Gentry G T, Walker R S, Gentry L R
Idlewild Research Station, Louisiana State University Agricultural Center, 4419 Idlewild Road, Clinton, LA 70722, United States.
Hill Farm Research Station, Louisiana State University Agricultural Center, 11959 Highway 9, Homer, LA 71040, United States.
Anim Reprod Sci. 2016 May;168:19-25. doi: 10.1016/j.anireprosci.2016.02.021. Epub 2016 Feb 27.
One-hundred-eighty crossbred beef cows and 66 crossbred beef heifers across three locations were stratified by body weight (BW), body condition score (BCS), and age (within location) to evaluate administration of follicle stimulating hormone (FSH) on Day 2 using a modified 7-day CO-Synch plus CIDR(®) protocol (Day 0=CIDR insertion) with timed-artificial insemination (TAI) at 72 h (cows) or 54 h (heifers) following CIDR removal. Estrous response following CIDR removal was determined using an Estrotect patch and TAI and final pregnancy rates were determined by transrectal ultrasonography 42-45 days following TAI and ≥ 45 days following removal of clean-up bulls. Estrous response rate, TAI and final pregnancy rates for cows were not affected (P ≥ 0.65) by treatment. Cows that exhibited estrus had greater (P<0.01) TAI pregnancy rate (66%) than cows not exhibiting estrus (38%). There was an estrous response by postpartum length interaction (P=0.02) where cows exhibiting estrus and ≥ 55 days postpartum had greater TAI pregnancy rates (75%) compared to cows not exhibiting estrus and < 55 days postpartum (39%) or ≥ 55 days postpartum (28%). For heifers, timed AI (P=0.46) and final pregnancy rates (P=0.45) were similar across treatments and estrous response had no effect (P=0.30) on TAI pregnancy rates. In conclusion, the addition of FSH to the CO-Synch plus CIDR estrous synchronization protocol did not increase TAI pregnancy rates in beef cows or heifers. However, a positive estrous response to the synchronization protocol was associated with increased TAI pregnancy rates in cows.
在三个地点的180头杂交肉牛母牛和66头杂交肉牛小母牛，根据体重（BW）、体况评分（BCS）和年龄（在同一地点内）进行分层，以评估在第2天使用改良的7天同期发情+阴道孕酮释放装置（CIDR）方案（第0天=插入CIDR），并在取出CIDR后72小时（母牛）或54小时（小母牛）进行定时人工授精（TAI）时促卵泡激素（FSH）的给药情况。使用发情检测贴片和TAI确定取出CIDR后的发情反应，通过直肠超声检查在TAI后42 - 45天以及清除公牛后≥45天确定最终妊娠率。处理对母牛的发情反应率、TAI和最终妊娠率没有影响（P≥0.65）。表现出发情的母牛的TAI妊娠率（66%）高于未表现出发情的母牛（38%）（P<0.01）。存在产后时长与发情反应的交互作用（P = 0.02），其中产后≥55天且表现出发情的母牛的TAI妊娠率（75%）高于未表现出发情且产后<55天（39%）或产后≥55天（28%）的母牛。对于小母牛，各处理间定时人工授精率（P = 0.46）和最终妊娠率（P = 0.45）相似，发情反应对TAI妊娠率没有影响（P = 0.30）。总之，在同期发情+CIDR发情同步方案中添加FSH并没有提高肉牛母牛或小母牛的TAI妊娠率。然而，对同步方案出现阳性发情反应与母牛TAI妊娠率的提高相关。
