摘要
The objective of this study was to investigate the effects of a milk byproduct–based starter pellet, high in lactose, on feed intakes, growth, and rumen development when calves were fed either a high or low level of milk. This was done by using a 2 × 2 factorial design, with 120 Holstein heifer calves randomly assigned to 1 of 2 milk treatments and 1 of 2 feed treatments upon enrollment at birth. Calves were either assigned to a low (LM) or high (HM) level of milk replacer by an automated milk-feeding system for individually-housed calves. The LM treatment calves were offered 6 L/d (150 g/L; 1.2 L, 5×/d), whereas HM treatment calves were offered 15 L/d (150 g/L; 3 L, 5×/d) of milk replacer. Calves were also assigned to a milk byproduct- (whey) based starter feed treatment (WF), or a grain-based starter ration (95% concentrate starter pellet, 5% chopped wheat straw) feed treatment (GF). All calves were offered their treatment feed starting on d 5, with water offered ad libitum from d 0. The WF treatment calves were offered 150 g/d of the milk byproduct–based pellet until they consumed the entirety for 2 out of 3 consecutive days. At this point, WF treatment calves received 150 g of the milk byproduct–based pellet top dressed onto the grain-based ration to allow for ad libitum feed consumption until weaned, when they only received the grain-based ration postweaning (d 64–77). Calves on the GF feed treatment received only the grain-based ration. All calves were gradually weaned from d 43 to 63. By design, calves on the HM treatment consumed greater levels of milk than LM treatment calves for the majority of the days in the preweaning phase (8.9 ± 0.11 vs. 5.5 ± 0.11 L/d; SE). Calves on the GF and WF treatments consumed similar amounts of milk in the preweaning phase (7.2 ± 0.11 vs. 7.2 ± 0.11 L/d); however, there was a milk and feed treatment interaction detected for milk consumption in the weaning phase, with HM-GF calves drinking more milk than the other treatments and HM-WF calves drinking more milk than both LM-GF and LM-WF calves. The WF treatment calves had greater solid feed intake during the preweaning phase than GF treatment calves, with no feed intake differences in the weaning or postweaning phases. The WF calves drank more water in the preweaning phase than GF calves. Average daily gain was similar throughout the study between the GF and WF treatment calves. Rumen physiological measures were all similar by the end of the trial (d 77) regardless of feed or milk treatment, suggesting similar rumen development postweaning. Overall, regardless of the level of milk fed, offering the milk byproduct–based starter pellet may increase preweaning feed intake, along with water consumption. However, both feed and milk treatments had similar performance and rumen development measures by the end of the trial.
摘要译文
本研究的目的是探讨牛奶副产品的起动颗粒，高乳糖的影响，当时饲喂高或低水平的牛奶时饲料摄入量，生长和瘤胃发育。这是通过使用2×2因子设计来完成的，120只霍尔斯坦小母牛随机分配到2个牛奶治疗中的1只，在出生时注册后的2种饲料治疗。由自动牛奶馈送系统分配给低（LM）或高（HM）的牛奶替代品，用于单独容纳的小牛。提供6 L / D（150克/升; 1.2L，5×D）提供LM处理犊牛，而HM处理小牛则提供15升（150克/升; 3升，5×/ d）牛奶更换剂。还分配给牛奶副产品 - （乳清）的起始进料处理（WF），或基于谷物的起始饲料（95％浓缩起动颗粒，5％切碎的小麦秸秆）进料处理（GF）。所有犊牛在D 5开始时提供了它们的治疗饲料，水提供了来自D 0的AD Libitum。WF处理小牛在连续3天中消耗了整个牛奶副产品的颗粒，直到它们为直到连续3天消耗2 。此时，WF处理犊牛接收了150g牛奶副产品的颗粒上衣，敷在基于谷物的比例上，以允许AD Libitum饲料消耗直至断奶，当时它们仅接受了基于谷物的出口后切换（D 64-77 ）。 GF饲料处理上的犊牛只接受了基于谷物的比例。所有小牛逐渐从D 43到63断奶。通过设计，HM处理的小腿在预级阶段的大多数日内消耗了比LM处理犊牛更大水平的牛奶（8.9±0.11与5.5±0.11 L / D. ; se）。 GF和WF治疗上的犊牛在普制阶段消耗了相似量的牛奶（7.2±0.11对7.2±0.11L / d）;然而，检测到断奶阶段牛奶消耗的牛奶和饲料治疗相互作用，牛奶牛犊比其他治疗和HM-WF犊牛饮用更多的牛奶，而不是LM-GF和LM-WF犊牛。在普制的阶段，WF治疗犊牛比GF治疗犊牛在普化阶段具有更大的固体进料进料，不会在断奶或切换阶段进行进料进口差异。 WF犊牛在普制阶段喝得多于GF小牛的水。在GF和WF处理小牛之间的研究中，平均每日收益相似。无论饲料或牛奶治疗如何，试验结束时，瘤胃生理措施都是相似的，表明发生了类似的瘤胃发育。总体而言，无论喂养的牛奶水平如何，提供基于牛奶副产品的起始颗粒可能会增加预制性进料进口，以及耗水。然而，在审判结束时，饲料和牛奶治疗均具有类似的性能和瘤胃发展措施。
S.D. Parsons[1];M.A. Steele[1];K.E. Leslie[2];D.L. Renaud[2];C.N. Reedman[2];C.B. Winder[2];T.J. DeVries[1]. Effect of a milk byproduct–based calf starter feed on dairy calf nutrient consumption, rumen development, and performance when fed different milk levels[J]. Journal of Dairy Science, 2022,105(1): 281-300