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首页> 美国卫生研究院文献>The Journal of Reproduction and Development >Evaluation of criteria for optimal time AI postulated by estrous signs in lactating dairy cows kept in tie-stalls
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Evaluation of criteria for optimal time AI postulated by estrous signs in lactating dairy cows kept in tie-stalls

机译：以发情迹象为基础的泌乳奶牛的最佳时间AI标准的评估

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摘要

Relaxation of the intravaginal part of the uterus is obvious around 6 to 18 h before ovulation, and this is considered the optimal time for artificial insemination (AI), as demonstrated in recent studies. Estrous signs have been suggested as useful criteria for determining the optimal time for AI. Therefore, this study evaluated the usefulness of estrous signs, particularly the relaxation of the intravaginal part of the uterus, as criteria for determining the optimal time for AI. A Total of 100 lactating Holstein-Friesian cows kept in tie-stall barns were investigated. AI was carried out based on the criterion for the optimal time for AI (optimal group), and earlier (early group) and later (late group) than the optimal time for AI, determined on the basis of estrous signs. After AI, ovulation was assessed by rectal palpation and ultrasonographic observation at 6-h intervals. For 87.5% (35/40) of cows in the optimal group, AI was carried out 24-6 h before ovulation, which was previously accepted as the optimal time for AI. AI was carried out earlier (early group) and later (late group) than optimal time for AI in 62.1% (18/29) and 71.0% (22/31) of cows, respectively. The conception rate for the optimal group was 60.0%, and this conception rate was higher than that for the early group (44.8%) and late group (32.2%), without significance. Further, the conception rate of the optimal group was significantly higher than the sum of the conception rates of the early and late groups (38.3%; 23/60) (P < 0.05). These results indicate that the criteria postulated, relaxation of the intravaginal part of the uterus and other estrous signs are useful in determining the optimal time for AI. Furthermore, these estrous signs enable the estimations of stages in the periovulatory period.
机译：子宫内阴道部分的松弛在排卵前约6至18小时很明显，这被认为是人工授精（AI）的最佳时间，如最近的研究所示。已提出发情迹象作为确定AI最佳时间的有用标准。因此，本研究评估了发情体征的有用性，特别是子宫阴道内部分的松弛，作为确定AI最佳时间的标准。总共调查了100个饲养在栏棚中的泌乳荷斯坦奶牛。根据发情体征确定AI的最佳时间的标准（最佳组），比AI的最佳时间早（早期组）和晚（晚期组）进行AI。 AI后，每隔6小时通过直肠触诊和超声检查评估排卵情况。对于最佳组中87.5％（35/40）的母牛，在排卵前24-6 h进行AI，以前被认为是AI的最佳时间。在分别于62.1％（18/29）和71.0％（22/31）的母牛中进行AI最佳时间之前（早期组）和后期（晚期组）进行AI。最佳组的受孕率是60.0％，并且该受孕率高于早期组（44.8％）和晚期组（32.2％），无统计学意义。此外，最佳组的受孕率明显高于早期和晚期组的受孕率之和（38.3％； 23/60）（P <0.05）。这些结果表明，假设的标准，子宫阴道内部分的松弛和其他发情征兆可用于确定AI的最佳时间。此外，这些发情迹象使得可以估计排卵期的阶段。

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