Texas AgriLife Research, San Angelo, USA.
J Anim Sci. 2010 Apr;88(4):1492-502. doi: 10.2527/jas.2009-2410. Epub 2009 Dec 4.
Effects of replacing cottonseed hulls with dry redberry juniper leaves on performance and serum NEFA, urea N, and IGF-1 were investigated in Rambouillet lambs (n = 24, initial BW = 28.6 +/- 4.94 kg). In a study with 2 feeding periods (period 1 = 65% concentrate ration, 28 d; period 2 = 85% concentrate ration, 49 d), lambs were individually fed ad libitum treatment diets containing cottonseed hulls (control; CSH), one-half of the cottonseed hulls replaced by dry juniper leaves (CSHJ), or all the cottonseed hulls replaced by dry juniper leaves (JUN). Lamb BW was similar on d 0 and 14, but increasing juniper in the diet linearly reduced (P = 0.04) BW on d 28. Differences in BW during period 1 are attributed to ADG and average daily DMI linearly decreasing (P < 0.001) with increasing concentrations of juniper, with lambs fed CSH, CSHJ, or JUN diets having ADG of 0.34, 0.30, and 0.14 kg, respectively. Differences in average daily DMI are attributed to secondary compounds in the cottonseed hulls and juniper and nutrient-toxin interactions. Lambs fed CSHJ diets had the greatest (P = 0.04) G:F compared with lambs fed CSH and JUN during period 1. Lambs fed JUN diets tended to have the greatest (P = 0.09) NEFA concentrations during period 1, and increasing juniper in the diet linearly reduced (P = 0.006) serum urea N and IGF-1 on d 14 and 28, respectively. During period 2, intake and growth of lambs fed JUN diet rapidly increased, resulting in all lambs having similar ADG, DMI, G:F, and BW. When period 2 began (d 33), serum NEFA and urea N were similar (P > 0.12) among lambs, but serum IGF-1 tended to be linearly reduced (P = 0.09) by increasing juniper in the diet. At times during period 2, lambs fed CSHJ had the greatest (P < 0.02) serum urea N (d 40 and 82) and IGF-1 (d 54) concentrations. Results were interpreted to indicate that air-dried redberry juniper leaves can replace all of the cottonseed hulls in lamb feedlot rations. Feeding 30% juniper in the diet for a longer period of time during the initial feeding period probably would have further reduced growth performance.
本研究旨在探讨用干红山花椒叶替代棉籽壳对绵羊生产性能及血清 NEFA、尿素氮和 IGF-1 的影响。选用初始体重为 28.6±4.94kg 的 24 只罗姆尼羊，进行了为期 2 个饲养阶段的试验（阶段 1：65%浓缩饲料，28d；阶段 2：85%浓缩饲料，49d）。试验采用单因子完全随机设计，将绵羊分为 3 个处理组，分别饲喂棉籽壳（对照组；CSH）、棉籽壳的一半被干红山花椒叶替代（CSHJ）或全部被替代（JUN）的日粮。试验第 0 天和第 14 天绵羊体重没有差异，但随着日粮中红山花椒叶的增加，绵羊体重在第 28 天线性下降（P=0.04）。第 1 阶段的体重差异归因于平均日增重和平均日采食量线性下降（P＜0.001），随着红山花椒叶浓度的增加，分别饲喂 CSH、CSHJ 和 JUN 日粮的绵羊平均日增重分别为 0.34、0.30 和 0.14kg。平均日采食量的差异归因于棉籽壳和红山花椒叶中的次生化合物以及营养-毒素相互作用。第 1 阶段，与饲喂 CSH 和 JUN 日粮的绵羊相比，饲喂 CSHJ 日粮的绵羊的饲料转化效率最高（P=0.04）。第 1 阶段，饲喂 JUN 日粮的绵羊的血清 NEFA 浓度最高（P=0.09），随着日粮中红山花椒叶的增加，绵羊血清尿素氮和 IGF-1 在第 14 天和第 28 天分别呈线性下降（P=0.006）。第 2 阶段，饲喂 JUN 日粮的绵羊快速增加采食量和生长，结果所有绵羊的平均日增重、采食量、饲料转化效率和体重均相似。第 2 阶段开始（第 33 天），绵羊血清 NEFA 和尿素氮之间无显著差异（P＞0.12），但血清 IGF-1 随着日粮中红山花椒叶的增加而线性下降（P=0.09）。在第 2 阶段的某些时间，饲喂 CSHJ 日粮的绵羊的血清尿素氮（第 40 天和 82 天）和 IGF-1（第 54 天）浓度最高（P＜0.02）。结果表明，风干红山花椒叶可以替代绵羊育肥日粮中的全部棉籽壳。在初始饲养阶段，用饲料喂养 30%的红山花椒叶可能会进一步降低生长性能。
