Nurture Research Center, Provimi North America, Cargill Animal Nutrition, Brookville, OH 45309.
Nurture Research Center, Provimi North America, Cargill Animal Nutrition, Brookville, OH 45309.
J Dairy Sci. 2021 Jul;104(7):7738-7748. doi: 10.3168/jds.2020-19951. Epub 2021 Apr 15.
The objective of this study was to evaluate 3 milk replacer (MR) feeding programs on calf performance to 4 mo of age. Male Holstein calves (n = 48; 2-3 d old) were randomly assigned to either a moderate rate of MR (MOD; 0.66 kg/d for 39 d, then 0.33 kg/d for 3 d), an ad libitum rate of MR (ADLIB; offered twice daily between 0630 and 0830 h and between 1430 and 1630 h for 35 d, 0.66 kg/d for 4 d, and 0.33 kg/d for 3 d), or a step-up rate of MR (STEPUP; increased from 0.32 to 0.62 kg/d in first 12 d, 0.66 kg/d for 27 d, and 0.33 kg/d for 3 d). The MR (25% CP, 18% fat) was fed twice daily to d 39 and once daily thereafter. During the nursery phase (0-56 d), calves were housed in individual pens and offered textured starter (40% starch, 21% CP on a DM basis) and water ad libitum. Calf body weight (BW) was measured initially and weekly thereafter. Hip widths (HW) were measured initially and every 2 wk thereafter. In the grower phase, (57-112 d), calves were grouped by previous treatment and moved to group pens (4 calves/pen). The same starter used in the nursery phase was blended with 5% chopped grass hay and offered ad libitum. Calf BW and HW were measured on d 56, 84, and 112. Total MR intake per calf averaged 27, 51, and 25 kg for MOD, ADLIB, and STEPUP programs, respectively, with a range of 42 to 63 kg for ADLIB. In the nursery phase, starter intake and feed efficiency were less for ADLIB versus MOD, whereas fecal scores and abnormal fecal score days were greater for calves fed ADLIB versus MOD. Calves fed STEPUP had lesser average daily gain than calves fed MOD. During the grower phase, initial BW was greater for ADLIB versus MOD, though final BW was not different between MOD and ADLIB or STEPUP. Calves previously fed MOD had greater average daily gain, feed efficiency, and HW change than calves fed ADLIB. In this study, feed efficiency was lower when MR was fed ad libitum, and growth advantages observed at 2 mo were lost by 4 mo of age.
本研究旨在评估 3 种代乳粉（MR）喂养方案对 4 月龄以下犊牛的生长性能。雄性荷斯坦犊牛（n = 48；2-3 日龄）随机分为中等 MR 喂养组（MOD；39 日龄时每天 0.66kg，3 日后每天 0.33kg）、自由 MR 喂养组（ADLIB；0630-0830h 和 1430-1630h 之间每天两次提供，35 日龄时每天 0.66kg，4 日后每天 0.33kg）或逐步增加 MR 喂养组（STEPUP；前 12 日每天增加 0.32-0.62kg，27 日龄时每天 0.66kg，3 日后每天 0.33kg）。MR（25%CP、18%脂肪）在 39 日龄前每天提供 2 次，之后每天提供 1 次。在育雏期（0-56 日龄），犊牛单独饲养，提供颗粒型开食料（干物质基础上 40%淀粉，21%CP）和自由饮水。初始时测量犊牛体重（BW），之后每周测量一次。初始时和之后每 2 周测量一次髋宽（HW）。在生长育肥期（57-112 日龄），按照之前的处理方法分组并转移到群体饲养栏（每栏 4 头犊牛）。与育雏期相同的开食料与 5%切碎的干草混合，自由采食。56、84 和 112 日龄时测量犊牛 BW 和 HW。MOD、ADLIB 和 STEPUP 组的平均每头犊牛 MR 摄入量分别为 27、51 和 25kg，ADLIB 组的范围为 42-63kg。在育雏期，ADLIB 组的开食料摄入量和饲料效率低于 MOD 组，而 ADLIB 组的粪便评分和异常粪便评分天数高于 MOD 组。与 MOD 组相比，STEPUP 组的犊牛平均日增重较低。在生长育肥期，ADLIB 组的初始 BW 高于 MOD 组，但 MOD 组和 ABLIB 组或 STEPUP 组的最终 BW 无差异。与 ADLIB 组相比，之前饲喂 MOD 组的犊牛的平均日增重、饲料效率和 HW 变化更大。在这项研究中，当 MR 自由采食时，饲料效率降低，2 月龄时观察到的生长优势在 4 月龄时丧失。
