Laboratory of Theriogenology, Department of Veterinary Clinical Sciences, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan.
Anim Sci J. 2009 Dec;80(6):649-54. doi: 10.1111/j.1740-0929.2009.00694.x.
Estrous expressions in dairy cows have been shortened and weakened. Dairy heifers, on the other hand, may not have had such changes in estrous signs as observed in cows, since they have less stresses than cows. The aim of this study was to describe the duration of estrus in a herd of dairy heifers. A total of 56 Holstein Friesian heifers estrus was synchronized using two different hormonal protocols. They were checked for primary and secondary estrous signs with the help of heat detection devices for 48 h at an interval of 4 h starting at 16.00 hour, one day after PGF(2alpha) treatment. Onset and end of standing estrus during 48 h observation period was recorded in 35 of the 44 heifers coming into estrus within 5 days after PGF(2alpha) treatment during the observation period. The duration of standing estrus on the average (+/-SD) was 9.7 +/- 5.3 h. Percentage of heifers with standing estrus longer than 12 h was 40%, and 53% showed standing estrus only for 4-8 h. It is indicated that duration of estrus in dairy heifers has been shortened recently.
奶牛的发情表现已经缩短和减弱。另一方面，奶牛发情的表现可能在奶牛身上观察不到，因为奶牛的压力较小。本研究旨在描述奶牛场中奶牛发情的持续时间。使用两种不同的激素方案对 56 头荷斯坦弗里森奶牛进行发情同步处理。在 PGF(2alpha)处理后一天，从 16.00 小时开始，每 4 小时间隔检查一次主要和次要发情症状，持续 48 小时。在观察期内，有 44 头奶牛在 PGF(2alpha)处理后 5 天内发情，其中 35 头记录了发情期 48 小时内的站立发情开始和结束时间。站立发情的平均（+/-SD）持续时间为 9.7 +/- 5.3 小时。站立发情时间超过 12 小时的奶牛比例为 40%，4-8 小时站立发情的奶牛比例为 53%。这表明，奶牛发情的持续时间最近已经缩短了。
