Nutrition and Feeds
Feed Additives
Feed Additives vs. Food Nutrient
• Feed additive residues may be found in the
liver, fat tissue, and muscle.
• A food nutrient becomes part of the body
cells and is necessary for the proper
function of these cells.
Function of Feed Additives
• Promote growth and production
• Improve feed efficiency
• Provide prevention and treatment for
internal parasites and diseases
• Provide specific actions or results in
specific species (e.g. what works on pigs
may not work on cattle)
Common Feed Additives
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Antibiotics
Hormones
Arsenicals
Dynafac
Dry rumen bacteria
Detergents or surfactants
Antibiotics
• Do not cause a marked change in meat quality any effects would be INDIRECT, resulting from
improved general health (more rapid weight gains)
• Examples: Aureomycin, Terramycin, Penicillin,
Zinc Bacitracin, Hygromycin B, and Streptomycin
• Uses of antibiotics vary - in many cases use of
them promotes growth (INDIRECTLY) and
reduces the number of “unthrifty” animals
Antibiotics cont.
• Use of antibiotics in feeds may give rise to
population of bacteria which may be
resistant to penicillin, the tetracylclines, and
other antibiotics.
– Thus, resistance might interfere with
subsequent treatment of sick livestock.
– This resistance might be transferred to bacteria
in humans, leading to the possiblity fo
untreatable diseases in humans.
Arsenicals
• Are arsenic compounds
• Used to prevent blackhead in turkeys and
coccidiosis in chickens
• Considered helpful in stimulating growth in chicks
and pigs
• Examples: arsenilic acid, sodium arsenilate, and
hydroxyphenyl arsenic acid
• When birds and animals are removed from
arsenic-containing feeds a few days before
slaughter, no residues remain.
Dynafac
• Minimizes bloat and founder
Dry Rumen Bacteria
• Fed to cattle to stimulate rumen bacterial
development
Detergents and Surfactants
• Used to reduce and stop foaming to prevent
bloating
Other Additives
(recommended for cattle)
• Erythromycin (anitbiotic) - improves
growth
• Neomycin (antibiotic) - prevents scours
• Ethylene Diamine Dihydroiodide - prevents
foot rot and lumpy jaw
• Poloxalene (surfactant) - prevents bloat
• Ammonia Chloride (chemical) - prevents
urinary calculi
Other Additives cont.
• Ronnel - controls grubs
• Thibenzole - controls internal parasites
• Melengestrol Acetate - used to depress heat
in heifers which generally improves feedlot
performance
Sources of Feed Additives
• Commercial prepared feeds
• Farm produced feeds contain additives
when added to the diet from a commercially
prepared premix.
Slaughter
• Most animals must be stopped at a
predetermined time BEFORE slaughter.
This gives the animals time to “clear” any
residues which could be harmful to
consumers.