Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
J Dairy Sci. 2010 Nov;93(11):5179-87. doi: 10.3168/jds.2010-3234.
The objective of this study was to determine the contribution of cow factors to the probability of a successful first insemination (SFI). The investigation was performed with 51,791 lactations from 1,396 herds obtained from the Dutch dairy cow database of the Cattle Improvement Co-operative (CRV). Cows that had the first insemination (AI) between 40 and 150 d postpartum were selected. The first AI was classified as successful when cows were not reinseminated and either calved between 267 and 295 d later or were culled within 135 to 295 d after first AI. The lactation curve characteristics of individual lactations were estimated by Wilmink's curve using the test-day milk records from CRV. The lactation curve characteristics (peak milk yield, milk yield at the first-AI date, time of peak yield (PT), and milk persistency) were calculated. Breed, parity, interval from calving to first AI (CFI), lactation curve characteristics, milk production traits, moment of AI related to PT (before or after PT), calf status, month of AI, and month of calving were selected as independent variables for a model with SFI as a dependent variable. A multivariable logistic regression model was used with farm as a random effect. Overall SFI was 44%. The effect of parity on SFI depended on CFI. The first-parity cows had the greatest SFI (0.43) compared with other parities (0.32-0.39) at the same period of CFI before 60 d in milk (DIM), and cows in parity ≥5 had the least SFI (0.38-0.40) when AI was after 60 DIM. After 60 DIM, extending CFI did not improve SFI in the first-parity cows, but SFI was improved in multiparous cows. Holstein-Friesian cows had lesser SFI (0.37) compared with cross-breed cows (0.39-0.46). Twin and stillbirth calving reduced SFI (0.39) compared with a single female calf (0.45) or a male calf (0.43) calving. The SFI in different months of AI varied and depended on CFI. Cows that received AI before 60 DIM had a lesser SFI, especially in March, June, and July (0.18, 0.35, and 0.34, respectively). Artificial insemination before PT reduced SFI (0.39) in comparison with AI after PT (0.44). The effect of milk yield at the first-AI date on SFI varied depending on CFI. After 60 DIM at the same period of CFI, a high level of milk yield at the first-AI date reduced SFI. In conclusion, knowledge of the contribution of cow factors on SFI can be applied to support decision making on the moment of insemination of an individual cow in estrus.
本研究旨在确定奶牛因素对首次配种（SFI）成功概率的贡献。该研究使用了荷兰奶牛数据库（CRV）中的 51791 个泌乳期和 1396 个牛群的数据进行。选择产后 40 至 150 天之间进行首次配种（AI）的奶牛。当奶牛未再次配种且在 267 至 295 天后分娩或在首次 AI 后 135 至 295 天内被淘汰时，将首次 AI 分类为成功。使用 CRV 的测试日牛奶记录，通过 Wilmink 曲线估计个体泌乳期的泌乳曲线特征。计算泌乳曲线特征（高峰产奶量、首次 AI 日期的产奶量、高峰产奶量时间（PT）和产奶持续时间）。选择品种、胎次、产后至首次 AI 的间隔（CFI）、泌乳曲线特征、产奶性状、与 PT 相关的 AI 时间（PT 之前或之后）、犊牛状态、AI 月份和产犊月份作为与 SFI 作为因变量的模型的自变量。使用包含农场作为随机效应的多变量逻辑回归模型。总体 SFI 为 44%。胎次对 SFI 的影响取决于 CFI。与其他胎次（0.32-0.39）相比，第一胎次奶牛在泌乳期前 60 天（DIM）的同一 CFI 时期具有最大的 SFI（0.43），而在产后 60 天 DIM 后进行 AI 的奶牛具有最小的 SFI（0.38-0.40）。在产后 60 天 DIM 之后，延长 CFI 并没有提高第一胎次奶牛的 SFI，但在多胎次奶牛中提高了 SFI。荷斯坦-弗里生奶牛的 SFI（0.37）低于杂交奶牛（0.39-0.46）。双胞胎和死产犊牛降低了 SFI（0.39），而单胎雌性犊牛（0.45）或雄性犊牛（0.43）的产犊降低了 SFI。不同 AI 月份的 SFI 不同，取决于 CFI。在产后 60 天 DIM 之前进行 AI 的奶牛的 SFI 较低，尤其是在 3 月、6 月和 7 月（分别为 0.18、0.35 和 0.34）。与 PT 后 AI（0.44）相比，PT 前 AI（0.39）降低了 SFI。首次 AI 日期的产奶量对 SFI 的影响取决于 CFI。在同一 CFI 时期的产后 60 天 DIM 之后，首次 AI 日期的高产奶量降低了 SFI。总之，奶牛因素对 SFI 的贡献的知识可以应用于支持个体奶牛发情期配种时间的决策。
