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- Title
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.
- Authors
Rodriguez, Alejandro M.; Maresca, Sebastian; López-Valiente, Sebastian O.; Bilbao, Maria G.; Moran, Karen D.; Bartolome, Julián A.; Pratt, Scott L.; Long, Nathan M.
- Abstract
The objective was to compare pregnancy rates (PR) on day 30 and pregnancy loss between days 30 and 60 (PL) after timed artificial insemination (TAI; day 0) using 2 synchronization protocols, and plasma progesterone on day 18 in suckled beef cows. Angus cows were randomly assigned to either 7-d progesterone CoSynch (7-d P + GnRH) or 8-d progesterone + estradiol (8-d P + ES) synchronization protocols for TAI. On day -10, cows in the 7-d P + GnRH treatment group (n=574) received a progesterone-releasing intravaginal device (PIVD) and GnRH, on day -3 the PIVD was removed and cows received cloprostenol. On day 0 (64 h after PIVD removal), cows received GnRH and were subjected to TAI. On Day -10, cows in the 8-d P + ES treatment group (n=574) received a PIVD and estradiol benzoate, on Day -2 the PIVD was removed, and cows received cloprostenol and estradiol cypionate. On day 0 (48 h after PIVD removal), cows were subjected to TAI. The TAI pregnancy rates for each treatment were determined on day 30 and day 60. In a subset of cows [n=81, (7-d P + GnRH, n=41; 8-d P + ES, n=40)], serum progesterone concentration was evaluated on day 18. The PR (7-d P + GnRH=48.9%; 8-d P + ES=45.6%) and PL (7-d P + GnRH=3.6%; 8-d P + ES=4.6%) did not differ (P=0.28) between treatment groups. In a subset of cows, serum progesterone concentration on day 18 did not differ (P=0.67) between treatment groups but tended to be less (P=0.07) in cows that had PL compared with cows that had no PL. In conclusion, there was no difference in PR and PL between suckled beef cows using 7-d CoSynch or 8-d estradiol-based protocols for synchronization of ovulation and TAI.
- Subjects
OVULATION; CATTLE; PROGESTERONE; ESTRUS; ARTIFICIAL insemination; COWS; MISCARRIAGE; SYNCHRONIZATION
- Publication
Journal of Animal Science, 2022, Vol 100, p346
- ISSN
0021-8812
- Publication type
Academic Journal
- DOI
10.1093/jas/skac247.633