Department of Animal Science, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, I. R. Iran.
Department of Animal Science, College of Agriculture, Isfahan University of Technology, Isfahan 84156-83111, I. R. Iran.
J Dairy Sci. 2018 Aug;101(8):7061-7072. doi: 10.3168/jds.2017-13798. Epub 2018 May 16.
This study evaluated the interactive effects of forage provision on performance, nutritional behavior, apparent digestibility, rumen fermentation, and blood metabolites of dairy calves when corn grains with different fermentability were used. Sixty 3-d-old Holstein calves were randomly assigned to 1 of 4 treatments in a 2 × 2 factorial arrangement. Dietary treatments were (1) steam-flaked (SF) corn without alfalfa hay (AH) supplementation (SF-NO), (2) SF corn with AH supplementation (SF-AH), (3) cracked (CR) corn without AH supplementation (CR-NO), and (4) CR corn with AH supplementation (CR-AH). All calves received the same amount of pasteurized whole milk and weaned on d 56 of the experiment; the study was terminated on d 70. Steam-flaked corn contained higher amounts of gelatinized starch in comparison with cracked corn (44.1 vs. 12.5% of total starch, respectively). Starter intake was not affected by corn processing methods or AH provision during the pre- or postweaning periods. However, we noted an interaction between corn processing methods and forage supplementation for starter intake during d 31 to 50 of the experiment, where calves fed on SF-AH starter had greater starter intake than those fed SF-NO starter, but the starter intake was not different between CR-NO and CR-AH fed calves. Furthermore, AH increased average daily gain (ADG) of calves fed an SF-based diet but not in calves fed a CR-based diet during the preweaning and overall periods. Interaction between forage provision and time was significant for ADG and feed efficiency, as calves supplemented with forage had higher ADG (0.982 vs. 0.592, respectively) and feed efficiency compared with forage unsupplemented calves at the weaning week. Forage supplementation resulted in more stable ruminal condition compared with nonforage-fed calves, as evidenced by higher ruminal pH (5.71 vs. 5.29, respectively) at postweaning and lower non-nutritive oral behavior around weaning time (55 vs. 70.5 min, respectively). The concentration of blood β-hydroxybutyrate was also greater in calves supplemented with forage than in unsupplemented calves. Results of the present study indicated that performance response and skeletal growth were the same between 2 corn processing methods. Forage provision improved ADG of calves fed the SF-based diet, but not the CR-based diet throughout the study.
本研究评估了在使用不同发酵性玉米谷物时，提供草料对奶牛犊牛的性能、营养行为、表观消化率、瘤胃发酵和血液代谢物的互作影响。60 头 3 日龄荷斯坦奶牛犊随机分配到 4 种处理的 2×2 析因设计中。日粮处理为：（1）无苜蓿干草（AH）添加的蒸汽压片（SF）玉米（SF-NO），（2）有 AH 添加的 SF 玉米（SF-AH），（3）无 AH 添加的破碎玉米（CR）（CR-NO），和（4）有 AH 添加的 CR（CR-AH）。所有犊牛接受相同量的巴氏消毒全牛奶，并在实验的第 56 天断奶；研究于第 70 天结束。与破碎玉米相比，蒸汽压片玉米含有更高比例的糊化淀粉（分别为 44.1%和 12.5%的总淀粉）。在断奶前和断奶后，玉米加工方式或 AH 供应均不影响犊牛的开食料采食量。然而，在试验的第 31 至 50 天期间，我们观察到玉米加工方式和草料补充对开食料采食量的互作，饲喂 SF-AH 开食料的犊牛比饲喂 SF-NO 开食料的犊牛采食量更大，但 CR-NO 和 CR-AH 组之间的开食料采食量没有差异。此外，在断奶前和整个阶段，AH 增加了基于 SF 的日粮喂养犊牛的平均日增重（ADG），但对基于 CR 的日粮喂养犊牛的 ADG 没有影响。在 ADG 和饲料效率方面，草料补充与时间之间存在显著的互作，与未补充草料的犊牛相比，补充草料的犊牛在断奶周时 ADG 更高（0.982 对 0.592），饲料效率更高。与未饲喂草料的犊牛相比，补充草料的犊牛瘤胃条件更稳定，表现为断奶后瘤胃 pH 值更高（分别为 5.71 和 5.29），断奶时非营养性口腔行为更少（分别为 55 对 70.5 分钟）。血液β-羟丁酸的浓度在补充草料的犊牛中也高于未补充草料的犊牛。本研究结果表明，两种玉米加工方式对犊牛的性能和骨骼生长影响相同。在整个研究期间，提供草料提高了基于 SF 的日粮喂养犊牛的 ADG，但对基于 CR 的日粮喂养犊牛没有影响。
