The effect of GnRH injection at the day of 12 following artificial insemination on Ovsynch applicated dairy cows

This research aims to analyze the effect of ovsynch and addition to this injection of GnRH after artificial insemination, at the day of 12, on pregnancy ratiosAs research material, 60 Holstein cows, located in İzmir between the day of 50.-75. at postpartum were used. Animals were divided into three groups, each group included 20 cows regardless of showing estrus signs or not. The 1.group (control) were inseminated artificially at the time of normal estrus time. The 2.group cows (ovsynch program) were injected GnRH on the day 0, PGF2? on day 7 and again GnRH on day 9; regardless of estrus cycle period. 16 hours later, in day 9; artificial insemination was administered. To the 3. group (ovsynch + 12.GnRH), the same ovsynch procedure was applied and after artificial insemination, on day 12, GnRH was administered. The pregnancies of animals were determined on day 60 and 90 by rectal palpation. The pregnancy rates were 75, 55, 65% in groups 1, 2, 3, respectively. There were no statistical differencies between groupsAs a result, ovsynch and GnRH administration at the day of 12 after artificial inseminiation, are useful to control and manage the reproductive health program of the cows and to be able to take measures of embryonic mortality caused by means of getting rid of luteal insufficiency.