Losinger W C, Heinrichs A J
Centers for Epidemiology and Animal Health, USDA, Fort Collins, CO 80521, USA.
J Am Vet Med Assoc. 1996 Nov 15;209(10):1756-9.
To identify risk factors associated with high mortality rates attributable to respiratory tract problems in female calves prior to weaning.
Cross-sectional national survey.
1,685 dairies.
Dairies that had > or = 3 female calves that were born by a herd member or purchased during a 3-month period were classified into operations with high or low mortality rates attributable to respiratory tract problems in female calves prior to weaning. Step-wise logistic regression was used to identify management practices associated with high mortality rates caused by respiratory tract problems.
1,363 of 47,057 (2.9%) calves died of respiratory tract problems during a 3-month period. Management variables associated with high mortality rates caused by respiratory tract problems were housing of > or = 7 calves in a group and rolling herd average for milk production of < or = 9,072 kg. Also, dairies located in the West or Southeast had higher mortality rates.
Dairy operators that house calves in large groups prior to weaning may need to pay close attention to respiratory tract illness in their calves. Herds with high milk production have lower mortality from respiratory tract illness than herds with low milk production. Dairies in the West and Southeast have higher mortality attributable to respiratory tract problems than dairies in other regions of the country.
确定与断奶前雌性犊牛呼吸道问题所致高死亡率相关的风险因素。
全国性横断面调查。
1685个奶牛场。
在3个月期间内，拥有≥3头由 herd member 出生或购买的雌性犊牛的奶牛场，被分类为断奶前雌性犊牛呼吸道问题所致死亡率高或低的养殖场。采用逐步逻辑回归来确定与呼吸道问题导致的高死亡率相关的管理措施。
在3个月期间，47057头犊牛中有1363头（2.9%）死于呼吸道问题。与呼吸道问题导致的高死亡率相关的管理变量包括一组中饲养≥7头犊牛以及滚动牛群平均产奶量≤9072千克。此外，位于西部或东南部的奶牛场死亡率更高。
在断奶前将犊牛成组饲养的奶牛场经营者可能需要密切关注犊牛的呼吸道疾病。高产奶牛群呼吸道疾病的死亡率低于低产奶牛群。该国西部和东南部奶牛场呼吸道问题导致的死亡率高于其他地区的奶牛场。
