代乳粉蛋白质水平对早期断奶羔羊生长发育和营养物质代谢的影响

摘要：（目的）本文旨在研究代乳粉蛋白质水平对羔羊开食料采食量、生长发育以及营养物质代谢的影响。（方法）将36只陶赛特（♂）×小尾寒羊（♀）杂交F1羔羊随机分为4组，分别饲喂粗蛋白质含量为21、25及29%的三种等能值代乳粉，并设随母羊哺乳的对照组。在羔羊20、40、60、80、90日龄测定体重及体尺，并在50-60日龄、80-90日龄进行两期消化代谢试验。（结果）结果表明：饲喂代乳粉可促进羔羊尽早采食开食料，四组羔羊的开食料采食量差异显著（p＜0.05），采食量随代乳粉蛋白质水平的升高而降低。三个试验组羔羊全期增重分别为14.1、14.6和13.9 kg，分别比对照组（13.1 kg）提高7.6、11.5和6.1%（p＞0.05）。体尺变化趋势与体重相似，以25%粗蛋白质组最优。代乳粉的粗蛋白质水平对羔羊的干物质、有机物、粗脂肪、钙和磷的表观消化率无显著影响（p＞0.05），80-90日龄期间，29%粗蛋白质组的氮沉积率仅为73.5%，显著低于21和25%粗蛋白质组的77.2和77.6%（p＜0.05）。结论：开食料采食量随代乳粉粗蛋白质水平升高而降低，25%粗蛋白质组羔羊的生长性能和营养物质消化代谢率优于其他两组。

Effects of Protein Concentrations of Milk Replacers on Growth Performance and Nutrient Digestion and Metabolism in Early Weaned Lambs

This trial was conducted to study the effects of milk replacers with different protein concentrations on the intake of starter feeds,growth performance and nutriment digestion in early weaned lambs.Thirty six crossbred F1 lambs（Dorset×Thin-tailed Han sheep）were randomLy divided into 4 groups.A group of lambs suckling their ewe＇s milk was used as control,the others were fed with three milk replacers containing 21%,25% or 29% of protein,respectively.The body weight and size were measured on d 20,40,60,80 and 90 after birth.Two digestion trials were undertaken during d 50-60 and 80-90 after birth.The milk replacers promoted the lambs to ingest the starter feeds earlier,and the intake of the starter feeds was decreased（P 0.05）as the protein level of milk replacers increased.The weight gains of lambs receiving three milk replacers containing 21%,25% or 29% protein were 14.1,14.6,13.9 kg,respectively.Compared with control group,the weight gains of the latter groups above were increased by 7.6%,11.5% or 6.1%,respectively（P 0.05）.The tendency of body size changes was the same as body weight gains.The milk replacer containing 25% protein was the best.The crude protein level had no significant effects on the apparent digestibility of dry matter,organic matter,ether extract,calcium or phosphorus（P 0.05）.The nitrogen retention was 73.5% for 29% protein group,which was significantly lower（P 0.05）than that of 21% protein（77.2%）and 25% protein（77.6%）groups during d 80-90.Conclusion：the intake of starter feeds was decreased with the increasing protein levels of the milk replacers.The growth performance and nutriment digestion in the lambs given the milk replacer of 25% protein were better than the others.