Tyler J W, Hancock D D, Wilson L, Muller F, Krytenberg D, Bradish S
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, USA.
J Vet Intern Med. 1999 Jan-Feb;13(1):36-9.
The effect of vaccination with a commercially available R-mutant coliform mastitis vaccine on the survival of comingled dairy calves on a farm with endemic salmonellosis was examined. A total of 864 calves were randomly assigned to either vaccine (n = 435) or control (n = 429) groups. Passive transfer status of each calf was determined using refractometer determination of serum total protein concentration. Logistic models were developed to determine the effects of vaccine group and passive transfer status on calf survival to 100 days of age. In a model in which serum protein concentration was treated as a categorical variable, increasing serum total protein concentrations were associated with decreased mortality until these concentrations exceeded 6.0 g/dL. Calves with serum protein concentrations > 6.0 g/dL had increased risk for mortality compared with calves with serum protein concentrations > 5.5 g/dL but < or = 6.0 g/dL. This increased risk for mortality was supported by the results of a logistic model in which serum protein concentration was treated as a continuous variable. The increased risks associated with high serum protein concentration probably reflect the effect of dehydration in calves with occult disease. Neither model demonstrated any significant association between vaccination status and survival to 100 days of age. Based on these results, the routine immunization of calves cannot be recommended as a strategy to prevent mortality on farms with endemic salmonellosis.
研究了使用市售R突变型大肠菌乳腺炎疫苗对患有地方性沙门氏菌病的农场中混合饲养的奶牛犊牛存活情况的影响。总共864头犊牛被随机分为疫苗组（n = 435）或对照组（n = 429）。使用折射仪测定血清总蛋白浓度来确定每头犊牛的被动转移状态。建立逻辑模型以确定疫苗组和被动转移状态对犊牛存活至100日龄的影响。在一个将血清蛋白浓度视为分类变量的模型中，血清总蛋白浓度的增加与死亡率降低相关，直到这些浓度超过6.0 g/dL。与血清蛋白浓度> 5.5 g/dL但≤6.0 g/dL的犊牛相比，血清蛋白浓度> 6.0 g/dL的犊牛死亡风险增加。血清蛋白浓度被视为连续变量的逻辑模型结果支持了这种增加的死亡风险。与高血清蛋白浓度相关的风险增加可能反映了患有隐匿性疾病的犊牛脱水的影响。两个模型均未显示疫苗接种状态与存活至100日龄之间存在任何显著关联。基于这些结果，不建议将犊牛常规免疫作为预防地方性沙门氏菌病农场中犊牛死亡的策略。
