1. Nutrition and Feeds Feed Additives

2. 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.

3. 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)

4. Common Feed Additives Antibiotics Hormones Arsenicals Dynafac Dry rumen bacteria Detergents or surfactants

5. 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

6. 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.

7. 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.

8. Dynafac Minimizes bloat and founder

9. Dry Rumen Bacteria Fed to cattle to stimulate rumen bacterial development

10. Detergents and Surfactants Used to reduce and stop foaming to prevent bloating

11. 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

12. Other Additives cont. Ronnel - controls grubs Thibenzole - controls internal parasites Melengestrol Acetate - used to depress heat in heifers which generally improves feedlot performance

13. Sources of Feed Additives Commercial prepared feeds Farm produced feeds contain additives when added to the diet from a commercially prepared premix.

14. 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.