Fluharty F L, McClure K E
Department of Animal Sciences, Ohio Agricultural Research and Development Center, Wooster, USA.
J Anim Sci. 1997 Mar;75(3):604-10. doi: 10.2527/1997.753604x.
Eighty-eight early-weaned Hampshire x Targhee crossbred lambs (initial BW 23 +/- 3.9 kg) were used in a 2 x 2 factorial design experiment to determine the effects of DM and CP intake on lamb performance and weight and accretion rates of visceral organs during two periods of growth, divided at 36 kg live weight. There were 10 lambs per replicate and two replicate pens per treatment. Dry matter intake was 100 or 85% of ad libitum, and protein intake was 100 (normal) or 125% (high) of the calculated NRC (1985) requirement. Over both periods, lambs allowed ad libitum access to feed had greater (P < .05) ADG, rumen/reticulum, large intestine, and liver weights and faster accretion rates than lambs fed at 85% of ad libitum; however, there were no differences (P = .87) in feed efficiency. For the total trial, lambs fed high protein had greater (P < .01) DMI, ADG, liver and kidney weight and accretion rates, and increased (P < .01) feed efficiency during period 1 compared with lambs fed normal protein concentrations. Diets containing high concentrations of dietary protein resulted in greater DMI and ADG throughout the feeding period compared with diets formulated at NRC (1985) recommended concentrations, indicating that NRC (1985) protein recommendations may limit lamb performance. Restricted feeding resulted in reduced visceral organ mass compared with offering feed for ad libitum consumption. Restricted feeding increased efficiency of feed utilization for gain, in part, through reductions in visceral organ mass.
88只早期断奶的汉普夏×塔吉杂交羔羊（初始体重23±3.9千克）用于一项2×2析因设计实验，以确定干物质（DM）和粗蛋白（CP）摄入量对羔羊生长性能以及两个生长阶段（以36千克活重划分）内脏器官重量和生长率的影响。每个重复组有10只羔羊，每个处理有两个重复栏。干物质摄入量为随意采食的100%或85%，蛋白质摄入量为计算得出的NRC（1985）需求量的100%（正常）或125%（高）。在两个阶段中，随意采食的羔羊比采食随意采食量85%的羔羊具有更高（P<0.05）的平均日增重（ADG）、瘤胃/网胃、大肠和肝脏重量以及更快的生长率；然而，饲料效率没有差异（P = 0.87）。在整个试验中，与采食正常蛋白质浓度的羔羊相比，采食高蛋白的羔羊在第1阶段具有更高（P<0.01）的干物质采食量（DMI）、ADG、肝脏和肾脏重量及生长率，并且饲料效率提高（P<0.01）。与按照NRC（1985）推荐浓度配制的日粮相比，含有高浓度日粮蛋白质的日粮在整个饲喂期内导致更高的DMI和ADG，这表明NRC（1985）的蛋白质推荐量可能会限制羔羊的生长性能。与随意采食相比，限饲导致内脏器官质量降低。限饲部分通过降低内脏器官质量提高了饲料转化为增重的效率。
