全株玉米青贮饲粮营养价值改进技术对肉牛生长性能及血清生化指标的影响

Effects of Improvement Techniques of Nutritional Value of Whole Corn Silage Feed on Growth Performance and Serum Biochemical Indices of Beef Cattle

本试验旨在研究全株玉米青贮饲粮营养价值改进技术对肉牛生长性能及血清生化指标的影响。选用60头体重为(220±12)kg的和牛×安格斯F 1阉公牛,按照随机区组试验设计分为4组,每组15头牛,第1组饲喂以全株玉米青贮为主要粗饲料的基础饲粮;第2组饲喂以加入青贮添加剂制作的全株玉米青贮(简称加菌青贮)为主要粗饲料的饲粮,添加量为10 g/t;第3组饲喂在第2组饲粮中添加过瘤胃赖氨酸(RPL)的饲粮,添加量为8.95 g/d;第4组饲喂在第3组饲粮中添加过瘤胃蛋氨酸(RPM)的饲粮,添加量为2.98 g/d。试验包括预试期7 d和正试期90 d。结果表明:1)第3、4组的平均日增重显著高于第1组(P<0.05),各组之间的干物质采食量差异不显著(P>0.05),第1组的料重比极显著高于第2、3和4组(P<0.01),第1、2组显著高于第3、4组(P<0.05)。2)第2组粗蛋白质表观消化率极显著高于第1组(P<0.01),第3、4组显著高于第1组(P<0.05);各组间中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)表观消化率差异不显著(P>0.05);第2、3和4组粗脂肪和无氮浸出物表观消化率分别极显著(P<0.01)和显著高于第1组(P<0.05)。3)各组间血清谷草转氨酶(AST)、谷丙转胺酶(ALT)和氨甲酰磷酸合成酶-Ⅰ(CPS-Ⅰ)活性差异不显著(P>0.05)。4)第3、4组血清尿素氮(UN)和肌酐含量显著低于第2组(P<0.05),第4组血清半胱氨酸含量显著低于第1、2组(P<0.05),但对于其他血清生化指标,各间差异不显著(P>0.05)。5)第3、4组血清生长激素含量显著高于第1组(P<0.05),各组间其他激素指标差异不显著(P>0.05)。综上所述,对于以全株玉米青贮为主要粗饲料的基础饲粮,在加菌基础上单独添加RPL和同时添加RPL和RPM可以提高肉牛的平均日增重,本试验中3种改进技术都可以提高试验牛的饲料转化率,加菌青贮同时添加RPL的效果更明显。

The objective of this experiment was to study the effects of improvement techniques of nutritional value of whole corn silage feed on growth performance and serum biochemical indices of beef cattle.Sixty Japanese Beef×Angus F 1 crossbred steers with an average body weight of(220±12)kg were block into 4 groups with 15 beef in each group.Group 1 were fed a basal diet with whole corn silage as main roughage;group 2 were fed a diet with whole corn silage added silage additives as main roughage,and the supplemental level was 10 g/t;group 3 were fed the group 2 diet added rumen-protected lysine(RPL),and the supplemental level was 8.95 g/d;group 4 were fed the group 3 diet added rumen-protected methionine(RPM),and the supplemental level was 2.98 g/d.The experiment included a pretrial 7 d and a trial 90 d.The results showed as follows:1)the average daily gain in groups 3 and 4 was significantly higher than that in group 1(P<0.05),dry matter intake had no significant difference among groups(P>0.05),the feed/gain in groups 1 was significantly higher than that in groups 2,3 and 4(P<0.05),furethemore,the feed/gain in groups 1,2 was significantly higher than that in groups 3 and 4(P<0.05).2)The apparent digestibility of crude protein in group 2 was significantly greater than that in group 1(P<0.01),while the apparent digestibility of crude protein in groups 3 and 4 was significantly greater than that in group 1(P<0.05),the apparent digestibilities of neutral detergent fiber(NDF)and acidic detergent fiber(ADF)had no significant difference among groups(P>0.05),and the apparent digestibilities of ether extract and nitrogen free extract in groups 2,3 and 4 was significantly greater than that in group 1(P<0.01 or P<0.05),respectively.3)Serum aspertate aminotransferase(AST),alanine amino enzyme(ALT)and carbamyl phosphate synthetase-Ⅰ(CPS-Ⅰ)activities had no significant difference among groups(P>0.05).4)Plasma urea nitrogen and creatinine contents in groups 3 and 4 were significantly lower than those in group 2(P<0.05),serum cysteine content in group 4 was significantly lower than that in groups 1 and 2(P<0.05),however,the other serum biochemical indices had no signicicant difference among groups(P>0.05).5)The content of growth hormone in serum in groups 3 and group 4 was significantly higher than that in group 1(P<0.05),and there was no significant difference in other serum hormone indexes among groups(P>0.05).The results indicate that inoculated whole corn silage diet with the addition of RPL alone or RPL和RPM can increase average daily weight gain of beef cattle,and the three improved techniques in this experimemt can increase feed conversion ratio,and inoculated whole corn silage and adding RPL at the same time has better effect for beef cattle.