Pregnancy outcomes in two commercial dairy herds following hormonal scheduling programs

There are a number of options for hormonal management of post partum dairy cows; however, only a few studies have made direct comparisons of these pro grams in commercial herd settings. We compared reproductive management prog rams of 2 commercial dairy herds to evaluate the efficacy of prostaglandin- based treatment regimens on reproductive outcomes. Cows in Herd A were left untreated and served as the negative controls. Cows in Herd B were given P GF(2 alpha) every 14 d until first insemination beginning 45 d post partum and served as the positive controls. Treatment 1 (Ovsynch), initiated rando mly during the estrous cycle, consisted of sequential injections of GnRH, P GF(2 alpha), GnRH again and insemination 16 to 20 h later. Treatment 2 cons isted of an Ovsynch protocol, as described above, which was begun 7 d post estrus (Ovsynch + 7). In Herd A, the number of days from parturition to con ception (days open) for controls, for Ovsynch and for Ovsynch + 7 were 126, 112 and 102, respectively. In Herd B, respective days open were 102, 100 a nd 93 for controls, Ovsynch and Ovsynch + 7. Hormonal intervention reduced the number of days open in both herds. (C) 1999 by Elsevier Science Inc.