Alnimer M A, Tabbaa M J, Ababneh M M, Lubbadeh W F
Department of Animal Production, Faculty of Agriculture, University of Jordan, Amman, Jordan.
Theriogenology. 2009 Sep 15;72(5):731-40. doi: 10.1016/j.theriogenology.2009.05.006. Epub 2009 Jun 30.
Two modifications of the Ovsynch protocol, GnRH+TAI after PGF(2 alpha) 48 h (CO-48) or 72 h (CO-72), were compared with the original protocol (OVS: GnRH-7 d-PGF(2 alpha)-2 d-GnRH-16 h-TAI) to study their effects on reproductive performance in 785 lactating dairy cows (Holstein Friesian, Bos Taurus). Results showed that more cows (P<0.001) returned to estrus within a week after TAI with CO-48 treatment compared with that in OVS and CO-72 treatments. Pregnancy rates were greater (P<0.001) for the CO-72 cows than those for both OVS and CO-48 treatments and for primiparous cows compared with multiparous cows. Moreover, pregnancy rates were lower in summer compared with those in winter. Pregnancy losses for cows in both CO-48 and CO-72 were greater (P<0.05) than that for cows in OVS treatment. Pregnancy losses were greater in summer (P<0.001) than in winter and for multiparous cows (P<0.001) than for primiparous cows. In conclusion, primiparous and winter-bred cows had greater pregnancy rates and fewer pregnancy losses than those of multiparous cows and summer-bred cows, respectively. Because of the presence of significant treatment, parity, and season interactions, TAI with ovulation synchronization protocols should be tailored according to the season and parity. CO-72 is recommended for primiparous cows but not for multiparous cows, and CO-48 is not recommended for synchronization. Furthermore, cows that exhibited estrus at any time were inseminated to improve pregnancy rates in ovulation synchronization protocols.
将Ovsynch方案进行了两种修改，即PGF(2α) 48小时（CO-48）或72小时（CO-72）后进行GnRH+定时人工授精（TAI），并与原始方案（OVS：GnRH-7天-PGF(2α)-2天-GnRH-16小时-TAI）进行比较，以研究它们对785头泌乳奶牛（荷斯坦弗里生牛，Bos Taurus）繁殖性能的影响。结果显示，与OVS和CO-72处理相比，CO-48处理的奶牛在TAI后一周内发情的更多（P<0.001）。CO-72处理的奶牛妊娠率高于OVS和CO-48处理的奶牛，初产奶牛的妊娠率高于经产奶牛（P<0.001）。此外，夏季的妊娠率低于冬季。CO-48和CO-72处理的奶牛妊娠损失均高于OVS处理的奶牛（P<0.05）。夏季的妊娠损失高于冬季（P<0.001），经产奶牛的妊娠损失高于初产奶牛（P<0.001）。总之，初产奶牛和冬季配种的奶牛分别比经产奶牛和夏季配种的奶牛妊娠率更高、妊娠损失更少。由于存在显著的处理、胎次和季节交互作用，定时人工授精的排卵同步方案应根据季节和胎次进行调整。建议初产奶牛采用CO-72方案，但经产奶牛不适用，CO-48不推荐用于同步发情。此外，对任何时间发情的奶牛进行授精，以提高排卵同步方案中的妊娠率。
