Hirata Toh-Ichi, Sato Mai, Sasaki Shu-Ichi, Sasaki Osamu, Osawa Takeshi
Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka, Japan.
J Reprod Dev. 2008 Oct;54(5):346-51. doi: 10.1262/jrd.20007. Epub 2008 Jul 7.
We investigated whether suckling would affect embryo production of cows bred by timed artificial insemination (TAI) following an ovulation synchronization protocol combined with ovum pick-up and progesterone releasing intravaginal device (OPU-PRID-TAI protocol). The number of oocytes and transferable embryos collected by repeated OPU, performed before and after TAI, were recorded. A total of 14 Japanese Black cows were divided into weaned (n=7) and suckled groups (n=7). All 14 cows were treated with OPU on day 0 (the first day of treatment) and then with a PRID for 9 days. Prostaglandin F(2alpha) analog was administered on day 7, GnRH analog was administered on day 10 (36 h after removal of the PRID) and TAI was performed 12 h later. Ovulation was confirmed by palpation per rectum the following day. After TAI, additional OPU sessions were performed on days 18, 25 and 32. The synchronized ovulation rates of the weaned and suckled groups were 100 and 85.7%, and the conception rates were 71.4 and 42.9%, respectively. Immature oocytes were fertilized and cultured in vitro. The numbers of oocytes collected and blastocysts generated were similar between the individual OPU sessions in both groups. However, the total numbers of oocytes collected, cultured oocytes, cleavage embryos and blastocysts as well as the proportions of cleavage embryos and blastocysts to cultured oocytes were all significantly (P<0.05) greater in the weaned group compared with the suckled group. These results suggest that the OPU-PRID-TAI protocol has the potential to produce a significant number of good-quality embryos in vitro after repeated OPU in early postpartum weaned Japanese Black cows. To collect more oocytes and produce more embryos, we suggest that calves be removed from cows scheduled for treatment using this protocol.
我们研究了在排卵同步方案结合采卵和孕酮释放阴道内装置（OPU-PRID-TAI方案）后，哺乳是否会影响定时人工授精（TAI）繁育的奶牛的胚胎生产。记录了在TAI前后通过重复OPU收集的卵母细胞和可移植胚胎的数量。将14头日本黑牛分为断奶组（n = 7）和哺乳组（n = 7）。所有14头牛在第0天（治疗第一天）接受OPU治疗，然后使用PRID 9天。在第7天给予前列腺素F（2α）类似物，在第10天（去除PRID后36小时）给予GnRH类似物，并在12小时后进行TAI。第二天通过直肠触诊确认排卵。TAI后，在第18、25和32天进行额外的OPU操作。断奶组和哺乳组的同步排卵率分别为100%和85.7%，受孕率分别为71.4%和42.9%。未成熟卵母细胞进行体外受精和培养。两组各次OPU操作收集的卵母细胞数量和产生的囊胚数量相似。然而，断奶组收集的卵母细胞总数、培养的卵母细胞、分裂胚胎和囊胚数量，以及分裂胚胎和囊胚占培养卵母细胞的比例均显著（P<0.05）高于哺乳组。这些结果表明，OPU-PRID-TAI方案有潜力在产后早期断奶的日本黑牛重复OPU后体外产生大量优质胚胎。为了收集更多卵母细胞并产生更多胚胎，我们建议将犊牛从计划使用该方案治疗的奶牛中移除。
