Thompson J A, Marsh W E, Calvin J A, Etherington W G, Momont H W, Kinsel M L
Texas Veterinary Medical Center, Texas A&M University, College Station 77843.
J Dairy Sci. 1994 Nov;77(11):3382-7. doi: 10.3168/jds.S0022-0302(94)77280-5.
The objective of this study was to estimate the effect on calving risk of interval from AI date until scheduled date of pregnancy examination. First AI (n = 7105) from 65 dairy herds in the United States and Canada were followed for 294 d to determine whether cows calved. Calving was modeled as a function of the number of days in the interval, herd, season, and breeding at PGF2 alpha-induced estrus by multivariate logistic regression. The main effects of herd and AI following PGF2 alpha-induced estrus were significantly associated with calving rate from first AI. The main effects of interval and season were not significantly associated with calving.
本研究的目的是评估从人工授精日期至预定妊娠检查日期的间隔对产犊风险的影响。对美国和加拿大65个奶牛场的首次人工授精（n = 7105）进行了294天的跟踪，以确定母牛是否产犊。通过多变量逻辑回归，将产犊建模为间隔天数、牛群、季节以及在PGF2α诱导发情时进行人工授精的函数。牛群以及PGF2α诱导发情后的人工授精的主要效应与首次人工授精后的产犊率显著相关。间隔和季节的主要效应与产犊无显著关联。
