Session 12:
Avian and Snake
Nutrition
Feeding Pet Birds
Types of Birds
Psittacine Breeds Passerine Breeds
Natural seed eatersSeasonal migratory birds
ParakeetsBudgiesCockatooMacawParrotsLovebirds
CanariesWrensSwallowsWarblersBlackbirdsCrows
Digestive Physiology of Birds
Differences in beak shape and size reflect adaptations to dietary sources of food
Stomach divided into distinct sections to compensate for lack of teeth and smaller amounts of saliva
Crop – used for wetting food and temporary storage
Mouth
Crop
Gizzard
Intestine
Ceca
Cloaca
Cloacal aperture
Esophagus
Digestive Physiology of Birds
Proventriculus
Digestive Physiology of Birds
Proventriculus (aka “true stomach”) – where gastric acids and enzymes begin chemical digestion
Gizzard (aka “ventriculus”) – strong muscular organ used to grind feed into smaller particles
Mouth
Crop
Proventriculus
Gizzard
Intestine
Ceca
Cloaca
Cloacal aperture
Esophagus
Intestine & Ceca – sites of nutrient absorption. Cecum is very small (or non-existent in some) so high fiber diets are out!
Cloaca – where urinary and digestive tract reunite. Urinary and fecal matter are mixed & excreted together
Mouth
Crop
Proventriculus
Gizzard
Intestine
Ceca
Cloaca
Cloacal aperture
Esophagus
Digestive Physiology of Birds
Digestive Transit Time
Definition: Time from the ingestion of food to the time when the undigested food is excreted.
Birds must have a constant supply of food. Some birds can be in a state of starvation within three days!Digestive Transit Times by
Species
Dairy Cattle: 24-72 hoursHumans: 18-24 hoursDogs and Cats: 12-18 hoursCaged Birds: <12 hoursBudgies & Finches: 3-6 hours
Of Special Note in Avian DigestionFaster metabolism
Must have “animal” vitamin D3, cholcalciferol
Require Proline and Glysine
Need increased amounts of sulfur amino acids
Extremely low urine volume; concentrated urine
Most do not utilize fiber
Avian Nutrition
Feed them based on their digestive tract ExampleOwls- Can’t drink based on the shape of their
beak- Can’t handle glucoseLorikeets- can’t handle protein
Faunivores
Carnivores and Piscivores- Adaptated to eating high protein diet
with a certain amount of fat - Cold water fish contain about 30% fat- Carnivores don’t utilize all of the prey,
they eat the mouse, digest as much as possible and then regurgitate the bones and hair ( owl pellets)
Insectivores
Can’t digest the entire insect- Some utilize the exoskeleton and some
penetrate the exoskeleton and digest the inside of the insect only
- When they eat the entire insect, they get all nutrients except Ca, which must be supplemented
- High protein requirement 50-75%- Insects high in protein and fat, low in Ca
Composition of Insects
Depends on species and stage of life cycle
Adult insects high in protein ( 50-75%) and lipid ( 5-35%) with low level of carbohydrates
Good source of vitamins, trace minerals and phosphorus, low in Calcium
Chitinous exoskeleton has a negative effect on digestibility
Florivores, Omnivores, HerbivoresFlorivores- nectovores, frugivores, garnivoresOmnivores- Most of our pet birdsHerbivores- Ratites- Combination of enzymes and microbes- Can be fore gut or hind gut fermenters
Precocial vs altricial birds
Precocial- Eat on own when hatched- Chickens, geese, ducks- Large yolk in egg with lots of nutients• Altricial- pigeon- crop milk- Hatchling dependent on parent for food- Eagles, owls, most of our pet birds
Seeding of the GI tract with microbes in young chicks Precocial chicks ingest the feces of
adult birds and feeds Altricial receive the bacteria when fed
by the adult ( regurgitated feed) “Cloacal drinking” vent “sucks” bacteria
in from the environment Retrograde urine, especially in ratites
Precocial chicks
Neonates have down, actively forage for their own food
Their digestive tract is immature when they hatch and takes up to 3 weeks to mature
Altricial chicks
Usually naked and helpless Parents must bring food to the chick and
actively feed it Digestive tract is well developed at hatch Milk production ( pigeons fed crop milk
for 2 weeks)- Crop milk nutritionally balanced, protein
and fat- Prolactin stimulates crop milk production
Nutritional Problems
Obesity- many pet birds and birds confined in zoos and sanctuaries
Leg abnormalities- confinement, improper diet, high
growth rates, vitamin D, Ca, P, Mn, Zn, niacin or biotin deficiencies
• Pendulous crop - Due to yeast overgrowth
Avian Feeding Management Birds tend to pick out certain seeds in mixes;
therefore don’t eat balanced diet
Should leave entire amount of food there until bird has eaten it all
Grass seeds (corn, oats, barley, etc) are too low in calcium; Sunflower, safflower seeds are too high in fat.
Best to feed a complete commercial feeding mix or pellets
Essential Nutrients & Ingredients in Avian DietsGrit:
made from ground minerals and sand; key in helping bird grind up foodstuffs; stays in the gizzard
Who needs grit?Birds that ingest whole seeds – helps with shellsBirds that remove seeds don’t really need grit
How to feed grit: 1/8 to ½ teaspoon every 2 years. Over
ingestion of grit causes intestinal impaction
Vitamin A: Promotes skin and mucous membrane health Feed high Vit A foods: carrot tops, broccoli,
sweet potatoes
Vitamin D (Cholcalciferol) Important in bone development Feed high calcium foods – almonds, cereals,
cheese, yogurt, oyster shells
Essential Nutrients & Ingredients in Avian Diets
What Budgies Eat
Prone to renal disease if fed 100% pelleted diet long term
Feed percentage of pellets, millet, sprouted seeds
Safe “human” foods: cooked pasta, brown rice, legumes, veggies, fruit, bread
Source: Oklahoma State University
What Cockatiels Eat Pellets Cereal & grain sources:
Cheerios, Chex, Total Dry or cooked pasta, corn, oatmeal Popcorn, crackers
Meaty, dark green, orange & yellow veggies
High Vit A content: beets, broccoli, carrots. NO lettuce, green peppers, zucchini, spinach!
Protein sources: legumes, tofu, small pieces of cooked lean meat
What Macaws Eat(Blue & Gold)
½ cup pellets with ½ cup fresh fruits and veggies (wash well!)
Seeds can be offered as treats (sunflower)
Protein sources: cooked sweet potato, yogurt
Fresh water at all times
What Parrots Eat
Commercial pellets for 60-80% of diet; Seeds less than 12% of diet
Table food: Mostly leafy green veggies, tomato, beets, peas,
carrots Unsweetened cereal; bread Small amounts of protein: cooked eggs, boiled
chicken, well done chicken bones
Limit seeds; leave shells on for parrot’s activity
What Canaries Eat
“Black and White” seed mix: 70% canary seed & 30% seeds from the rape seed plant; can use canary pellets
Very delicate, will dehydrate in short time; fresh water always!
Mineral grit and cuttlebone should be added
Sunflower seeds as a treat. Soak them overnight to help bird break them down
Source: University of Maryland
Chickens- layers that produce eggs, primarily Leghorn Starter feed- nutritional deficiencies and
imbalances may impair growth and future egg laying, contain antibiotics and coccidiostats
Grower- 6 weeks to sexual maturity approximately 21 weeks
Developer- can be inserted between grower and layer diet to increase production
Layer diet is fed free choice with large amounts of calcium for egg shell
Phase Feeding for Laying ChickensLayer phase 1-Birds are still growing and increasing in production, feed formulation is at maximum density-Onset of egg production until past the time of maximum egg mass output
Phase 2
Layer phase 2-High but declining egg production and increasing egg weight-Egg production declines to about 65 percent of maximum
Phase 3
Layer phase 3-Egg production continues to decline below 65 percent of maximum while egg weight decreases only slightly
There is no evidence that nutrient requirements of layers change during the period of lay
Molting
Layers are sometimes molted to extend the production period
Feed and light are restricted during the molt
Can also encourage a molt by nutrient excess or deficiency
Molt can last 3-6 weeks After molt laying resumes
Broilers
Eggs hatch in 21 days Starter diet is similar to layer diet but
more energy dense as broilers grow faster At 3 weeks, broilers are switched to a
lower nutrient density for the next 3-6 weeks
At 7 weeks the finisher diet begins. This diet is lower in nutrients and fed until market weight is reached
Reptiles
Nutrition of Boas and Pythons General Nutrition
Snakes consume whole prey, which makes a balanced diet easy
Balanced Diet Pet snakes usually fed “pinkies” In the wild, snakes eat mammals
birds, other reptiles, fish, wormsamphibians and bugs
Nutrition of Boas and Pythons Graduate from pinkies to mice to
rats to some rabbits
Try not to feed the snake food that is bigger than its midsection
Don’t handle snake after it’s eaten – it may regurgitate
Careful when snake is shedding – it can be aggressive
Nutrition of Boas and Pythons Never feed live prey – can result in
bite wounds
Teaching a snake to eat dead rodents: 1. Jiggle it by the tail and a hungry
snake will eat
2. Don’t use your fingers to dangle the prey – snakebites hurt
Nutrition of Boas and Pythons Feeding Frequency:
Juveniles: feed appropriately sized prey every 6-7 days
Adults: Feed every 7-14 days
Keep log of eating and defecation to monitor snake’s needs and potential illnesses
Nutrition of Boas and Pythons Ball Pythons
Shy feeders who do best with a hide box for shelter
If reluctant to eat, try feeding at night since they’re nocturnal
Imported Ball Pythons may not recognize classic white mouse as prey, so use brown mouse, gerbil or hamster
Nutrition of Boas and Pythons Water
Fresh water available at all times Provide a bowl or tub for them to submerge
themselves in for soaking
Temperature is important 80-95°F degrees for ball pythons
Iguanas
Cold blooded- Increase body temperature for optimum
digestion- Sunbathe for 4 hours- Forage for food after 4 hours of
warming/digestion- High protein requirement- Feeding dog food or cat food can lead
to gout due to uric acid accumulation
Iguana ( cont)
High fiber diets prevent many digestive problems
Vitamin deficiency can lead to pathologic fractures when iguanas are fed diets deficient in Ca and P
Utilize vitamin D3 like birds
Anole Nutrition
Insectivores so diet should consist mostly of insects
Feeder insects should be fed a high quality diet prior to being fed to the anole, this is called “gut loading” of insects ( there are many of these foods on the market)
Crickets, meal worms, houseflies, fruit flies, and silkworm
Anole ( con’t)
Also benefit from fruit nectar Dietary supplements including vitamins D-3
and mineral calcium will also be a benefit Watering can be difficult as anoles in the
wild drink dew and rainwater droplets so they will not utilize a bowl of water
It is recommend to mist the terrarium daily to provide the anole with drinking water
Turtles and Tortoises
All in the group of chelonians All posses a shell Tortoise are generally terrestrial
( however we refer to box turtles and wood turtles)
Turtle generally refers to water turtles Correctly feeding them begins with
identifying what type of chelonian you have
Land Tortoises
African Spur-thighed, Leopard, Star, Red-footed and Yellow-footed are examples
Should be placed outside in warm weather to graze, exercise and bask
( they like to dig, so bury an 8 inch barrier to prevent escape)
Provide sun and shade in enclosure Remove any toxic plants and foreign
material
Sunshine
Vital for turtles and tortoises for synthesis of vitamin D
If unable to provide an outdoor enclosure, provide a full spectrum flourescent light 12 inches or less above the turtle or tortoise
They are unable to absorb Vit D through a window
Tortoise Diet
95% vegetables Majority of vegetables should be dark,
green, leafy like collard, mustard, radish, turnip, kale, cabbage, dandelions, bok choy, broccoli leaves, clover, legumes, cut grass and weeds from yard ( no pesticides)
Small amounts of spinach, swiss chard, beet greens, frozen veggies
Tortoise diet ( cont)
Hibiscus flowers and leaves, grape leaves, carnations, roses, and squash flowers are favorites
Alfalfa pellets can be soaked and offered Fruits are well accepted but mineral poor
and incorrect Ca/P ratio Fruits can form 5% of diet melons, grapes,
apples, oranges, peaches, strawberries, raspberries, bananas with peel etc
Tortoise diet ( cont)
Red and yellow footed can eat more fruit, up to 20 %
Commercial tortoise diets can be soaked an used as a small portion of the diet
Chop entire daily diet of veggies, fruits and commercial diet together to avoid picking and choosing
If you don’t use turtle chow, add Ca supplement daily, vit. Supplement weekly
Offering food/water
Hatchling turtles and tortoises should be fed daily
Adults can be fed every other day or three times a week
Fresh clean water to drink in and soak in First year of life is very important since
they are growing rapidly, it is vital they receive a balanced diet to prevent bone and shell problems
Box Turtles
Fed a diet very different from tortoises Young box turtles will eat primarily
animal material such as earthworms, slugs, snails, beetles, millipedes, spiders, crayfish and grasshoppers
Chopped up pinky mice can also be used for juveniles
Commercial turtle chow can be offered in limited amounts
Box Turtle adults
Will eat plant material including mushrooms, tomatoes, strawberries, raspberries, and other fruits
Should eat about 50% animal protein and 50% plants ( 75% veggies and 25% fruit)
Utilized the fruits and veggies list for tortoises
Finicky Box Turtles
Build the diet around a commercially prepared box turtle chow and add animal and plant material
They need lots of beta carotene ( a precursor of Vit A) in the diet to prevent medical problems
Aquatic Turtles
Red eared sliders, painted turtles, mud and musk turtles, soft shell turtles, snapping turtles
All require clean warm water for swimming
Eat most of their meals in the water ( try to have a separate water dish for eating to prevent fouling of swimming water)
Allow an area where turtle can exit the water to bask
Aquatic Turtle diets
Feed a variety of foods Commercial floating food sticks as a
portion of the diet Small turtles should be offered chopped
earthworms, snails, slugs, shrimp in the shells, chopped up whole fish ( from frozen to kill parasites), chopped mice and gut-loaded insects
Raw chicken, lean beef, liver and gizzards limited
Aquatic turtles ( cont)
As water turtles get older, they will usually consume dark green leafy vegetables, ( see tortoise list)
Older turtles may also consume duckweed, anarchis, algae and some fruits, also offer floating food sticks
Diets too high in protein and other nutrients Shell abnormalities will result Fed exclusively primate chow, dog food
or cat food will usually develop grossly deformed shells, especially the top shell ( the carapace)
Shell may also become domed and misshapen
Obese animals have fat bulging from armpits and groin impeding locomotion
Temperature requirements for turtles and tortoises Correct temperature range for efficient
digestion In addition to poor digestion, they are
prone to many diseases Hibernation is recommended for turtles
and tortoises that hibernate in the wild who are in good physical condition ( consult a vet familiar with hibernating these species)
Iguana Nutrition
Vegetarians specifically foliovores Foliovores consume primarily leaves in
their natural environment Hindgut fermenters which require
microbes to assist in their digestion ( like cows)
Requires a high body temperature which is why iguanas will bask for about 4 hours in the morning before foraging for food
Iguanas in the wild
Eat leaves, fruit, flowers of selected herbs, shrubs, trees and vines
Dietary diversity does not occur on a daily basis
They tend to consume less common plants and seasonally available foods
Iguanas ( cont)
Young iguanas are foliovores just like the adults
All iguanas can develop a taste for inappropriate food items: popcorn, cheese, dog food
Monkey biscuits contain too much D3 which can cause mineralization of internal organs which will cause death
Dog food can lead to gout in iguanas
Appropriate diet size iguanas Hatchlings up to 14 inches finely
chopped food twice a day Older iguanas up to 3 feet in length can
be fed medium chopped food once daily Adults over 2 ½ years of age or over 3
ft in length fed coarsely chopped food every other day
All foods thoroughly washed, chopped and mixed
Composition of the Iguana
Baby iguanas are growing rapidly, incorrect diets can lead to deformed, ill animals
A high percentage of the diet dark-green leafy vegetables
80-90% of the diet should consist of two from this list: collard greens, turnip greens, mustard greens, bok choy, swiss chard, clover, red or green cabbage, water cress, savoy, dandelions, parsley, alfalfa pellets
Composition ( cont)
Beet greens an spinach contain oxalates that may bind dietary calcium should only be offered occassionally
Kale, brussels sprout, broccoli, cabbage, and cauliflower can bind iodine leading to goiter so they should also be limited
The darker outside leaves are more nutritious
Composition ( cont)
10-15 % of diet from frozen mixed veggies, squash, sprouts, carrots, cooked sweet potato, cucumber, okra, parsnips, asparagus, mushrooms, green and red peppers, peas, beans, corn and green beans
Backyard weeds and grasses as forage Fruits can make up the rest of the diet,
they are mineral poor so they are used for flavor
Acceptable fruits for Iguanas Papaya, mango, apple, peach, pear, plum,
strawberry, banana with the skin, raspberry, melon, tomato, grape, raisins, star fruit, kiwi, blueberry and guava
Figs are high in calcium Show grain breads or bran cereals can be
offered sparingly or prepared iguana food can be fed
Light green lettuce can be offered as a treat
Treats
Hibiscus leaves and flowers, rose petals, geranium flowers, carnations and dandelions
Live food is not necessary but some enjoy crickets, meal worms and pinky mice. These should be fed sparingly because they are poor dietary items for this species
Feeding continued
Avoid food preferences by providing 10 different food items in the daily diet and mix them thoroughly to prevent selection of preferred ingredients
Food items should have a positive calcium to phosphorus ratio
Most water is obtained from the diet so feed juicy, moist food
Feeding cont
Offer a large pan of water for soaking Most iguanas relieve themselves in the
water so this will also help keep the enclosure clean
Provide a well balanced diet and only supplement if recommended by your veterinarian. Oversupplementation can be detrimental to the iguana.
Bearded dragons
Omnivores, eating a mixture of invertebrates, vertebrates ( insects and small animals) and plant material
In captivity: feed a combination of insects ( mostly crickets) greens and vegetables
Insects for Bearded dragons Bearded dragons are prone to
impactions of their digestive tract and the chitinous exoskeletons of insect can cause problems
Mealworms can cause impactions so feed them in very limited quantities and avoid them in juveniles
Feed insects that have recently molted so the exoskeleton is soft
Insects ( cont)
Crickets should be no larger than the space between the dragons eyes
Adult dragons can be fed waxworms, silkworms, butterworms, red worms, earthworms, and newly molted mealworms and superworms as treats. Crickets should provide the bulk of the diet. You can occassionally offer a pinky mouse.
Juvenile Bearded Dragons
Should be fed insects more often than adults
Feed at least twice a day, the amount they will eat in 10 minutes
Heat is necessary for digestion so make sure it is appropriate
Greens and vegetables can be available at all times
Insects for Bearded dragons All insects should be gut loaded ( fed
nutritious food that is then passed to the lizard) and lightly dusted with a calcium and Vit D supplement
Dust with a complete multivitamin no more than once a week
Do not feed fireflies or boxelder bugs as they are believed to be toxic to bearded dragons
Greens and Vegetables should make up 20-30% of diet Mixture of green leafy vegetables ex
dandelion greens, collard greens, chickory greens, mustard greens, turnip greens, and parsley
Other vegetables; squash, carrots, green beans, peas, bell peppers
Some fruits: berries, apples, grapes, cantaloupes, papaya, mango, blueberries and bananas
Commercial Diets
Should only be used as a supplement or mixed in with the diet
Long term effects of commercial diets have not been determined