Our objective was to evaluate effects of feeding milk replacer (MR) at 2 feeding rates on digestion, intake, and growth of young dairy calves, via a meta-analytical approach using individual data. A database was developed from 10 published studies from the Nurture Research Center (Provimi; Brookville, OH), in which 26 dietary treatments and 491 calves from 0 to 8 wk of age in 13 nursery trials, and 22 dietary treatments and 485 calves from 8 to 16 wk of age in 13 grower trials occurred. Male Holstein calves (n = 491; initial body weight 42.8 ± 4.9 kg) were randomly assigned to 1 of 2 treatments: (1) moderate (MOD), 0.64 to 0.66 kg of dry matter (DM)/d for the first 35 to 39 d, followed by half the allotment per d for 3 to 7 d, fed at the a.m. feeding only; (2) high (HI), 0.92 to 1.07 kg of DM/d for the first 35 to 44 d, followed by half the allotment per d for 5 to 7 d, fed at the a.m. feeding only. Calves were weaned at 6 to 7 wk of age. Milk replacer ranged from 24.8 to 28.6% crude protein (CP) and 17.6 to 20.2% fat; starter ranged from 17.3 to 22.2% CP and 3.0 to 4.3% fat on a DM basis. On d 56 calves (n = 485) moved into pens (4 calves/pen) by treatments and were fed starter (19.4 to 22.3% CP and 3.4 to 4.6% fat, DM basis) blended with 5% hay until d 112. In all nursery trials (d 0 to 56), calves fed MOD had lower average daily gain (ADG; 0.634 vs. 0.545 kg/d), gain/DMI (0.488 vs. 0.466 kg/kg), and hip width change (0.069 vs. 0.064 cm/d), but greater starter intake (0.473 vs. 0.696 kg/d) compared with calves fed HI. Apparent total-tract digestibility of DM (73.3 vs. 78.4%), organic matter (OM; 74.1 vs. 79.0%), CP (74.8 vs. 78.9%), and neutral detergent fiber (NDF; 40.8 vs. 53.9%) were greater for calves fed MOD vs. HI when estimated during wk 8. In all grower trials (d 56 to 112), ADG (1.015 vs. 0.976 kg/d), gain/DMI (0.375 vs. 0.349 kg/kg), and hip width change (0.089 vs. 0.081 cm/d) were greater, but dry feed intake per kg of BW0.75 did not differ (87.8 vs. 88.2 g/d) for calves previously fed MOD vs. HI. Apparent digestibility of DM (78.7 vs. 76.0%), OM (79.8 vs. 77.0%), CP (80.5 vs. 78.4%), and NDF (54.8 vs. 45.8%) were greater for calves fed MOD vs. HI when estimated between wk 11 to 13. Over the entire 112-d period, calves fed MOD had lower ADG (0.805 vs. 0.784 kg/d) but tended to have greater hip width change (8.415 vs. 8.589 cm) compared with calves fed HI. Under the conditions of this study, feeding higher MR rates caused calves to partially lose growth advantage during the weaning transition and further decreased BW gain and structural growth in the grower period (d 56 to 112), which could be due to reductions in nutrient digestibility as a result of feeding more MR.

中文翻译：

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通过荟萃分析方法评估了代乳喂养率对荷斯坦奶牛犊到4个月大的生长性能的影响。

我们的目标是通过荟萃分析方法，使用个体数据，评估以两种饲喂速率饲喂代乳品（MR）对年轻奶牛犊的消化，摄入和生长的影响。从Nurture研究中心（Provimi; Brookville，OH）的10项公开研究中开发了一个数据库，其中13项幼儿园试验中有0至8周龄的26种饮食疗法和491头犊牛，8项试验中有22种饮食疗法和485头犊牛。在13个种植者试验中达到16周龄。将雄性荷斯坦犊牛（n = 491；初始体重42.8±4.9 kg）随机分配至2种处理方法之一：（1）中度（MOD），头35至65天干物质（DM）/ d为0.64至0.66 kg 39天，随后每天分配一半，持续3至7天，仅在上午喂食时喂食；（2）高（HI），前35到44 d为0.92至1.07 kg DM / d，随后每天分配一半，持续5至7天，仅在上午喂食时喂食。小牛在6至7周龄时断奶。代乳品的粗蛋白（CP）为24.8至28.6％，脂肪为17.6至20.2％。DM的首发含量范围为CP的17.3％至22.2％，脂肪的3.0％至4.3％。在第d天，通过处理将56头犊牛（n = 485）移入围栏（4头犊牛/笔），并饲喂与5％干草混合的起始剂（19.4至22.3％CP和3.4至4.6％脂肪，以DM为基准），直到d 112。所有保育试验（0至56天），饲喂MOD的犊牛平均日增重（ADG; 0.634 vs. 0.545 kg / d），增重/ DMI（0.488 vs. 0.466 kg / kg）和臀部宽度变化（0.069 vs. （0.064 cm / d），但与喂入HI的犊牛相比，入门者的进食量更大（0.473 vs. 0.696 kg / d）。DM（73.3 vs. 78.4％），有机物（OM; 74.1 vs. 79.0％），CP（74.8 vs. 78.9％）的表观总消化率 当在第8周进行估算时，MOD和HI饲喂的犊牛的中性洗涤剂纤维和中性洗涤剂纤维（NDF；分别为40.8和53.9％）更大。在所有种植者试验（第56至112天）中，ADG（1.015对0.976 kg / d），增重/ DMI（0.375 vs. 0.349 kg / kg）和臀部宽度变化（0.089 vs. 0.081 cm / d）更大，但每公斤BW0.75的干饲料摄入量没有变化（87.8 vs. 88.2 g / d） ）之前饲喂MOD对HI的小牛。估计MOD和HI饲喂的犊牛的表观消化率（78.7 vs. 76.0％），OM（79.8 vs. 77.0％），CP（80.5 vs. 78.4％）和NDF（54.8 vs. 45.8％）更高。在11周到13周之间。在整个112天期间，与HI犊牛相比，MOD犊牛的ADG较低（0.805 vs. 0.784 kg / d），但臀部宽度变化较大（8.415 vs. 8.589 cm）。在这项研究的条件下，