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 Jun;104(6):6768-6778. doi: 10.3168/jds.2020-19908. Epub 2021 Mar 25.
This study evaluated effects of milk replacer (MR) feeding rate and fat concentration in MR on total-tract digestion (TTD) and growth performance in Jersey calves. Jersey heifer calves (n = 100, 2 blocks of 50; initially 30 ± 3.0 kg of body weight; 4-11 d of age) were randomly assigned to 1 of 4 treatments in a 2 × 2 factorial arrangement of MR feeding rate [454 g for 42 d, and 227 g for 7 d (MOD); or 454 g for 7 d, 681 g for 35 d, and 341 g for 7 d (HI), as-fed basis] and MR fat content (17 or 24% fat as-fed basis). Milk replacers (24% crude protein as-fed basis) were reconstituted to 14% solids and fed in 2 equal feedings for 42 d, and then mornings only for 7 d. Textured calf starter (21% crude protein, 40% starch, dry matter basis) and water were offered for ad libitum consumption. From d 57 to 112, calf starter was mixed with 5% chopped grass hay. Calves were housed individually to d 56 and housed in groups (4-5 calves/pen) from d 57 to 112. Estimates of TTD were measured in 5 calves/treatment (block 1) at wk 3 of the study using acid-insoluble ash as an indigestible marker. From 0 to 56 d, calf starter intake (CSI) was greater for MOD vs. HI and 17 versus 24% fat; average daily gain was greater for HI versus MOD; and hip width change was greater for 17 versus 24% fat. Estimates of organic matter TTD were greater for HI versus MOD, but neutral detergent fiber TTD was greater for MOD versus HI and for 17 versus 24% fat. From 57 to 112 d, hip height change was greater for MOD versus HI, and hip width change was greater for 17 versus 24% fat. In this study, feeding Jersey calves more MR improved preweaning average daily gain, but had a negative effect on CSI and likely rumen development, as neutral detergent fiber TTD was reduced at 3 wk and frame growth was reduced from d 57 to 112. This resulted in similar final calf body weights between MR feeding rates at the end of the study. No benefits were observed for feeding more fat in MR as CSI or for NDF digestibility, and frame growth was reduced.
本研究评估了代乳粉（MR）喂养率和 MR 中的脂肪浓度对泽西牛犊全肠道消化（TTD）和生长性能的影响。选择 100 头荷斯坦小母牛（n = 100，2 个 50 头的块；初始体重 30 ± 3.0 公斤；4-11 日龄），按 2×2 因子设计，随机分配到 4 种处理之一：MR 喂养率[454 g 持续 42 天，7 天 227 g（MOD）；或 454 g 持续 7 天，681 g 持续 35 天，341 g 持续 7 天（HI），干物质基础]和 MR 脂肪含量（17%或 24%脂肪，干物质基础）。代乳粉（24%粗蛋白，干物质基础）的蛋白质含量为 14%，分为 2 等份喂养 42 天，然后在第 7 天只喂养上午。纹理状小牛开食料（21%粗蛋白，40%淀粉，干物质基础）和水可自由采食。从第 57 天到 112 天，小牛开食料中添加 5%切碎的干草。小牛在第 56 天之前单独饲养，从第 57 天到 112 天在群中饲养（4-5 头/栏）。在研究的第 3 周，通过使用酸不溶灰分作为不可消化标记物，对每个处理组的 5 头小牛（第 1 块）进行 TTD 估计。0-56 天，MOD 组比 HI 组和 17%脂肪组的小牛开食料摄入量（CSI）更高；HI 组的平均日增重更高；17%脂肪组的髋宽变化更大。HI 组的有机物 TTD 估计值大于 MOD 组，但 MOD 组的中性洗涤纤维 TTD 大于 HI 组和 17%脂肪组。57-112 天，MOD 组的髋高变化大于 HI 组，17%脂肪组的髋宽变化大于 HI 组。在这项研究中，给泽西牛犊喂更多的代乳粉提高了断奶前的平均日增重，但对 CSI 和可能的瘤胃发育有负面影响，因为 3 周时中性洗涤纤维 TTD 减少，57-112 天的体型生长减少。因此，研究结束时，两种代乳粉喂养率的最终犊牛体重相似。喂更多的脂肪并没有提高 CSI 或 NDF 消化率的好处，反而会减少体型生长。
