American horses are given a steady diet of drugs throughout their lives barring their meat from entering the human food chain.
Certain drugs barred from use for slaughter horses have a zero withdrawal period; others a six month withdrawal period.
However, It is challenging to imagine a scenario where a horse intended for slaughter for human consumption is withheld from slaughter for the minimum time period. It is simply not the nature of the business.
The most common drug administered to the American horse is Phenylbutazone, or “Bute”.
Bute is banned for use in all food animals.
An estimated 85% of all American horses are treated with Bute. However, it is difficult to imagine any American horse who has not been treated with Bute at one time for another.
Bute comes in the form of tablets, liquid, gel, paste and powder. A horse treated with Bute is barred from slaughter.
• Phenylbutazone ("Bute")
• Clenbuterol (Ventipulmin)
• Diethylstilbestrol (DES)
• Ipronidazole and other nitroimidazoles (including metronidazole)
• Furazolidone, Nitrofurazone, other nitrofurans
• Dapsone (4-[(4-aminobenzene)sulfonyl]aniline)
• Glycopeptides (antibiotics such as vancomycin)
Gentian violet (Tris(4-(dimethylamino)phenyl)methylium chloride)
• Aristolochic acid (8-methoxy-6-nitrophenanthro[3,4-d][1,3]dioxole-5-carboxylic acid) and preparations thereof
• Hormonal steroids for growth promotion purposes (testosterone, progesterone, trenbolone and derivatives)
• Anabolic or gestagenic steroids for therapeutic and/or zootechnical purposes (boldenone and estrogens such as 17ßestradiol, estriol, and other sex hormones).
• All ß-agonists (e.g. compounds belonging to the Clenbuterol family)
• Stilbenes ((E)-1,2-Diphenylethene and isomers), salts and esters.
• Thyrostats (Thyroid hormones, derivatives like Levothyroxine and their agonist such as thiouracils and sulfur-containing imidazoles)
• Altrenogest (gestagenic agent, MRLs set to 1 μg/kg in fat and 0.9 μg/kg in liver)
• Carprofen (NSAID with uses similar to phenylbutazone but less potent; MRLs set to 500 μg/kg in muscle, 1,000 μg/kg in fat, liver and kidney)
• Cefquinome (antibiotic; MRLs set to 100 μg/kg in liver and 200 μg/kg in kidney)
• Ceftiofur (antibiotic; MRLs set to 1,000 μg/kg in muscle, 2,000 μg/kg in fat and liver and 6,000 μg/kg in kidney)
• Dexamethasone (corticosteroid; MRLs set to 0,75 μg/kg in muscle, 2 μg/kg in liver and 0.75 μg/kg in kidney)
• Febantel, Fenbendazole and oxfendazole sulphone (antiparasitic agent; MRLs set to 50 μg/kg in muscle, fat and kidney and 500 μg/kg in liver)
• Firocoxib (NSAID; MRLs set to 10 μg/kg in muscle and kidney, 15 μg/kg in fat and 60 μg/kg in liver).
• Flunixin (NSAID; MRLs set to 10 μg/kg in muscle, 20 μg/kg in fat, 100 μg/kg in liver and 200 μg/kg in kidney)
• Ivermectin (antiparasitic agent; MRLs set to 100 μg/kg in fat and liver and 30 μg/kg in kidney)
• Kanamycin (antibiotic; MRLs set to 100 μg/kg in muscle and fat, 600 μg/kg in liver and 2,500 μg/kg in kidney)
• Mebendazole (antiparasitic agent; MRLs set to 60 μg/kg in muscle, fat and kidney and 400 μg/kg in liver)
• Meloxicam (NSAID; MRLs set to 20 μg/kg in muscle and 65 μg/kg in liver and kidney)
• Metamizole (NSAID; MRLs set to 100 μg/kg in all relevant tissues)
• Moxidectin (antiparasitic agent; MRLs set to 50 μg/kg in muscle, and kidney , 500 μg/kg in fat and 100 μg/kg in liver)
• Neomycin (antibiotic; MRLs set to 500 μg/kg in muscle, fat and liver and 5,000 μg/kg in kidney)
• Trimethoprim (anti-infectious and chemotherapy agent; MRLs set to 100 μg/kg in all relevant tissues)
• Vedaprofen (NSAID; MRLs set to 50 μg/kg in muscle, 20 μg/kg in fat, 100 μg/kg in liver and 1,000 μg/kg in kidney)
Although Bute is the most commonly given drug, all the drugs listed above are routinely given to horses in a daily basis throughout the United States, especially those involved in racing.
However, not only are medicines administered to U.S. equines, but compounds not catalogued per se as “medicines” are also frequently given to U.S. horses, such as dimethyl sulfoxide (an lab grade polar aprotic solvent used as a liniment on horses to treat sore legs), protein supplements and, much like beef cattle, bone meal, which is a known vector for BSE or “mad cow” disease.
Bearing in mind the negative effects on human health it is understandable why authorities both in the U.S. and abroad prohibit animals treated with such drugs from entering the human food chain.
See Section 530.41 of Title 21 of US Code of Federal Regulations, provisions of the Federal Food, Drugs and Cosmetics Act (21 U.S.C. §301 et seq.);
See also provisions of European Commission (EU) Regulation No. 37/2010 and European Council Directive 96/22/EC several medicines commonly used in horse husbandry in the U.S. have been totally banned from use in animals (regardless of species) intended to be slaughtered for human food.
© THE HORSE FUND 2019