CONTROLLED-RELEASE PRODUCTS FOR THE CONTROL OF THE ESTRUS CYCLE IN CATTLE, SHEEP, GOATS, DEER, PIGS, AND HORSES

This paper describes the estrus cycles of a number of livestock breeds and reviews the controlled-release drug delivery systems that are cur rently available for the purpose of controlled breeding. The bovine es trus cycle is reviewed in detail, and the estrus cycles of other speci es are described in a manner that highlights similarities and differen ces between species. Pertinent formulation and pharmacokinetic informa tion about current drug delivery systems is presented and discussed, a nd recent advances in this area are also described.