Livestock Systems Research Department, Teagasc, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork, P61C 996, Ireland.
Livestock Systems Research Department, Teagasc, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork, P61C 996, Ireland.
J Dairy Sci. 2017 Sep;100(9):7468-7477. doi: 10.3168/jds.2017-12749. Epub 2017 Jul 12.
The effect of the Mycobacterium avium ssp. paratuberculosis (MAP) ELISA status on test-day milk performance of cows from Irish herds enrolled in the pilot national voluntary Johne's disease control program during 2013 to 2015 was estimated. A data set comprising 92,854 cows and 592,623 complete test-day records distributed across 1,700 herds was used in this study. The resulting ELISA outcome (negative, inconclusive, and positive) of each cow within each year of the program was used to allocate the cow into different scenarios representing the MAP status. At MAPscenario, all cows testing ELISA nonnegative (i.e., inconclusive and positive) were assigned a MAP-positive status; at MAPscenario only cows testing ELISA-positive were assigned a MAP-positive status; at MAPscenario only cows testing ELISA nonnegative (inconclusive or positive) and gathered exclusively from herds where at least 2 further ELISA nonnegative (inconclusive or positive) cows were found were assigned a MAP-positive status; at MAPscenario only cows testing ELISA-positive that were gathered exclusively from herds where at least 2 further ELISA-positive cows were found were assigned a MAP-positive status. Milk outputs based on test-day records were standardized for fat and protein contents (SMY) and the effect of MAP ELISA status on the SMY was estimated by a linear mixed effects model structure. The SMY mean difference recorded at test day between cows with a MAP-positive status and those with a MAP-negative status within MAPscenario was estimated at -0.182 kg/test day; the mean difference was -0.297 kg/test day for MAPscenario; for MAPscenario mean difference between MAP-positive status and MAP test-negative cows was -0.209 kg/test day, and for MAPscenario, the difference was -0.326 kg/test day.
本研究估计了 2013 年至 2015 年期间参加爱尔兰试点国家自愿性约翰氏病控制计划的牛群中分枝杆菌 avium ssp. paratuberculosis（MAP）ELISA 状态对奶牛测试日产奶性能的影响。该研究使用了一个包含 92854 头奶牛和 592623 个完整测试日记录的数据集，分布在 1700 个牛群中。该计划每一年中每头奶牛的 ELISA 结果（阴性、不确定和阳性）用于将奶牛分配到不同的代表 MAP 状态的方案中。在 MAPscenario 中，所有 ELISA 检测非阴性（即不确定和阳性）的奶牛均被分配为 MAP 阳性状态；在 MAPscenario 中，只有 ELISA 阳性的奶牛被分配为 MAP 阳性状态；在 MAPscenario 中，只有 ELISA 检测非阴性（不确定或阳性）且仅从至少发现 2 头其他 ELISA 检测非阴性（不确定或阳性）奶牛的牛群中采集的奶牛被分配为 MAP 阳性状态；在 MAPscenario 中，仅从至少发现 2 头其他 ELISA 阳性奶牛的牛群中采集的 ELISA 阳性奶牛被分配为 MAP 阳性状态。基于测试日记录的奶产量标准化了脂肪和蛋白质含量（SMY），并通过线性混合效应模型结构估计了 MAP ELISA 状态对 SMY 的影响。在 MAPscenario 中，MAP 阳性状态和 MAP 阴性状态奶牛之间在测试日记录的 SMY 平均差异估计为-0.182kg/测试日；在 MAPscenario 中，平均差异为-0.297kg/测试日；在 MAPscenario 中，MAP 阳性状态和 MAP 测试阴性奶牛之间的平均差异为-0.209kg/测试日，在 MAPscenario 中，差异为-0.326kg/测试日。
