Calvo-Lorenzo M S, Hulbert L E, Fowler A L, Louie A, Gershwin L J, Pinkerton K E, Ballou M A, Klasing K C, Mitloehner F M
Department of Animal Science, Microbiology and Immunology, School of Veterinary Medicine, Center for Health and the Environment, University of California, Davis 95616.
School of Veterinary Medicine, Microbiology and Immunology, School of Veterinary Medicine, Center for Health and the Environment, University of California, Davis 95616.
J Dairy Sci. 2016 Jun;99(6):4678-4692. doi: 10.3168/jds.2016-10888. Epub 2016 Mar 24.
Dairy calves in the western United States are commonly raised individually in wooden hutches with a space allowance of 1.23m(2)/calf. Recent legislative initiatives in California and across the United States were passed regarding concern over space allowance for farm animals. The objective of this study was to determine if rearing male Holstein calves in wooden hutches modified to increase space allowance would influence measures of performance, lying time per day, health, and respiratory immunocompetence. At 4d of age, 60 calves were randomly assigned to 1 of 3housing treatments: (1) conventional housing (CONV; 1.23m(2)/calf), (2) 1.5 × CONV (MOD; 1.85m(2)/calf), or (3) 3 × CONV (MAX; 3.71m(2)/calf). Intakes of milk and solid feed were recorded daily and body weight was measured at 0, 3, 6, 10, and 12 wk of age. For the first 3 wk of the trial, calves were scored daily for fecal consistency, hydration, and hide cleanliness. In addition, calves were scored for respiratory health (i.e., nasal and eye discharge, ear position) until 7 wk of age. The total lying duration per day was recorded using data loggers at 3, 6, and 10 wk of age. Eight clinically healthy calves from each treatment were sensitized with subcutaneous ovalbumin (OVA) and then challenged with aerosolized OVA to assess calf respiratory immunity at 11 wk of age. Bronchoalveolar lavage fluid (BALF) was collected 4d after the OVA challenge and analyzed for leukocyte differentials and OVA-specific IgG, IgG1, IgA, and IgE. Calf average daily gain and body weight were positively associated with space allowance at approximately 3 wk before weaning and throughout postweaning, respectively. A greater space allowance decreased lying time after 46d. Space allowance did not influence fecal consistency, but there was a tendency for MAX calves to take 1d longer to recover from loose feces than MOD calves. The MAX calves had the fewest (%) observations with feces on their body compared with CONV or MOD. At 3 wk of age, peripheral eosinophil concentrations decreased with increased space allowance. However, observations (%) of eye discharge increased with greater space allowance. Among calves challenged with OVA, MOD calves had the least BALF OVA-IgE, and the percent of BALF eosinophils decreased with increased space allowance. Increased space allowance for calves raised in wooden hutches may improve some measures of calf performance, health, and respiratory immunocompetence.
美国西部的奶牛犊通常单独饲养在木制犊栏中，每头犊牛的空间为1.23平方米。最近，加利福尼亚州和美国各地通过了一些立法举措，这些举措是出于对农场动物空间的担忧。本研究的目的是确定将雄性荷斯坦犊牛饲养在经过改造以增加空间的木制犊栏中，是否会影响其生产性能、每日躺卧时间、健康状况和呼吸道免疫能力的指标。在4日龄时，将60头犊牛随机分配到3种饲养处理中的一种：（1）传统饲养（CONV；每头犊牛1.23平方米），（2）1.5倍CONV（MOD；每头犊牛1.85平方米），或（3）3倍CONV（MAX；每头犊牛3.71平方米）。每天记录牛奶和固体饲料的摄入量，并在0、3、6、10和12周龄时测量体重。在试验的前3周，每天对犊牛的粪便稠度、水分含量和皮毛清洁度进行评分。此外，在7周龄之前对犊牛的呼吸道健康状况（即鼻和眼分泌物、耳朵位置）进行评分。在3、6和10周龄时，使用数据记录器记录每天的总躺卧时间。从每种处理中选取8头临床健康的犊牛，皮下注射卵清蛋白（OVA）进行致敏，然后在11周龄时用雾化OVA进行激发，以评估犊牛的呼吸道免疫力。在OVA激发后4天收集支气管肺泡灌洗液（BALF），并分析白细胞分类以及OVA特异性IgG、IgG1、IgA和IgE。犊牛的平均日增重和体重分别在断奶前约3周和整个断奶后与空间呈正相关。更大的空间在46天后减少了躺卧时间。空间并未影响粪便稠度，但MAX组犊牛从稀便中恢复的时间比MOD组犊牛长1天。与CONV组或MOD组相比，MAX组犊牛身上有粪便的观察次数最少（%）。在3周龄时，外周嗜酸性粒细胞浓度随空间增加而降低。然而，眼分泌物的观察次数（%）随空间增加而增加。在接受OVA激发的犊牛中，MOD组犊牛的BALF OVA-IgE最少，BALF嗜酸性粒细胞百分比随空间增加而降低。增加木制犊栏中饲养的犊牛的空间，可能会改善犊牛生产性能、健康状况和呼吸道免疫能力的一些指标。
