Kudahl A B, Nielsen S S
Faculty of Agricultural Sciences, Department of Animal Health, Welfare and Nutrition, University of Aarhus, Tjele, Denmark.
J Dairy Sci. 2009 Sep;92(9):4340-6. doi: 10.3168/jds.2009-2039.
The effect of infection with Mycobacterium avium ssp. paratuberculosis (MAP) on slaughter weight and slaughter value of dairy cows was evaluated. Two data sets were analyzed: 1) recordings from 1,031 cows from herds in a pilot study to control MAP infections, and 2) recordings from 36,455 cows from herds participating in the Danish MAP control program. The effect of stage of MAP infection on carcass weight and slaughter value was assessed by ANOVA. Infection stage was diagnosed by repeated milk antibody ELISA in both data sets. Furthermore, repeated fecal culture was recorded in data set 1 and occurrence of enteritis or enteric edema found at slaughter was recorded in data sets 1 and 2. Compared with presumably unaffected cows with at least 2 ELISA negative tests, slaughter weight and value were reduced by 10 and 17%, respectively, in cows with positive ELISA at slaughter. If the cow was also positive using fecal culture, slaughter weight and value were reduced up to 15 and 31%, respectively. The slaughter weight and value were reduced an additional 20 and 31%, respectively, for cases with recorded enteritis or edema. Thereby, summarized weight losses of up to 31% and slaughter value losses up to 48% occurred. Cows with negative fecal cultures had reduced slaughter results only if they were ELISA-positive in the last 2 tests. Losses of both slaughter weight and slaughter value caused by MAP were more severe than previously estimated. These losses could be predicted by repeated milk ELISA tests with or without confirmation with fecal culture.
评估了副结核分枝杆菌（MAP）感染对奶牛屠宰体重和屠宰价值的影响。分析了两个数据集：1）来自一项控制MAP感染的试点研究中牛群的1031头奶牛的记录，以及2）来自参与丹麦MAP控制计划的牛群的36455头奶牛的记录。通过方差分析评估MAP感染阶段对胴体重量和屠宰价值的影响。在两个数据集中均通过重复的牛奶抗体ELISA诊断感染阶段。此外，在数据集1中记录了重复的粪便培养情况，在数据集1和2中记录了屠宰时发现的肠炎或肠水肿情况。与至少有2次ELISA阴性检测结果的推测未受影响的奶牛相比，屠宰时ELISA呈阳性的奶牛的屠宰体重和价值分别降低了10%和17%。如果奶牛的粪便培养也呈阳性，屠宰体重和价值分别降低多达15%和31%。对于有肠炎或水肿记录的病例，屠宰体重和价值分别额外降低20%和31%。因此，总结得出体重损失高达31%，屠宰价值损失高达48%。粪便培养阴性的奶牛只有在最后2次检测中ELISA呈阳性时，屠宰结果才会降低。MAP造成的屠宰体重和屠宰价值损失比之前估计的更为严重。这些损失可以通过重复的牛奶ELISA检测来预测，无论是否通过粪便培养进行确认。
