Effect of estrous expression on timing and failure of ovulation of Holstein dairy cows using automated activity monitors
Effect of estrous expression on timing and failure of ovulation of Holstein dairy cows using automated activity monitors
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DOI：
10.3168/jds.2018-15151
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发表时间：
2018-12-01
影响因子：
3.5
通讯作者：
Cerri, Ronaldo L. A.
中科院分区：
文献类型：
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作者：
Burnett, Tracy A.;Polsky, Liam;Cerri, Ronaldo L. A.
本研究的目的是确定通过自动活动监测器 (AAM) 测量的动情表达是否会影响泌乳荷斯坦奶牛的排卵时间和排卵失败。奶牛在产后 10 天前配备 2 个 AAM，其中 1 个颈部安装 (AAM(c)) 和 1 个腿部安装 (AAM(L))，并在其活动超过 AAM(c) 的警报阈值时参加试验。本研究共使用了 293 头不同奶牛的 850 次发情期。当奶牛被登记时，通过经直肠超声检查对它们的卵巢进行扫描，并对步态和身体状况进行评分。对发情奶牛的卵巢进行扫描，每天两次，最多持续3天，以确定排卵前卵泡（排卵）的消失情况，并计算从发情到排卵的时间间隔。 AAM 记录的体力活动数据用于通过 2 个特征来确定发情行为：(1) 峰值活动和 (2) 持续时间。峰值活动仅适用于 AAM(L)。峰值活动定义为发情期间的最大活动。发情持续时间定义为奶牛的活动超过 AAM 软件设定的阈值的时间。 AAM(c) 正确识别了 87.8% 的发情警报，误报率为 12.2%。 AAM(c) 和 AAM(L) 从活动警报到排卵的平均间隔（+/- 标准差）分别为 25.8 +/- 10.2 和 24.7 +/- 9.3 小时。动情表达的变化与从警觉到排卵的间隔差异相关。使用 AAM(c) 发现，排卵间隔短的奶牛比中排卵间隔和长排卵间隔的奶牛发情表达较弱，而使用 AAM(L) 时，排卵间隔短的奶牛比排卵间隔中的奶牛表现出较弱的动情表达，但与排卵间隔长的奶牛相同。此外，与动情表达较高的发情事件相比，无论 AAM 为何，发情表达较少的发情事件具有短排卵间隔（低于中位数 20 小时）的几率增加（AAM(c) 和 AAM(L) 的几率分别增加 2.6 和 1.9）。排卵失败受到动情表达的影响，因为与动情表达较少的发情事件相比，峰值活动较大或持续时间较长的发情事件减少了排卵失败（AAM（c）峰值活动：1.9 +/- 1.4 vs. 9.5 +/- 1.7%；AAM（L）峰值活动：2.3 +/- 1.4 vs. 6.2 +/- 1.5%；AAM（c）持续时间：2.1 +/- 1.4 与 8.9 +/- 1.7%）。此外，在 AAM(c)（42.3 +/- 0.4 vs. 31.7 +/- 0.4%）和 AAM（L）（43.1 +/- 0.4 vs. 36.3 +/- 0.4%）的情况下，发情表达较多的奶牛每次人工授精的妊娠率高于发情表达较少的奶牛。即使剔除未能排卵的奶牛，每次人工授精的妊娠结果也是一致的。总之，使用 2 种不同的 AAM 时，发情表达与排卵时间、排卵失败和生育力高度相关。发情表达较高的奶牛从活动警觉到排卵的时间间隔较长，排卵失败的情况较少，并且每次人工授精的妊娠率较高。
The aim of this study was is to determine if estrous expression, as measured by an automated activity monitor (AAM), affects timing and failure of ovulation of lactating Holstein dairy cows. Cows were equipped with 2 AAM, 1 neck-mounted (AAM(c) ) and 1 leg-mounted (AAM(L)), by 10 d postpartum and enrolled into the trial when their activity crossed the alert threshold on the AAM(c). A total of 850 episodes of estrus from 293 different cows were used for this study. When cows were enrolled, their ovaries were scanned by transrectal ultrasonography and gait and body condition scored. Ovaries of cows detected in estrus were scanned twice daily for a maximum of 3 d to determine the disappearance of the preovulatory follicle (ovulation) and the interval from estrus to ovulation was calculated. Physical activity data recorded from the AAM were used to determine estrus behavior using 2 traits: (1) peak activity and (2) duration. Peak activity was only available for the AAM(L). Peak activity was defined as the maximum activity during an estrus episode. Duration of estrus was defined as the time the activity of the cow exceeded threshold values set by the AAM software. The AAM(c) correctly identified 87.8% of the estrus alerts, with 12.2% false positives. The average (+/- standard deviation) intervals from activity alert to ovulation were 25.8 +/- 10.2 and 24.7 +/- 9.3 h for the AAM(c) and AAM(L), respectively. Changes in estrous expression were associated with differences in the interval from alert to ovulation. Cows with short intervals to ovulation were found to have less intense estrous expression than cows with medium and long length intervals to ovulation using the AAM(c), whereas using the AAM(L), cows with short intervals to ovulation exhibited less intense estrous expression than cows with medium but the same as those with long intervals to ovulation. Furthermore, irrespective of the AAM, estrus events with less estrous expression had increased odds of having a short interval to ovulation (below the median of 20 h) when compared with those having greater estrous expression (2.6 and 1.9 increased odds for the AAM(c) and AAM(L), respectively). Ovulation failure was affected by estrous expression because estrus events with greater peak activity or longer duration had reduced ovulation failure compared with those with less estrous expression (AAM(c) peak activity: 1.9 +/- 1.4 vs. 9.5 +/- 1.7%; AAM(L) peak activity: 2.3 +/- 1.4 vs. 6.2 +/- 1.5%; AAM(c) duration: 2.1 +/- 1.4 vs. 8.9 +/- 1.7%). In addition, cows with more estrous expression had greater pregnancy per artificial insemination than those with less estrous expression with both the AAM(c) (42.3 +/- 0.4 vs. 31.7 +/- 0.4%) and the AAM(L) (43.1 +/- 0.4 vs. 36.3 +/- 0.4%). Pregnancy per artificial insemination results were consistent even when removing cows that failed to ovulate. In conclusion, expression of estrus was highly associated with ovulation timing, ovulation failure, and fertility when using 2 different AAM. Cows with greater estrous expression have longer intervals from activity alert to ovulation, experience less ovulation failure, and have greater pregnancy per artificial insemination.