PSV-B-15 Comparison of the 7-day Cosynch and 8-day Estradiol-Based Protocols for Synchronization of Ovulation and Timed Artificial Insemination in Suckled Bos Taurus Cows

Abstract The objective was to compare pregnancy rates (PR) on day 30 and loss between days 60 (PL) after timed artificial insemination (TAI; 0) using 2 synchronization protocols, plasma progesterone 18 in suckled beef cows. Angus cows were randomly assigned either 7-d CoSynch (7-d P + GnRH) or 8-d estradiol (8-d ES) protocols for TAI. On -10, the GnRH treatment group (n=574) received a progesterone-releasing intravaginal device (PIVD) GnRH, -3 PIVD removed cloprostenol. 0 (64 h removal), subjected Day ES benzoate, -2 removed, cloprostenol cypionate. (48 TAI each determined 60. In subset of [n=81, n=41; ES, n=40)], serum concentration evaluated 18. PR GnRH=48.9%; ES=45.6%) PL GnRH=3.6%; ES=4.6%) did not differ (P≥0.28) groups. cows, (P=0.67) groups but tended be less (P=0.07) that had compared with no PL. conclusion, there difference estradiol-based ovulation