The FDA has amended its regulations to reclassify sheep as a minor species for all data collection purposes. The reclassification allows sponsors of new animal drug applications to extrapolate human food safety data from a major species to sheep, as well as tolerances for residues of new animal drugs in cattle to sheep.

The rule, published in the Aug 3 Federal Register, became effective Sept 5.

In 1999, the FDA proposed amending a provision from federal regulations that would allow sheep to be classified as a minor species for all data-collection purposes. The agency had begun to rethink the issue after new data became available. The FDA had formerly categorized sheep as a minor species with respect to effectiveness on animal safety data collection, and as a major species with respect to human food safety data collection.

The new data concern the similarity of drug metabolism between sheep and cattle. Although consumption levels can be a factor in determining species classification, the FDA believes that the evidence regarding drug metabolism is more reliable in determining the species status of sheep than are consumption data. The facts demonstrate the reliability of data extrapolated from cattle to sheep, according to the agency.

The FDA received seven comments, all supportive of the proposed rule, including one from the AVMA. Relatedly, Congress is considering a bill that would increase the amount of drugs available for use in minor species (see JAVMA, Aug 15, 2000, page 460). Because of a paucity of approved drugs, the US sheep industry suffers millions of dollars of losses annually to otherwise treatable illnesses.