Relationship between the first ovulation within three weeks postpartum and subsequent ovarian cycles and fertility in high producing dairy cows
Relationship between the first ovulation within three weeks postpartum and subsequent ovarian cycles and fertility in high producing dairy cows
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DOI：
10.1262/jrd.18003
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发表时间：
2006-08-01
影响因子：
1.8
通讯作者：
Miyamoto, Akio
中科院分区：
文献类型：
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作者：
Kawashima, Chiho;Kaneko, Etsushi;Miyamoto, Akio
本研究的目的是调查日本北海道高产奶牛产后 3 周内的第一次排卵与随后的卵巢周期和生育力之间的关系。在实验1中，使用110头奶牛（44头初产奶牛和66头经产奶牛）来确定产后3周内第一次排卵对随后卵巢周期的影响。产后 7 至 100 天，每周采集两次乳汁样本。第一次排卵是通过产后 3 周内乳汁黄体酮 (P4) 增加至 1 ng/ml 以上来确定的。产后3周内出现排卵和无排卵的奶牛数量，初产奶牛为31头（70.5%），13头（29.5%），经产奶牛为35头（53.0%），不排卵为31头（47.0%）。根据乳汁 P4 浓度，将产犊后卵巢恢复的模式分为两种类型（正常卵巢周期和异常卵巢周期）。无论产犊数多少，产后 3 周内排卵的奶牛卵巢功能开始正常的时间早于无排卵的奶牛（初产，27.8 天 vs. 44.4 天；多产，30.6 天 vs. 55.7 天；P < 0.01）。在产后 3 周内排卵的多产奶牛中，正常卵巢功能开始后进入正常黄体期的时间早于随后出现异常黄体期的时间（25.5 天 vs. 40.4 天；P < 0.05）。初产奶牛和经产奶牛第一次排卵后乳汁中 P4 浓度均低于第二次排卵后乳汁 P4 浓度（P < 0.05）。在实验2中，使用22头经产奶牛来确定产后3周内第一次排卵对随后生育力的影响。产后 0 至 3 周每周采集一次血样。排卵奶牛从分娩到第一次配种的时间间隔比无排卵奶牛短（68.4 天 vs. 94.8 天；P < 0.05）。产犊后100天的受胎率往往高于无排卵奶牛（50.0% vs. 16.7%，P=0.09）。总之，我们的数据强烈表明，产后3周内排卵是随后恢复卵巢功能和受孕的关键现象，因此可以作为后续生殖性能的指标。
The aim of this study was to investigate the relationship between the first ovulation within 3 weeks postpartum and subsequent ovarian cycles and fertility in high producing dairy cattle in Hokkaido, Japan. In Experiment 1, 110 cows (44 primiparous and 66 multiparous) were used to determine the effects of the first ovulation within 3 weeks postpartum on subsequent ovarian cycles. Milk samples were collected twice weekly from 7 to 100 days postpartum. The first ovulation was identified by an increase in milk progesterone (P4) to more than 1 ng/ml within 3 weeks postpartum. The numbers of cows showing ovulation and anovulation within 3 weeks postpartum were 31 (70.5%) and 13 (29.5%) in the primiparous cows and 35 (53.0%) and 31 (47.0%) in the multiparous cows, respectively. The patterns of ovarian resumption after calving were classified into two types (normal ovarian cycles and abnormal ovarian cycles) on the basis of milk P4 concentrations. Initiation of normal ovarian function in cows ovulated within 3 weeks postpartum occurred earlier than in anovulated cows regardless of the number of calvings (primiparous, 27.8 days vs. 44.4 days; multiparous, 30.6 days vs. 55.7 days; P < 0.01). Out of the multiparous cows that ovulated within 3 weeks postpartum, initiation of normal ovarian function followed by a normal luteal phase was earlier than when it was followed by an abnormal luteal phase (25.5 days vs. 40.4 days; P < 0.05). Milk P4 concentrations after the first ovulation were lower than those after the second ovulation in both the primiparous and multiparous cows (P < 0.05). In Experiment 2, 22 multiparous cows were used to determine the effects of the first ovulation within 3 weeks postpartum on subsequent fertility. Blood samples were collected once a week from 0 to 3 weeks postpartum. The interval from parturition to first service in ovulated cows was shorter than in anovulated cows (68.4 days vs. 94.8 days; P < 0.05). The conception rate by 100 days after calving tended to be higher in ovulated cows than in anovulated cows (50.0% vs. 16.7%, P=0.09). In conclusion, our data strongly suggests that ovulation within 3 weeks postpartum is a crucial phenomenon for subsequent resumption of ovarian function and conception, and thus it can be used as an index of subsequent reproductive performance.