生长期牦牛蛋白质需要量的研究

Study on the Protein Requirement of Growing Yak

将１８头１．５岁生长牦牛分为Ⅰ、Ⅱ、Ⅲ三组，分别饲喂含ＣＰ６．７１％，１０．１４％，１３．４３％的日粮，用比较屠宰试验、消化代谢试验和饲养试验相结合的方法研究其氮代谢。结果表明：Ⅰ、Ⅱ、Ⅲ组日增重分别为５４．０６ｇ，１９３．６７ｇ，２４７．４７ｇ，其中Ⅱ组与Ⅰ组差异显著（Ｐ＜０．０５），Ⅲ组与Ⅰ组差异极显著（Ｐ＜０．０１），而Ⅲ组与Ⅱ组差异不显著（Ｐ＞０．０５）；相应的尿氮（ＵＮ）排出（ｇ／ｄ·Ｗ￣（０．０５２））分别为０．５６２，１．２９１，１．７６２，其中Ⅱ、Ⅲ与Ⅰ差异极显著（Ｐ＜０．０１），Ⅱ与Ⅲ差异显著（Ｐ＜０．０５）；在氮沉积（ＮＲ）、采食氮利用效率方面，三组均无显著差异（Ｐ＞０．０５）。生长牦牛的维持需要量ＲＤＣＰｍ＝６．０９３Ｗ￣（０．５２），增重需要量ＲＤＣＰｇ＝（１．１５４８／△Ｗ＋０．０５０９／Ｗ￣（０．５２））￣（－１）。得出的三个回归方程均呈强直线相关（Ｐ＜０．０１）：１．ＵＮ与进食氮（ＮＩ）的回归方程ＵＮ（ｇ／ｄ）＝－０．１１Ｗ￣（０．５２）＋０．４７３２ＮＩ（ｎ＝９，ｒ＝０．９２８）２．粪氮（ＦＮ）与干物质进食量（ＤＭＩ）及ＮＩ的回归方程ＦＮ（ｇ／ｄ）＝－０．７５１０（１＋０．８?

growing yaks,1. 5 years old, were divided into 3 groups and fed on dietscontaining 6. 71%, 10. 14%,and 13. 43%CP(group Ⅰ、Ⅱand Ⅲ,respectively).comparativeslaughter experiment. digestive and metabolic experiments,and feeding trial were used tostudy their nitrogen metabolism. The results showed that the average daily gains were 54. 06g, 193. 67g ,and 247.47g,respectively,with a significant difference (P<0. 05)between group Fand groupⅠ,and a highly significant difference(P<0.01 ) between group Ⅲ and groupⅠ,but there was no significant difference(P> 0. 05 ) between group Ⅲ andⅡ.correspond-ingly,the urine nitrogen(UN)excreted with highly significant difference(P<0.01)betweengroupsⅡ,Ⅲ and group Ⅰ,a significant difference(P<0.05)between groupⅡand group Ⅲ,was 0.562,1. 29l and 1. 762g/d.W￣(0.52),resp. But there was no significant difference(P>0. 05)in aspects of nitrogen retention(NR) and utilization of nitrogen intake among the 3 groups. The maintenance requirement of CP for growing yak is:and the gain requirement of CP for Rrowing yak is:The three regression equations calculated from the study are showed highly linear corre-lation(P<0. 01):1. The regression between UN and nitrogen intake(NI):UN(g/d)=-0. 122W￣(0.52)+0. 4732NI (n=9,r=0. 928)2.The regression among fecal nitrogon(FN),dry matter intake(DMI)and NI:FN(g/d)=-0.7510(1+0. 87741 gW)W￣(0.52)+0. 6336W￣(0.52)lg(DMI×NI)(n=9,r=0.887)3.The regression between NR and NI:NR(g/d)=-0. 5753W￣(0.52)+0. 4610NI(n=9,r=0. 921)