Considerations for extralabel drug use in calves

Calfhood diseases have major negative economic consequences on beef and dairy operations owing to costs associated with treatment, long-term effects on growth and performance, and death of affected calves. ^1-3The number of drugs approved for the treatment of diseased calves by the FDA is limited; however, veterinarians have the authority to administer drugs in an extralabel manner to that class of animals under provisions established by AMDUCA.4 Nevertheless, drug labels that state, “a withdrawal period has not been established for this product in preruminating calves” can cause confusion about whether those drugs can or cannot be administered to young calves. Pharmacokinetic and residue depletion studies for very few drugs have been performed in young calves, and extrapolation of drug WDTs established for adult cattle to calves might not be appropriate or adequate to avoid violative tissue residues, which makes ELDU in calves problematic and potentially difficult to justify. The purpose of this digest is to provide veterinarians with a summary of the considerations for ELDU in both beef and dairy calves as well as calves intended for veal production.