Hockey Cd, Morton Jm, Norman St, McGowan Mr
School of Veterinary Science, The University of Queensland, Brisbane, Qld, Australia.
Reprod Domest Anim. 2010 Oct;45(5):e107-17. doi: 10.1111/j.1439-0531.2009.01531.x.
Two studies were conducted to assess the performance of a commercially available neck-mounted activity meter to detect cows about to ovulate in two paddock-based Holstein-Friesian dairy herds. The activity monitoring system recorded cow activity count in 2-hourly periods. Study I investigated the ability of the system to detect cow ovulatory periods in dairy herds managed in two different Australian environments and breeding systems using five activity alert algorithms. Herd 1 consisted of approximately 130 milking cows calving year-round in a sub-tropical environment and kept in a single dry lot paddock. Herd 2 consisted of approximately 400 milking cows calving seasonally in a temperate climate and fed pasture by rotation through multiple grazing paddocks. Ovulatory periods and non-ovulatory days were identified using milk progesterone monitoring alone or in combination with ovarian ultrasonography; using these 'gold standards' 141 and 135 ovulatory periods were identified in 64 and 135 cows in Herds 1 and 2 respectively. Sensitivity of the activity monitoring system for detecting cow ovulatory periods ranged from 79.4% to 94.1%, specificity from 90.0% to 98.2% and positive predictive value from 35.8% to 75.8%. Study II investigated the ability of the activity meter system to predict the timing of ovulations in paddock-based pasture-fed dairy cattle (Herd 2). The time of ovulation was estimated by repeat trans-rectal ovarian ultrasonography at approximately 0, 12, 24 and 36 h after artificial insemination (AI). The mean times (± SD) from onset and end of increased activity to ovulation were 33.4 ± 12.4 and 17.3 ± 12.8 h respectively (n = 94). Fifty per cent of cows (n = 47) ovulated within the 8-h period between 30 to 38 hs after the onset of increased activity, 76.6% (n = 72) within the 16 h between 24 to 40 h, 85.1% (n = 80) within the 24 h between 18 and 42 h and 90.4% (n = 85) within the 32 h from 19 to 51 h after the onset of increased activity. Results from these studies show that in paddock-based dairy cows in two diverse management systems, this neck-mounted activity meter system detects high proportions of cows that are about to ovulate and provides a useful indication of when ovulation is likely to occur. However, the specificities and positive predictive values using the algorithms assessed may be lower than desirable.
开展了两项研究，以评估一种市售的颈部佩戴式活动监测仪在两个以围场为基础的荷斯坦-弗里生奶牛群中检测即将排卵母牛的性能。该活动监测系统每两小时记录一次奶牛的活动计数。研究I使用五种活动警报算法，调查了该系统在两种不同的澳大利亚环境和繁殖系统中管理的奶牛群中检测排卵周期的能力。牛群1由大约130头全年产犊的泌乳奶牛组成，处于亚热带环境，饲养在一个单一的干栏围场中。牛群2由大约400头季节性产犊的泌乳奶牛组成，处于温带气候，通过轮流在多个放牧围场中放牧来喂养。单独使用牛奶孕酮监测或结合卵巢超声检查来确定排卵周期和非排卵日；使用这些“金标准”，在牛群1和牛群2的64头和135头奶牛中分别确定了141个和135个排卵周期。活动监测系统检测奶牛排卵周期的敏感性范围为79.4%至94.1%，特异性范围为90.0%至98.2%，阳性预测值范围为35.8%至75.8%。研究II调查了活动监测仪系统预测以围场为基础、以牧草喂养的奶牛（牛群2）排卵时间的能力。通过在人工授精（AI）后约0、12、24和36小时重复经直肠卵巢超声检查来估计排卵时间。活动增加开始到结束至排卵的平均时间（±标准差）分别为33.4±12.4小时和17.3±12.8小时（n = 94）。50%的奶牛（n = 47）在活动增加开始后的30至38小时内的8小时时间段内排卵，76.6%（n = 72）在24至40小时的16小时内排卵，85.1%（n = 80）在18至42小时的24小时内排卵，90.4%（n = 85）在活动增加开始后的19至51小时的32小时内排卵。这些研究结果表明，在两种不同管理系统的以围场为基础的奶牛中，这种颈部佩戴式活动监测仪系统能检测出很大比例即将排卵的奶牛，并能提供排卵可能发生时间的有用指示。然而，使用评估的算法得出的特异性和阳性预测值可能低于理想水平。
