The Effects of the Post-Insemination Administration of Combined Gonadotropin-Releasing Hormone and Flunixin Meglumine on Conception Rate and Serum Progesterone Concentration in Repeat-Breeder Dairy Cows

A repeat-breeder cow (RBC) is defined as any cow that is unable to conceive after three or more artificial inseminations (AI). This study was designed to investigate the effect of the administration of combined gonadotropin-releasing hormone (GnRH) and Flunixin meglumine (FM) in repeat-breeder cows. Eighty-six repeat-breeder cows were used and divided into four groups as follows: ۱) GnRH group (n = ۲۱): GnRH was administered on Day ۵ after AI. ۲) FM group (n = ۲۲): FM was administered on Day ۱۵ after AI. ۳) GnRH+FM group (n = ۲۰): GnRH and FM were administered on Days ۵ and ۱۵ after AI, respectively. ۴) Control group (n = ۲۳): the cows did not receive any drugs after AI. Blood samples from all groups were collected at ۰, ۵, ۱۵, ۲۲, and ۳۳ days after AI. The conception rate and pregnancy loss were not statistically different (P > ۰.۰۵) among the four groups, nor between primiparous and multiparous cows. In the four experimental groups, serum progesterone (P۴) concentrations at ۲۲ and ۳۳ days after AI were higher in pregnant cows than in non-pregnant cows (P < ۰.۰۵). At ۲۲ days after AI, serum P۴ concentration was higher in pregnant cows in group ۳ compared to group ۴ and group ۱ (P < ۰.۰۵). At ۳۳ days after AI, serum P۴ concentration was significantly higher in pregnant cows in group ۳ compared to group ۲ (P < ۰.۰۵). Pregnancy loss was numerically lower in the GnRH+FM group than in the control, GnRH, and FM groups; however, these differences were not statistically significant (P > ۰.۰۵). Therefore, administering GnRH+FM may be more effective in supporting pregnancy maintenance than administering either of these two drugs separately.

کلیدواژه ها:

Embryonic Loss ، conception rate ، Luteal Support ، reproductive performance ، Post-Insemination Treatment