
http://www.aces.uiuc.edu/vista/html_pubs/horse/horse.html Horse Diseases Related to Nutrition
http://www.understanding-horse-nutrition.com/horse-diseases.html
Nutritional Diseases of Horses
http://www.merckmanuals.com/vet/management_and_nutrition/nutrition_horses/nutritional_di
seases_of_horses.html Lewis, L.D. 1995. Feeding and Care of the Horse (2nd edition). Williams & Wilkins, Philadelphia, PA. National Research Council. 1989. Nutrient Requirements of Horses. National Academy Press, Washington, DC. Ralston S.L. 1993. Analysis of Feeds and Forages of Horses. Rutgers Cooperative Extension. FS714.
http://esc.rutgers.edu/publications/factsheets_nutrition/FS038.htm
© http://www.dratiqullahkhan.yolasite.com