Animal Science II Unit 7 Feed Additives & Hormone
Implants
Slide 2
Objectives Discuss the general use and purpose of feed
additives and hormone implants Describe the proper method of
hormone implantation Discuss the proper use of feed additives for
various species of animals Discuss labeling and regulation of feed
additives Discuss the proper mixing of feed additives in complete
rations Discuss health issues and concerns relating to the use of
feed additives.
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Feed Additives Used to Improve feed efficiency Promote faster
gains Improve health Increase production of animal products Not
considered nutrients Used in small amounts Require careful handling
and mixing Came into use in the early 1950s
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Hormone Implants Pelleted, Synthetic compounds Placed under the
skin or in the muscle Used to lower production costs by improving
both rate and efficiency of gain Mainly used in beef cattle
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Hormone Implants and Feed Additives Sometimes called
performance stimulants Wide variety have been developed, tested and
approved for use Some have been discontinued due to toxicity, cost,
lack of proven benefit or excessive residues in meat
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Types Antimicrobial compounds Antibiotics and
chemoanticacterials Hormones Hormone like substances Anthelmintics
Dewormers Buffering agents Feed flavors Bloat preventatives
Slide 7
Antimicrobial Drugs Kill or slow down the growth of some kinds
of microorganisms Often used as feed additives for livestock and
poultry Used at a subtherapeutic level of use to keep harmful
microbes under control
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Difference Between the Antibiotics and Chemoantibacterial
Compounds Major difference is in the way they are produced
Antibiotics are produced from living microorganisms
Chemoantibacterial compounds are made from chemicals An antibiotic
and antibacterial are combined into one compound called a
chemobiotic They are combined to combat a problem that is not
susceptible to either one individually
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Common Antibiotics Used in Livestock Production
Chlortetracycline (Aueromycin) Neomycin Oxytetracycline
(Terramycin) Penicillin Streptomycin Tylosin Polyether antibiotics
are called ionophores and are usually used in the production of
ruminant animals Monensin (Rumensin) Lasalocid sodium
(Bovatec)
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Common chemoantibacterial Compounds Carbadox Furazolidone
Nitrofurazone Sulfamethazine
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Use of Antibiotics Response varies among species and feeding
conditions Little or no benefit gained from the feeding of
antibiotics in conditions that are free of harmful microorganisms
Research in livestock nutrition shows several factors that explain
why antibiotics increase rate of gain, improve feed efficiency or
improve the general health of the animal
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Nutrient Sparing Substances The substance allows animals to use
available nutrients more effectively Some antibiotics stimulate
microbes in the digestive tract to produce more nutrients than they
would without the antibiotic
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Metabolic Rate in Young Growing Animals When fed at low levels
in the ration Increase daily feed intake Conversion of feed to meat
is faster and more efficient This is compared to animals that are
not fed antibiotics in their ration
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Subclinical Diseases Disease that is present in the animals
body at levels too low to cause visible effects Antibiotics can
control these disease continuously Result is a more vigorous and
healthy animal Also results in a more uniform rate of gain
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Broad and Narrow Spectrum Antibiotics Broad Spectrum- control
many different microorganisms Preferred for use as feed additives
Generally give better results in terms of rate of gain, feed
efficiency, improved animal health Narrow spectrum- control only a
few microorganisms Used to control specific disease problems that
may be present in the group
Slide 16
Hormones Produced in the animals body Natural hormones are
secreted into body fluids such as the bloodstream by various glands
in the body Regulate body functions such as growth, metabolism,
reproductive cycle
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Hormone like Compounds Synthetic substances that act like
hormones Both hormones and hormone like compounds are produced
commercially for use as feed additives, primarily in beef
nutrition
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Androgen, Progestogens, Estrogens Produced by sex glands of the
body Increase rate of protein synthesis and muscle development Used
in rations to improve feed efficiency and rate of growth Beef
cattle have shown the greatest response to these as feed additives
and implants
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The Controversy Over Hormone Use DES Approved in 1954
Disapproved in 1972 Reapproved Banned in 1979 European Union (EU)
Banned importation of meat for human consumption that has been
treated with anabolic agents 1988 WTO ruled that the EU ban was in
violation of trade laws As of summer 1999 the issue was not
resolved
Slide 20
Anthelmintics Dewormers May be provided in either feed or water
Worms reduce feed efficiency and rate of gain Good management
practices can also help keep worm infestations to a minimum.
Slide 21
Other Feed Additives Coccidiostats Used in poultry rations to
prevent coccidiosis Iodinated casein (Thyropotein) Used to increase
the amount of hormone thyroxin Poloxalene (Bloat Guard) Bloat
preventative Breaks up the foam and slime layer and allows gases to
escape the rumen Others Tranquilizers Antioxidants Copper compounds
Probiotics Organic acids