Johnson-Ifearulundu Y, Kaneene J B, Lloyd J W
College of Veterinary Medicine, Population Medicine Center, Michigan State University, East Lansing 48823, USA.
J Am Vet Med Assoc. 1999 Mar 15;214(6):822-5.
To perform a herd-level analysis of economic losses associated with paratuberculosis in dairy herds.
Cross-sectional study.
A multistage stratified random sample of 121 dairy herds in Michigan.
A 2-part questionnaire was used to gather data on management practices, herd productivity, labor use, and expenditures. Blood samples were collected from a random sample of cows > or = 2 years old in each herd and tested for antibodies to Mycobacterium paratuberculosis. A herd was considered negative for paratuberculosis if results for all cows tested were negative. Multivariable linear regression was used to evaluate the data.
A 10% increase in proportion of cows positive for paratuberculosis was associated with a 33.4 kg (73.5 lb) decrease in mean weight of culled cows. Mortality rate among herds positive for paratuberculosis was 3% higher than rate among herds negative for paratuberculosis. Herds positive for paratuberculosis did not have a significantly higher annual number of hours of labor per cow than did herds negative for paratuberculosis.
For a herd of average size and cull rate, the reduction in mean weight of culled cows attributable to paratuberculosis represented a loss of approximately $1,150 annually for each 10% increase in herd prevalence of paratuberculosis. The increased mortality rate attributable to paratuberculosis represented a loss of between $1,607 and $4,400 on the basis of lost slaughter value and cost of replacement heifers.
对奶牛群中与副结核病相关的经济损失进行群体水平分析。
横断面研究。
密歇根州121个奶牛群的多阶段分层随机样本。
使用两部分问卷收集管理实践、牛群生产力、劳动力使用和支出的数据。从每个牛群中随机抽取年龄≥2岁的奶牛采集血样，检测副结核分枝杆菌抗体。如果所有检测奶牛的结果均为阴性，则该牛群被视为副结核病阴性。使用多变量线性回归评估数据。
副结核病阳性奶牛比例增加10%，与淘汰奶牛平均体重下降33.4千克（73.5磅）相关。副结核病阳性牛群的死亡率比副结核病阴性牛群高3%。副结核病阳性牛群每头奶牛每年的劳动小时数并不显著高于副结核病阴性牛群。
对于平均规模和淘汰率的牛群，副结核病导致的淘汰奶牛平均体重下降，意味着副结核病牛群患病率每增加10%，每年损失约1150美元。基于屠宰价值损失和后备小母牛替换成本，副结核病导致的死亡率增加造成的损失在1607美元至4400美元之间。
