低蛋白精料补充料对泌乳期放牧牦牛体增重、血清生化指标及乳成分的影响

Effects of Low Protein Concentrate Supplementation on Body Weight Gain,Serum Biochemical Indexes and Milk Composition of Lactating Grazing Yaks

试验旨在研究低蛋白精料补充料补充两种主要过瘤胃氨基酸对泌乳期放牧牦牛体增重、血清生化指标及乳成分的影响。选取健康状况良好、体重相近的24头泌乳牦牛作为试验动物,随机分为3组,每组8个重复。高蛋白组(HP组)饲喂粗蛋白水平为16.66%的精料补充料,中蛋白组(MP组)饲喂粗蛋白水平为15.05%的精料补充料并额外添加0.23%过瘤胃赖氨酸和0.03%过瘤胃蛋氨酸、低蛋白组(LP组)饲喂粗蛋白水平为13.57%的精料补充料并额外添加0.46%过瘤胃赖氨酸和0.07%过瘤胃蛋氨酸。预试期8 d,正试期40 d。结果表明:3组母牦牛终末体重及净增重指标无显著差异(P>0.05);LP组血清中葡萄糖的含量显著低于其他两组(P<0.05),HP组血清尿素氮的含量显著高于LP组(P<0.05),各组间血清其他指标差异均不显著(P>0.05);3组泌乳期牦牛产奶量无显著差异(P>0.05),LP组乳脂率显著高于MP组和HP组(P<0.05),HP组总固形物含量显著低于MP组和LP组(P<0.05)。综上得出,降低泌乳期牦牛精料补充料的粗蛋白水平并补充相应的过瘤胃氨基酸不影响泌乳期牦牛的生产性能,且在降低饲料中豆粕用量的同时能改善机体蛋白质的利用情况,提高了饲粮的氮利用率。

The aim of this experiment was to study the effects of low protein concentrate supplementation and supplementation with two major per rumen amino acids on body weight gain,serum biochemical in-dexes and milk composition of lactating grazing yaks.Twenty-four lactating yaks with good health condi-tion and similar body weight were selected as test animals and randomly divided into three groups with eight replicates in each group.The high protein group(LP group)was fed concentrate supplement with a crude protein level of 16.66%,the medium pro-tein group(MP group)was fed concentrate supple-ment with a crude protein level of 15.05%and an additional 0.23%per rumen lysine and 0.03%per rumen methionine,and the low protein group(LP group)was fed a concentrate supplement with a crude protein level of 13.57%and additional 0.46%per rumen lysine and 0.07%per rumen methionine.The pretest period was 8 days and the formal trial was 40 days.The results showed that there was no significant difference between the final body weight and net weight gain indexes of the three groups of female yaks(P>0.05)and the weight gain of the LP group was higher than that of the other two groups;the content of glucose in serum of the LP group was significantly lower than that of the other two groups(P<0.05),and the content of serum urea nitrogen of the HP group was significantly higher than that of the LP group(P<0.05),and there was no significant difference in other serum indicators among the groups(P>0.05)there was no significant difference in milk yield among the three groups of lactating yaks(P>0.05),the milk fat rate of the LP group was signifi-cantly higher than that of the MP group than that of the HP group(P<0.05)and the total solids of the HP group was significantly lower than that of the MP group and the LP group(P<0.05).In conclusion,lower-ing the crude protein level of concentrate supplements and supplementing the corresponding per rumen amino acids did not affect the production performance of lactating yaks,and it improved the utilization of body protein and nitrogen utilization of the ration while lowering the dosage of soybean meal in the feed.