豆渣混贮对青年期奶牛生长性能、营养物质表观消化率、瘤胃发酵及甲烷排放的影响

Effects of Soybean Residue Mixed Silage on Growth Performance,Nutrient Apparent Digestibility,Rumen Fermentation and Methane Emission of Cows

本试验以豆渣、麦麸和玉米粉为原料,按鲜重基础8∶1∶1的比例进行混合发酵(混合后水分含量65%),获得豆渣混贮,并用该混贮替代青年期奶牛基础饲粮中的豆粕、麦麸和玉米,探究豆渣混贮对奶牛生长性能、营养物质表观消化率、饲养成本、血清生化指标、瘤胃发酵和甲烷(CH_(4))排放的影响。采用单因素随机试验设计,选取体重[(311.0±29.8)kg]相近的青年期荷斯坦奶牛24头,随机分为对照组和豆渣混贮组,每组12头。结果表明:豆渣混贮具有良好的发酵品质,主要表现为低pH和高乳酸含量。与对照组相比,豆渣混贮组干物质(DM)和有机物(OM)采食量没有显著变化(P>0.05),酸性洗涤纤维(ADF)采食量则显著升高(P<0.05),粗蛋白质(CP)采食量有升高的趋势(P=0.06);豆渣混贮组OM和中性洗涤纤维(NDF)表观消化率显著降低(P<0.05),DM表观消化率呈降低趋势(P=0.07);豆渣混贮组的平均日增重(ADG)显著升高(P<0.05),而饲料费用显著降低(P<0.05);豆渣混贮显著提高了血清中总胆固醇(TC)、甘油三酯(TG)、血氨(BA)和补体4(C4)含量(P<0.05);豆渣混贮对CH4排放量及瘤胃主要发酵参数均无显著影响(P>0.05)。综上所述,豆渣混贮对青年期奶牛生长性能、瘤胃发酵和血清生化指标无不利影响,可作为一种较经济的精料资源用于奶牛生产。

In this study,soybean residue(SR),wheat bran and corn flour were used as raw materials for mixed fermentation at a ratio of 8∶1∶1 based on fresh weight(65%moisture content after mixing)to obtain SR mixed silage,which was used to replace soybean meal,wheat bran and corn in the basal diet of young dairy cows.To investigate the effects of SR mixed silage on growth performance,the nutrient apparent digestibility,feeding cost,serum biochemical indexes,rumen fermentation and methane(CH4)emission of cows.The experiment was a randomized complete block design,and 24 Holstein dairy heifers with the similar body weight of(311.0±29.8)kg,were employed and divided into two groups as control group and SR mixed silage group,and each group had 12 cows.Results showed that SR mixed silage exhibited good fermentation quality,as indicated by the low pH and great lactate content.Compared with control group,cows fed SR mixed silage had no influence on the dry matter(DM)and organic matter(OM)intake(P>0.05),while had greater acid detergent fiber(ADF)intake(P<0.05)and a tendency of greater crude protein(CP)intake(P=0.06).Cows fed SR mixed silage had lower apparent nutrient digestibility of OM and neutral detergent fiber(NDF)(P<0.05),and a tendency of lower apparent nutrient digestibility of DM(P=0.07).SR mixed silage group exhibited greater average daily gain(ADG)(P<0.05),and lower feed cost for the whole experiment(P<0.05).SR mixed silage group had greater contents of cholesterol(TC),triglyceride(TG),blood ammonia(BA)and complement 4(C4)in serum(P<0.05).The CH4 emission and the main rumen fermentation parameters were not significantly different in the control group and SR mixed silage group(P>0.05).In conclusion,SR mixed silage has no adverse effects on the growth performance,rumen fermentation and serum biochemical indexes of cows,and can be used as an economical concentrate resource in production of dairy cows.