UCD School of Mathematical Sciences, University College Dublin, Belfield, Dublin 4, Ireland.
Vet J. 2012 Apr;192(1):71-4. doi: 10.1016/j.tvjl.2011.04.004. Epub 2011 May 17.
The association between bovine tuberculosis (TB) infection status based on results from the single intradermal comparative tuberculin test (SICTT) and milk production has been described in dairy cows in TB-infected herds in Ireland. The biological basis was uncertain, but could be related to increased TB susceptibility among lower producing dairy cows. In this study, the relationship between somatic cell count (as an objective measure of udder health) and SICTT reactivity (as a proxy for TB infection status) was investigated. Somatic cell counts of TB infected cows, both during and prior to the lactation of diagnosis of TB infection, were examined and compared to non-infected cows. All Irish dairy herds restricted from trading between June 2004 and May 2005 as a result of two or more TB reactors (test positive) to the SICTT were considered for study. Data were collected on 4340 cows from 419 herds. Previous lactation data for the cows were taken into consideration and all lactations on a cow were analysed together with the years of lactations. There was an inherent hierarchical structure in the data, with lactations nested within cows and cows within herds and so a linear mixed model with two random effects was used to describe the data. Milk production (305-day milk yield) was also included in the model as a fixed effect. The results of the study showed that for all lactations and years under investigation, somatic cell counts for SICTT reactor cows when compared to the non-reactor cows were not significantly different. In this study population, TB infection status was not associated with udder health.
在爱尔兰的感染牛结核病（TB）牛群中，曾描述过基于单一皮内比较结核菌素试验（SICTT）结果的牛结核病感染状态与产奶量之间的关联。其生物学基础尚不确定，但可能与产奶量较低的奶牛对结核病的易感性增加有关。在这项研究中，研究了体细胞计数（作为乳房健康的客观衡量标准）与 SICTT 反应性（作为结核病感染状态的替代指标）之间的关系。检查了感染牛在诊断为结核病感染之前和期间的体细胞计数，并将其与未感染的牛进行了比较。所有因 2 头或 2 头以上牛对 SICTT 呈阳性反应（检测呈阳性）而被限制在 2004 年 6 月至 2005 年 5 月之间交易的爱尔兰奶牛群都被认为是研究对象。从 419 个牛群中收集了 4340 头奶牛的数据。考虑了牛以前的泌乳数据，并且将牛的所有泌乳期与泌乳年一起进行了分析。数据具有内在的层次结构，泌乳期嵌套在奶牛中，奶牛嵌套在牛群中，因此使用具有两个随机效应的线性混合模型来描述数据。还将产奶量（305 天产奶量）作为固定效应纳入模型。研究结果表明，在所研究的所有泌乳期和年份中，与非反应牛相比，SICTT 反应牛的体细胞计数没有显着差异。在本研究人群中，结核病感染状态与乳房健康无关。
