Institut für Tierzucht und Haustiergenetik, Justus-Liebig-Universität, Gießen, Germany.
J Dairy Sci. 2012 May;95(5):2734-9. doi: 10.3168/jds.2011-4994.
The objective of this study was to estimate genetic manifestation of Mycobacterium avium ssp. paratuberculosis (MAP) infection in German Holstein cows. Incorporated into this study were 11,285 German Holstein herd book cows classified as MAP-positive and MAP-negative animals using fecal culture results and originating from 15 farms in Thuringia, Germany involved in a paratuberculosis voluntary control program from 2008 to 2009. The frequency of MAP-positive animals per farm ranged from 2.7 to 67.6%. The fixed effects of farm and lactation number had a highly significant effect on MAP status. An increase in the frequency of positive animals from the first to the third lactation could be observed. Threshold animal and sire models with sire relationship were used as statistical models to estimate genetic parameters. Heritability estimates of fecal culture varied from 0.157 to 0.228. To analyze the effect of prevalence on genetic parameter estimates, the total data set was divided into 2 subsets of data into farms with prevalence rates below 10% and those above 10%. The data set with prevalence above 10% show higher heritability estimates in both models compared with the data set with prevalence below 10%. For all data sets, the sire model shows higher heritabilities than the equivalent animal model. This study demonstrates that genetic variation exists in dairy cattle for paratuberculosis infection susceptibility and furthermore, leads to the conclusion that MAP detection by fecal culture shows a higher genetic background than ELISA test results. In conclusion, fecal culture seems to be a better trait to control the disease, as well as an appropriate feature for further genomic analyses to detect MAP-associated chromosome regions.
本研究旨在估计分枝杆菌 avium ssp. 副结核病（MAP）感染在德国荷斯坦奶牛中的遗传表现。纳入本研究的是 11285 头德国荷斯坦牛，这些牛是根据粪便培养结果分类为 MAP 阳性和 MAP 阴性动物的，它们来自德国图林根州的 15 个农场，这些农场参与了 2008 年至 2009 年的副结核病自愿控制计划。每个农场 MAP 阳性动物的频率从 2.7%到 67.6%不等。农场和泌乳次数的固定效应对 MAP 状态有高度显著影响。从第一泌乳期到第三泌乳期，阳性动物的频率增加。使用阈值动物和有亲缘关系的 sire 模型作为统计模型来估计遗传参数。粪便培养的遗传力估计值在 0.157 到 0.228 之间。为了分析流行率对遗传参数估计的影响，将总数据集分为 2 个子数据集，一个是流行率低于 10%的农场，另一个是流行率高于 10%的农场。流行率高于 10%的数据集中，两种模型的遗传力估计值都高于流行率低于 10%的数据集中。对于所有数据集， sire 模型的遗传力都高于等效的动物模型。本研究表明，奶牛对副结核病感染易感性存在遗传变异，此外，还得出结论，粪便培养法检测 MAP 比 ELISA 检测结果具有更高的遗传背景。总之，粪便培养似乎是控制该疾病的更好特征，也是进一步进行基因组分析以检测与 MAP 相关的染色体区域的合适特征。
