Lescourret F, Coulon J B, Faye B
Laboratoire d'Ecopathologie, Institut National de la Recherche Agronomique, Champanelle, France.
J Dairy Sci. 1995 Oct;78(10):2167-77. doi: 10.3168/jds.S0022-0302(95)76844-8.
Mastitis occurrence within a lactation and times of mastitis onset were studied for about 1000 cows. The number of mastitis cases within a lactation was modeled through overdispersed Poisson regression with individual and herd covariants. The results emphasized the role of the herd variable. Increased production potential increased the number of cases per lactation at a rate of 1.4/10 kg. Calving month also played an important role. The incidence of mastitis was greater when calving took place in early autumn or winter, which led to an expanded housing period. The interval from calving to the first case of mastitis and the intervals between successive cases were modeled for cases occurring during lactation through random selections from fitted gamma distributions, these distributions being truncated to consider the lactation length. The results of both steps can be used to simulate mastitis occurrence in different conditions.
对约1000头奶牛的一个泌乳期内的乳腺炎发生情况及乳腺炎发病时间进行了研究。通过具有个体和畜群协变量的过度分散泊松回归对一个泌乳期内的乳腺炎病例数进行建模。结果强调了畜群变量的作用。生产潜力的提高使每泌乳期的病例数增加，增加速率为每10千克产奶量增加1.4例。产犊月份也起着重要作用。当产犊发生在初秋或冬季时，乳腺炎的发病率更高，这导致了更长的圈舍饲养期。通过从拟合的伽马分布中随机选择，对泌乳期内发生的病例从产犊到第一例乳腺炎的间隔以及连续病例之间的间隔进行建模，这些分布被截断以考虑泌乳期长度。这两个步骤的结果可用于模拟不同条件下的乳腺炎发生情况。
