Wilms J N, Hendriks S, Sugino T, Ghaffari M H, Steele M A, Sauerwein H, Martín-Tereso J, Leal L N
Trouw Nutrition Research and Development, P.O. Box 299, 3800 AG, Amersfoort, the Netherlands; Department of Animal Bioscience, University of Guelph, Guelph, ON, Canada.
Trouw Nutrition Research and Development, P.O. Box 299, 3800 AG, Amersfoort, the Netherlands; Adaptation Physiology, Wageningen University, P.O. Box 338, 6700 AH, Wageningen, the Netherlands.
J Dairy Sci. 2025 May 9. doi: 10.3168/jds.2025-26331.
Fat composition of milk replacer (MR) for calves differs from that of bovine milk fat, resulting in lower levels of butyric (C4:0) and caproic acid (C6:0). These fatty acids play a critical role in the gastrointestinal and metabolic development of calves by supporting rumen epithelial growth, enhancing energy metabolism, and promoting overall gut health. The objective of this study was to evaluate the effects of inclusion of a spray-dried fat concentrate containing tributyrin (TB) and tricaproin (TC) in a high-fat MR on growth, feed intake, and metabolic profiles of ad libitum-fed calves. Forty-eight newborn Holstein calves were blocked based on arrival sequence. Within each block of 2 calves, calves were randomly assigned to a control MR (CON, n = 24) including vegetable fats from palm, coconut, and linseed fats, or to an experimental MR including the same fat blend, to which TB and TC (TRI, n = 24) was added to the same levels found in milk fat. Both MR contained 23.7% crude protein, 27.7% fat, and 35.6% lactose (DM basis) and were fed at 13.5% solids. Calves were group housed and fed ad libitum MR with automated feeders. Weaning was gradual and induced between wk 7-10, after which calves were only fed solid feeds. Starter feed, chopped straw, and water were offered ad libitum throughout the whole study period. Calves were weighed and blood was collected once weekly at 1300h. Calves fed TRI showed a ∼50% reduction in therapeutic intervention days compared with CON. In addition, calves fed TRI consumed significantly more MR and starter feed, resulting in a greater growth. Serum NEFA and plasma total cholesterol were lower, whereas the enzymatic activity of serum ALP was higher in calves fed TRI than in CON. In addition, calves fed TRI had lower serum ghrelin and higher insulin-like growth factor-I concentrations. Incorporating TB and TC is a suitable strategy to increase solid feed intake upon weaning, resulting in better growth performance in ad libitum systems, and to improve health of dairy rearing calves.
犊牛代乳粉（MR）的脂肪组成与牛乳脂肪不同，导致丁酸（C4:0）和己酸（C6:0）水平较低。这些脂肪酸通过支持瘤胃上皮生长、增强能量代谢和促进整体肠道健康，在犊牛的胃肠道和代谢发育中发挥关键作用。本研究的目的是评估在高脂MR中添加含甘油三丁酸酯（TB）和甘油三己酸酯（TC）的喷雾干燥脂肪浓缩物对自由采食犊牛生长、采食量和代谢谱的影响。48头新生荷斯坦犊牛根据到达顺序进行分组。在每组2头犊牛的每个组内，犊牛被随机分配到对照MR（CON，n = 24）组，该组代乳粉包含来自棕榈、椰子和亚麻籽的植物脂肪，或分配到实验MR组，该组代乳粉包含相同的脂肪混合物，并添加了与乳脂中相同水平的TB和TC（TRI，n = 24）。两种MR均含有23.7%的粗蛋白、27.7%的脂肪和35.6%的乳糖（以干物质计），并以13.5%的固形物含量进行饲喂。犊牛成组饲养，通过自动喂料器自由采食MR。断奶是渐进的，在第7至10周诱导断奶，之后犊牛只饲喂固体饲料。在整个研究期间，自由提供开食料、切碎的稻草和水。每周13:00对犊牛称重并采集血液。与CON组相比，饲喂TRI组的犊牛治疗干预天数减少了约50%。此外，饲喂TRI组的犊牛消耗的MR和开食料显著更多，从而实现了更大的生长。饲喂TRI组犊牛的血清非酯化脂肪酸（NEFA）和血浆总胆固醇较低，而血清碱性磷酸酶（ALP）的酶活性高于CON组。此外，饲喂TRI组的犊牛血清胃泌素水平较低，胰岛素样生长因子-I浓度较高。添加TB和TC是一种合适的策略，可增加断奶时的固体饲料采食量，在自由采食系统中实现更好的生长性能，并改善奶牛养殖犊牛的健康状况。
