Department of Animal Science, University of Minnesota, St. Paul 55108.
Animal Welfare Program, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4.
J Dairy Sci. 2017 Nov;100(11):9186-9193. doi: 10.3168/jds.2017-13198. Epub 2017 Sep 13.
Automated calf feeding systems are increasing in use across the United States, yet information regarding health and mortality outcomes of animals in these systems is limited. The objective of this study was to investigate the relationship between farm management practices, housing, and environmental factors with mortality and health treatment rates of preweaned dairy calves housed in groups with automated feeding systems. Farm records were collected for health treatments and mortality on 26 farms in the Upper Midwest of the United States. Relationships between factors of interest and mortality or treatment rate were calculated using a correlation analysis. Overall median annual mortality rate was 2.6 (interquartile range = 3.6; range = 0.24-13.4%), and 57% of farms reported mortality rates below 3%/yr. Farms that disinfected the navels of newborn calves had lower mortality rate (mean = 3.0%; standard error = 0.8; 78% of farms) than farms that did not disinfect (mean = 7.3%; standard error = 1.6; 22% of farms). Farm size (number of cows on site) was negatively associated [correlation coefficient (r) = -0.53], whereas the age range in calf groups was positively associated (r = 0.58) with mortality rate. Average serum total protein concentration tended to be negatively associated with annual mortality rate (r = -0.39; median = 5.4; range = 5.0-6.4 g/dL). Health treatment rate was positively associated with coliform bacterial count in feeder tube milk samples [r = 0.45; mean ± standard deviation (SD) = 6.45 ± 4.50 ln(cfu/mL)] and the age of calves at grouping (r = 0.50; mean ± SD = 5.1 ± 3.6 d). A positive trend was detected for coliform bacterial count of feeder mixing tank milk samples [r = 0.37; mean ± SD = 3.2 ± 6.4 ln(cfu/mL)] and calf age at weaning (r = 0.37, mean ± SD = 57.4 ± 9.6 d). Seasonal patterns indicated that winter was the season of highest treatment rate. Taken together, these results indicate that, although automated feeding systems can achieve mortality rates below the US average, improvements are needed in fundamental calf care practices, such as colostrum management and preventing bacterial contamination of the liquid diet and the calf environment.
自动化牛犊喂养系统在美国的应用日益增多，但有关这些系统中动物健康和死亡率结果的信息有限。本研究的目的是调查农场管理实践、住房和环境因素与群体饲养的未断奶奶牛犊的死亡率和健康治疗率之间的关系，这些牛犊使用自动化喂养系统。美国中西部上 26 个农场的健康治疗和死亡率记录被收集。使用相关分析计算了感兴趣因素与死亡率或治疗率之间的关系。总体中位数年度死亡率为 2.6（四分位距=3.6；范围=0.24-13.4%），57%的农场报告死亡率低于 3%/年。对新生牛犊的肚脐进行消毒的农场死亡率较低（平均值=3.0%；标准误差=0.8%；78%的农场），而不消毒的农场死亡率较高（平均值=7.3%；标准误差=1.6%；22%的农场）。农场规模（现场奶牛数量）呈负相关[相关系数（r）=-0.53]，而牛犊组的年龄范围呈正相关（r=0.58）与死亡率。平均血清总蛋白浓度与年死亡率呈负相关（r=-0.39；中位数=5.4；范围=5.0-6.4 g/dL）。治疗率与进料管牛奶样本中的大肠菌群细菌计数呈正相关[r=0.45；平均值±标准偏差（SD）=6.45±4.50 ln（cfu/mL）]和分组时牛犊的年龄（r=0.50；平均值±SD=5.1±3.6 d）。进料混合罐牛奶样本中大肠菌群细菌计数呈正趋势[r=0.37；平均值±SD=3.2±6.4 ln（cfu/mL）]和断奶时牛犊的年龄（r=0.37，平均值±SD=57.4±9.6 d）。季节模式表明，冬季是治疗率最高的季节。综上所述，这些结果表明，尽管自动化喂养系统可以实现低于美国平均水平的死亡率，但在基本的犊牛护理实践方面仍需改进，例如初乳管理和防止液体饮食和犊牛环境的细菌污染。
