高精料舍饲条件下不同能量水平对生长期牦牛生长及血液生化指标的影响

Effect of different energy levels on growth performance and blood biochemical indexes of feedlot yaks during growing period

试验旨在探究高精料舍饲下不同能量水平日粮对生长期牦牛生产性能及血液生化指标的影响。选取生长期健康阉牦牛18头,随机分为3个处理组,每组6个重复,进行全舍饲试验,预试期40 d,正式试验期210 d。结果表明:中能量组和高能量组牦牛的平均日增重均显著高于低能量组(P<0.05),高能量组牦牛平均日增重与饲喂时间呈显著的线性关系,中能量组平均日增重与饲喂时间呈显著的二次函数关系。试验的多数时间点,低能量组牦牛血糖低于高能量组或中能量组,甘油三酯高于高能量组和中能量组;短期饲喂高能量日粮,牦牛血液胆固醇含量最低,长期饲喂则相反;随着饲喂时间的延长,血液中转氨酶活性呈降低趋势。研究表明,高精料日粮舍饲能有效应对牦牛冷季掉膘的问题,但对牦牛的肝脏健康有一定的不利影响,随着饲喂时间的延长,这一影响逐渐消失;饲料中添加油脂能促进机体脂肪代谢,但长时间饲喂高油脂饲料会加重肝脏负担。因此,高油脂日粮饲喂时,应把握好饲喂时间。结合平均日增重、健康及成本等综合考虑,采用中能量组饲料饲喂不超过169 d,获得的经济效益最高。

The study was to investigate the effect of diets with different energy levels on the growth performance and blood biochemical indexes of yaks under the condition of full feeding. Eighteen healthy steining yaks during the growing period were selected and randomly divided into three treatment groups with six replicates in each treatment group. The pre-feeding period was 40 d, and the formal feeding period was 210 d. The results showed that the average daily gains of middle energy group and high energy group was significantly higher than that of low energy group(P<0.05). There was a significant linear relationship between daily gain and feeding time in high energy group, and a significant quadratic function relationship between daily gain and feeding time in middle energy group. In most time points of the experiment,the blood glucose of low energy group was lower than that of high energy group or middle energy group, and the triglyceride was higher than that of high energy group and middle energy group. the blood cholesterol content of yak fed with high energy diet for a short time was the lowest, but it was the opposite for a long time. With the extension of feeding time, the transaminase activity in blood fluid decreased. The results indicates that high concentrate diet can effectively deal with the problem of yak fat loss in cold season, but it has a certain adverse effect on the liver health of yak,and the effect gradually disappears with the extension of feeding time. Adding oil in the feed can improve the fat metabolism, but feeding high fat diet for a long time will increase the burden on the liver. Therefore, when the yaks are fed with high fat diets, feeding time should be controlled reasonably. Combined with the comprehensive consideration of daily gain, health and cost, and feeding the middle energy diets for no more than 169 d can obtain the highest economic benefits.