缓释尿素对育肥牦牛生产性能和屠宰性能的影响

Effects of Slow-Release Urea on Production Performance and Slaughter Performance of Fattening Yaks

试验考察了在饲粮中添加缓释尿素对育肥牦牛生产性能、屠宰性能以及血液生化指标的影响。选择健康体重相近[(277.9±10.4)kg]麦洼公牦牛24头,分为3个处理组,分别为对照组:饲喂原场全混合饲粮(代谢能11.03 MJ/kg,CP 10%);0.5%组:添加玉米干酒糟及其可溶物(DDGS)替代部分粗饲料,降低饲粮中粗料水平,并添加0.5%缓释尿素(TMR的代谢能11.35 MJ/kg,CP 12.77%);1.0%组:利用玉米DDGS替代饲粮中的豆粕和菜粕,并添加1.0%缓释尿素(TMR的代谢能11.42 MJ/kg,CP 12.77%)。牦牛预试期10 d,正试期60 d,在第60天晨饲前收集血清进行指标测定。结果表明:①0.5%组平均日增重高于对照组(P<0.05)。②0.5%组和1.0%组的谷丙转氨酶活性高于对照组(P<0.05),1.0%组高于0.5%组(P<0.05);1.0%组的谷草转氨酶活性高于对照组(P<0.05);1.0%组的血氨浓度高于对照组(P<0.05);1.0%组血浆尿素氮浓度高于0.5%组和对照组(P<0.05)。③0.5%组屠宰率和净肉率分别比对照组高1.1和1.4个百分点(P>0.05)。④0.5%组和1.0%组经济效益较对照组分别提高24.03%和29.96%。联合运用1.0%缓释尿素和玉米DDGS可以完全替代育肥牦牛日粮中的豆粕和菜粕并提高养殖经济效益。

This research examined the effects of adding slow-release urea to the diet of fattening yaks on their production performance,slaughter performance,and blood biochemical indexes.Twenty-four healthy male Maiwa yaks with similar body weight[(277.9±10.4)kg]were selected and divided into three treatment groups:the control group:fed with the original total mixed ration from the farm(ME 11.03 MJ/kg,CP 10%);0.5%group:using corn distillers dried grains with solubles(DDGS)to replace part of roughage in the diet,and to decrease the level of roughage,and adding 0.5%slow-release urea(ME 11.35 MJ/kg,CP 12.77%);1.0%group:using corn DDGS to replace soybean meal and rapeseed meal in the diet,and adding 1.0%slow-release urea(ME 11.42 MJ/kg,CP 12.77%).Yaks were given a 10 d adaptation period and then followed by the 60 d formal feeding experiment.On the 60th day,before the morning feeding,serum samples were collected for biochemical indexes determination.The results showed that:①the average daily weight gain of the 0.5%group was higher than that of the control group(P<0.05).②The alanine aminotransferase activity in both the 0.5%and 1.0%groups were higher than those in the control group(P<0.05),and the 1.0%group was higher than the 0.5%group(P<0.05).The aspartate aminotransferase activity in the 1.0%group was higher than that of the control group(P<0.05).The blood ammonia concentration in 1.0%group was higher than that in control group(P<0.05),and the plasma urea nitrogen in 1.0%group was higher than that in 0.5%and control group(P<0.05).③The slaughter rate and net meat rate of the 0.5%group were 1.1 and 1.4 percentage higher than that of the control group respectively.④The economic benefits of the 0.5%and 1.0%group were improved by 24.03%and 29.96%respectively compared to the control group.The combined use of 1.0%slow-release urea and corn DDGS can completely replace soybean meal and rapeseed meal in the ration of fattening yaks and increase economic benefits.