IN FEMALE BOVINE REGULATION AND CONTROL OF THE TIME OF ESTRUS AND OVULATION

摘要

This invention concerns a method for fertile breeding control in female bovine by sequentially administering a progestin followed by a luteolytic agent. The progestin blocks estrus and ovulation and is administered in a manner to retain sufficiently high blood levels for that purpose for about 4 to 12 days. A luteolytic substance is then administered. 17 alpha -Acetoxy-11 beta -methyl-19-norpregn-4-ene-3,20-dione is incorporated in a polymer consisting of a major amount of 2-hydroxyethyl methacrylate and a minor amount of ethylene glycol methacrylate to form an implant which is implanted to establish an estrus and ovulation blocking period. The progestin regimen is followed by a single dose of PGF2 alpha as a luteolytic agent. The onset of estrus occurs 1 to 5 days after the administration of the luteolytic agent and the animals are bred by artificial or natural insemination.