早期断奶和育肥期饲粮NDF水平对湖羊生长性能和消化代谢的影响

[目的]以湖羊公羔为试验对象,探究早期断奶补饲和育肥前、后期饲粮NDF水平对羔羊生长发育和消化性能的持续影响,计算试验因素间的叠加效应,筛选出最佳的组合饲养方式.[方法]选取体重[ (8.26±2.14) kg]、日龄[(20±2) d]接近的健康湖羊公羔120只,随机分为4组,每组6个重复,每重复5只;饲粮NDF水平...

The Effects of Early Weaning and NDF Levels of Finishing Diets on Growth Performance,Nutrient Digestion and Metabolism of Hu Lambs

【Objective】This study was conducted to explore the effects of early weaning and NDF levels of finishing diets on the growth performance, and nutrient digestion and metabolism of Hu sheep lambs, and to filter out the best combination of feeding methods by calculating the superposition effect between the experimental factors. 【Method】One hundred and twenty Hu lambs with similar body weight [(8.26±2.14) kg] and (20±2 ) days of age were randomly divided into four groups with six replicates in each group and five lambs in each replicate. NDF levels of early finishing diets were 33%(low) and 38%(high), NDF levels of late finishing diets were 28% (low) and 38% (high). Treatments included followings: early weaning (EW) + feeding low NDF diet in early and late finishing stage (EW-LL); early weaning + feeding low NDF diet in early finishing stage and high NDF diet in late finishing stage (EW-LH); early weaning + feeding high NDF diet in early and late finishing stage (EW-HH); ewe reared (ER) + feeding high NDF diet in early and late finishing stage (ER-HH). Early weaned lambs gradually transitioned from breastfeeding to feeding milk replacer at the age of 20 days and supplemented with starter feed. The fattening period was from 61 to 180 days of age. The trial lasted 160 days. The body weight and feed intake of lambs were measured at different stages, and digestibility tests were carried out at 2, 4 and 6 months of age.【Result】There was no significant difference in body weight and average daily gain among four groups (P>0.05) except the average daily gain of lambs from 46 to 65 days of age, which was higher in ER group compared with EW group (P<0.05). The dry matter intake of early-weaned lambs from 21 to 65 days old was significantly higher than that of ewe reared lambs (P<0.05), In the early weaned groups, the pellet intake of lambs fed low-NDF diets during the finishing stage were significantly higher than the other two groups at the age of 121-180 days (P<0.05). The nutrient digestibility, energy and nitrogen utilization of early weaned lambs were lower than those in the ER group at 55 to 65 days of age. But it was inverse at fattening period, the dry matter and organic matter digestibility of lambs fed low NDF diet was higher than those fed high NDF diet in finishing stage (P<0.05). EW-LL group had the highest ADG increase scope by superposition effect analysis. The superimposing effect of the two feeding methods of early weaning and low-NDF diet during the early finishing stage was -50.57%.【Conclusion】According to the whole fattening cycle, early weaning and feeding milk replacer could promote the growth performance of lambs. The fattening effect of the low NDF level diet in the early finishing stage was worse than the high NDF level diet. When lambs have the same diet in the late finishing stage, the weight gain of lambs fed with low NDF diet was better than that of lambs fed with high NDF diet in the early finishing stage. By the comprehensive analysis of the growth performance, digestion and metabolism of lambs, the priority of the combination of feed methods was EW-LL>EW-LH=EW-HH>ER-HH. The combination of early weaning + feeding low NDF diet in early and later finishing stage was recommended in this study.