Kennedy A E, Byrne N, Garcia A B, O'Mahony J, Sayers R G
Animal & Bioscience Research Department, Animal & Grassland Research and Innovation Centre, Teagasc, Moorepark, Fermoy, Co. Cork, Ireland.
Department of Biological Sciences, Cork Institute of Technology, Bishopstown, Co. Cork, Ireland.
BMC Vet Res. 2016 Mar 2;12:43. doi: 10.1186/s12917-016-0667-y.
Infection with Mycobacterium avium subspecies paratuberculosis (MAP) has been associated with reductions in milk production in dairy cows and sub optimal fertility. The aim of this study was to highlight the production losses associated with testing MAP ELISA positive in Irish dairy cows. Secondary objectives included investigation of risk factors associated with testing MAP ELISA positive. A survey of management practices on study farms was also conducted, with examination of associations between management practices and herd MAP status. Blood samples were collected from 4188 breeding animals on 22 farms. Samples were ELISA tested using the ID Screen Paratuberculosis Indirect Screening Test. Production parameters examined included milk yield, milk fat, milk protein, somatic cell count, and calving interval. The association between MAP ELISA status and production data was investigated using multi-level mixed models. Logistic regression was used to identify risk factors for testing JD blood ELISA positive at individual cow level and to identify associations between farm management practices and herd MAP status.
Data were available for 3528 cows. The apparent prevalence recorded was 7.4%. Mixed model analysis revealed no statistically significant association between testing MAP ELISA positive and dairy cow production parameters. Risk factors associated with testing positive included larger sized herds being over twice more likely to test positive than smaller herds (OR 2.4 P = <0.001). Friesians were less likely to test positive relative to other breeds. A number of study farmers were engaged in management practices that have previously been identified as high risk for MAP transmission e.g., 73.1% pooled colostrum and 84.6% of study farmers used the calving area to house sick animals throughout the year. No significant associations however, were identified between farm management practices and herd MAP status.
No production losses were identified; however an apparent prevalence of 7.4% was recorded. With the abolition of EU milk quotas herd size in Ireland is expanding, as herds included in this study were larger than the national average, results may be indicative of future JD levels if no JD control programmes are implemented to minimise transmission.
副结核分枝杆菌（MAP）感染与奶牛产奶量下降及繁殖力欠佳有关。本研究旨在突出爱尔兰奶牛MAP ELISA检测呈阳性所带来的生产损失。次要目标包括调查与MAP ELISA检测呈阳性相关的风险因素。还对研究农场的管理实践进行了调查，研究管理实践与牛群MAP状况之间的关联。从22个农场的4188头繁殖动物采集了血样。使用ID Screen副结核间接筛查试验对样本进行ELISA检测。所检查的生产参数包括产奶量、乳脂、乳蛋白、体细胞计数和产犊间隔。使用多层次混合模型研究MAP ELISA状况与生产数据之间的关联。采用逻辑回归来确定个体奶牛层面JD血ELISA检测呈阳性的风险因素，并确定农场管理实践与牛群MAP状况之间的关联。
有3528头奶牛的数据可用。记录的表观患病率为7.4%。混合模型分析显示，MAP ELISA检测呈阳性与奶牛生产参数之间无统计学显著关联。与检测呈阳性相关的风险因素包括规模较大的牛群检测呈阳性的可能性是规模较小牛群的两倍多（比值比2.4，P = <0.001）。相对于其他品种，弗里生牛检测呈阳性的可能性较小。一些参与研究的农场主采用了先前已被确定为MAP传播高风险的管理实践，例如，73.1%的农场主混合初乳，84.6%的参与研究的农场主全年使用产犊区域来安置患病动物。然而，未发现农场管理实践与牛群MAP状况之间存在显著关联。
未发现生产损失；然而，记录的表观患病率为7.4%。随着欧盟牛奶配额的取消，爱尔兰的牛群规模正在扩大，由于本研究中的牛群规模大于全国平均水平，如果不实施JD控制计划以尽量减少传播，结果可能预示着未来的JD水平。
