Optimizing Ovulation to First GnRH Improved Outcomes to Each Hormonal Injection of Ovsynch in Lactating Dairy Cows

Hormonal responses of dairy cows with ovarian cysts to GnRH.

Twenty-four cows, diagnosed via rectal palpation as having ovarian cysts were randomly assigned to one of four groups to receive a single IM injection of either 0, 50, 100 or 250 /lg of synthetic gonadotropin-releasing hormone (GnRH). Sixteen lactating dairy cows exhibiting clinically normal estrous cycles were used as controls. Of the 18 cows receiving 50, 100 or 250/ag GnRH, 13 (72%) responde...

P-64: Strategies to Optimize Reproductive Efficiencyby Regulation of Ovarian Function inyak (Poephagus Grunniens L.)

Background: To design a pre-Ovsynch hormonal strategy in yaks in order to increase the ovulatory response to the first GnRH injection of Ovsynch so that overall synchronization rate to Ovsynch could be improved. Materials and Methods: Non-lactating cyclic yak cows (n=33) were assigned to receive either no treatment before Ovsynch (control) or 0.375mg of PGF2(PreP) followed 2 d later by 10 g of ...

Strategic use of gonadotrophin-releasing hormone (GnRH) to increase pregnancy rate and reduce pregnancy loss in lactating dairy cows subjected to synchronization of ovulation and timed insemination.

The objective of this study was to determine the effect of GnRH (100 microg i.m.) treatment 5 and 15 days after timed insemination (TAI) on pregnancy rate and pregnancy loss in lactating dairy cows subjected to synchronization of ovulation. The study included 831 lactating dairy cows subjected to a Presynch-Ovsynch protocol for first service. On the day of TAI (Day 0), cows were randomly assign...

Effect of yeast culture supplementation of alfalfa silage or alfalfa hay fed to lactating dairy cows

Production, Management and the Environment: Reproduction and Health Management

The objective was to evaluate whether addition of EAZI-BREED CIDR Cattle Inserts (CIDR) to the Ovsynch program increases first service pregnancy rate (PR) in lactating dairy cows. The study was conducted in 5 dairies in Central Mexico. Cows were inseminated from June through September, 2001. Within trial site and within parity, cows were assigned to either an Ovsynch (n=255) or an Ovsynch-CIDR ...