Animal Nutrition Group, Wageningen University and Research, 6700 AH, Wageningen, the Netherlands.
Animal Nutrition Group, Wageningen University and Research, 6700 AH, Wageningen, the Netherlands.
J Dairy Sci. 2017 Oct;100(10):8087-8101. doi: 10.3168/jds.2016-12390. Epub 2017 Aug 17.
High interindividual variation in growth performance is commonly observed in veal calf production and appears to depend on milk replacer (MR) composition. Our first objective was to examine whether variation in growth performance in healthy veal calves can be predicted from early life characterization of these calves. Our second objective was to determine whether these predictions differ between calves that are fed a high- or low-lactose MR in later life. A total of 180 male Holstein-Friesian calves arrived at the facilities at 17 ± 3.4 d of age, and blood samples were collected before the first feeding. Subsequently, calves were characterized in the following 9 wk (period 1) using targeted challenges related to traits within each of 5 categories: feeding motivation, digestion, postabsorptive metabolism, behavior and stress, and immunology. In period 2 (wk 10-26), 130 calves were equally divided over 2 MR treatments: a control MR that contained lactose as the only carbohydrate source and a low-lactose MR in which 51% of the lactose was isocalorically replaced by glucose, fructose, and glycerol (2:1:2 ratio). Relations between early life characteristics and growth performance in later life were assessed in 117 clinically healthy calves. Average daily gain (ADG) in period 2 tended to be greater for control calves (1,292 ± 111 g/d) than for calves receiving the low-lactose MR (1,267 ± 103 g/d). Observations in period 1 were clustered per category using principal component analysis, and the resulting principal components were used to predict performance in period 2 using multiple regression procedures. Variation in observations in period 1 predicted 17% of variation in ADG in period 2. However, this was mainly related to variation in solid feed refusals. When ADG was adjusted to equal solid feed intake, only 7% of the variation in standardized ADG in period 2, in fact reflecting feed efficiency, could be explained by early life measurements. This indicates that >90% of the variation in feed efficiency in later life could not be explained by early life characterization of the calves. It is speculated that variation in health status explains a substantial portion of variation in feed efficiency in later life. Significant relations between fasting plasma glucose concentrations, fecal pH, drinking speed, and plasma natural antibodies in early life (i.e., not exposed to the lactose replacer) and feed efficiency in later life depended on MR composition. These measurements are therefore potential tools for screening calves in early life on their ability to cope with MR varying in lactose content.
犊牛生产中普遍存在个体间生长性能差异较大的现象，这似乎取决于代乳料（MR）的组成。我们的第一个目标是研究健康犊牛的生长性能差异是否可以通过对这些犊牛早期生活的特征来预测。我们的第二个目标是确定在后期喂养高乳糖或低乳糖 MR 的情况下，这些预测是否存在差异。总共 180 头荷斯坦-弗里生公牛犊于 17 ± 3.4 日龄到达设施，在第一次喂食前采集了血液样本。随后，在接下来的 9 周（第 1 期）中，通过与 5 个类别中的每个类别相关的靶向挑战来对犊牛进行特征描述：进食动机、消化、吸收后代谢、行为和应激、和免疫学。在第 2 期（第 10-26 周），130 头犊牛平均分为 2 种 MR 处理：含有乳糖作为唯一碳水化合物来源的对照 MR 和低乳糖 MR，其中 51%的乳糖被葡萄糖、果糖和甘油（2:1:2 比例）等热量替代。在 117 头临床健康的犊牛中，评估了早期生活特征与后期生活生长性能之间的关系。第 2 期的平均日增重（ADG）对照组犊牛（1292 ± 111g/d）比接受低乳糖 MR 的犊牛（1267 ± 103g/d）偏高。使用主成分分析对第 1 期的观察结果进行聚类，然后使用多元回归程序使用主要成分来预测第 2 期的表现。第 1 期的观察结果变化可以预测第 2 期 ADG 的 17%。然而，这主要与固体饲料拒食的变化有关。当 ADG 调整为等于固体饲料摄入量时，第 2 期标准化 ADG 的变化只有 7%，实际上反映了饲料效率，可以通过早期生活测量来解释。这表明，后期生活饲料效率的变化有 >90%无法用犊牛早期生活特征来解释。据推测，健康状况的差异解释了后期生活中饲料效率变化的很大一部分。早期生活（即未接触乳糖代乳料）中空腹血糖浓度、粪便 pH 值、饮水速度和血浆天然抗体与后期生活中的饲料效率之间存在显著关系，这取决于 MR 组成。因此，这些测量值是早期生活中筛选能够应对 MR 中乳糖含量变化的犊牛的潜在工具。
