Department of Population Medicine, University of Guelph, Guelph, ON, Canada N1G 2W1.
Elanco Animal Health, Greenfield, IN 46140.
J Dairy Sci. 2018 Nov;101(11):10383-10390. doi: 10.3168/jds.2018-14960. Epub 2018 Aug 23.
The objective of this prospective single cohort study was to determine the effect of health status at arrival on growth in milk-fed veal calves. Upon arrival at the veal facility, calves were evaluated using a standardized health scoring system and weighed, and the supplier of the calf was recorded. The calves were followed until slaughter, when the hot carcass weight (HCW) was reported. To calculate average daily gain (ADG), the HCW was transformed into an estimated live weight, weight at arrival was subtracted, and this value was divided by the number of days on feed. A mixed linear regression model was created to evaluate the association of health status on arrival with the ADG throughout the production period. A total of 4,825 calves were evaluated at arrival; however, due to inconsistent HCW data from one slaughter plant, and 357 calves dying during the production period, 2,283 calves were used for analysis. In the final model, 7 variables were significantly associated with ADG. Housing location within the farm, method of calf procurement (drover or auction-derived calves versus direct delivery from local farms) and having a higher body weight at arrival were associated with a higher ADG. The season of arrival (summer or fall compared with winter) and being dehydrated at arrival were associated with a lower ADG. Days on feed was also significant in the multivariable model and had a quadratic relationship with ADG. The associations identified suggest that there may be value in scoring dehydration and body weight at arrival to a veal facility.
本前瞻性单队列研究的目的是确定到达时的健康状况对牛奶喂养小牛肉牛生长的影响。到达小牛肉场时,使用标准化健康评分系统对小牛进行评估并称重,并记录小牛的供应商。对小牛进行跟踪,直到屠宰,报告热胴体重 (HCW)。为计算平均日增重 (ADG),将 HCW 转换为估计的活重,从到达时的体重中减去,然后将该值除以饲养天数。创建混合线性回归模型来评估到达时的健康状况与整个生产期间 ADG 的关联。共有 4825 头小牛在到达时进行了评估;然而,由于一个屠宰场的 HCW 数据不一致,以及 357 头小牛在生产期间死亡,因此只有 2283 头小牛用于分析。在最终模型中,有 7 个变量与 ADG 显著相关。农场内的饲养位置、小牛采购方式(赶牛或拍卖衍生小牛与直接从当地农场交付)以及到达时体重较高与 ADG 较高相关。到达的季节(夏季或秋季与冬季相比)和到达时脱水与 ADG 较低相关。饲养天数在多变量模型中也很重要,与 ADG 呈二次关系。确定的关联表明,对到达小牛肉场时的脱水和体重进行评分可能具有价值。