Xu Z Z, McKnight D J, Vishwanath R, Pitt C J, Burton L J
Livestock Improvement Corporation Ltd., Hamilton, New Zealand.
J Dairy Sci. 1998 Nov;81(11):2890-6. doi: 10.3168/jds.S0022-0302(98)75849-7.
The efficiency and accuracy of estrus detection using HeatWatch (DDx Inc., Denver, CO) or visual observation were compared in an autumn-calving Friesian herd (n = 48 per group) and a spring-calving Jersey herd (n = 50 per group) grazing on pasture. Cows in the group monitored by the HeatWatch system were fitted with a pressure-sensitive transmitter that signaled mounting activities associated with estrus. Visual observation was carried out for about 20 min before the morning and afternoon milkings and was aided by a strip of paint applied over the tailhead. Ovarian cyclicity was monitored with progesterone concentrations in milk samples collected twice a week. The efficiency and accuracy of estrus detection were, respectively, 98.4 and 97.6% for visual observation and 91.7 and 100% for HeatWatch detection. Autumn-calving herds differed from spring-calving herds in duration of estrus (9.7 vs. 7.3 h), number of mounts (13.6 vs. 8.5), total duration of mounts (36.8 vs. 19.9 s), and mean duration of a mount (2.6 vs. 2.3 s). There was no significant variation in the distribution of the time of onset of estrus or mounting activities at different hours of the day. Conception rate was similar for AI after estrus detection with HeatWatch (65.8%) or after visual observation (65.0%). The highest conception rate was obtained when AI was carried out between 12 and 18 h after the first mount. Both the HeatWatch system and visual observation plus tail painting can be used for estrus detection of dairy cows on pasture.
在一个秋季产犊的弗里斯兰牛群（每组48头）和一个春季产犊的泽西牛群（每组50头）中，比较了使用HeatWatch（DDx公司，科罗拉多州丹佛市）或视觉观察进行发情检测的效率和准确性。这两个牛群都在牧场放牧。由HeatWatch系统监测的组中的母牛佩戴了一个压敏发射器，该发射器会发出与发情相关的爬跨活动信号。在上午和下午挤奶前约20分钟进行视觉观察，并通过在牛尾根部涂抹一条颜料来辅助观察。通过每周采集两次牛奶样本中的孕酮浓度来监测卵巢周期性。视觉观察的发情检测效率和准确性分别为98.4%和97.6%，HeatWatch检测的效率和准确性分别为91.7%和100%。秋季产犊的牛群与春季产犊的牛群在发情持续时间（9.7小时对7.3小时）、爬跨次数（13.6次对8.5次）、总爬跨持续时间（36.8秒对19.9秒）以及单次爬跨平均持续时间（2.6秒对2.3秒）方面存在差异。一天中不同时间发情开始或爬跨活动的分布没有显著差异。使用HeatWatch检测发情后进行人工授精的受胎率（65.8%）与视觉观察后进行人工授精的受胎率（65.0%）相似。在首次爬跨后12至18小时进行人工授精时获得了最高受胎率。HeatWatch系统以及视觉观察加尾根涂漆都可用于牧场奶牛的发情检测。
