秸秆制粒对肉牛反刍、消化、瘤胃发酵及体增重的影响

本研究测定分析了秸秆制粒饲喂肉牛对其采食、反刍、养分表观消化率、瘤胃发酵和增重的影响,以丰富秸秆饲料化利用方式。试验选取30头18月龄左右、活重接近的西杂肉牛,随机分成3组(每组10头),分别饲喂粉碎玉米秸秆(对照组)、玉米秸秆颗粒饲料(试验Ⅰ组)及玉米秸秆精粗饲料颗粒(试验Ⅱ组)。结果表明,1)秸秆制粒饲喂肉牛,其采食、反刍、咀嚼时间均有所缩短,且每食团咀嚼时间显著少于对照组(P=0.004),而试验Ⅱ组采食时长显著低于对照组(P=0.032)。2)除试验Ⅰ组中性洗涤纤维的表观消化率显著低于对照组外(P0.05),3组肉牛其他养分的表观消化率均无显著差异。3)秸秆粉碎制料后饲喂肉牛影响瘤胃发酵,与对照组比较,试验Ⅰ组瘤胃pH值及丁酸含量显著下降(P0.05),而乙酸含量和乙酸/丙酸显著升高(P0.05);试验Ⅱ组瘤胃液丁酸含量显著下降(P0.05),乙酸/丙酸及NH_3-N含量显著升高(P0.05)。4)秸秆粉碎制粒饲喂肉牛能显著增加日增重和饲料转化率(P0.05),试验Ⅰ组及试验Ⅱ组日增重较对照组分别高出0.36和0.38kg,饲料转化率(料重比)分别提高27.86%和29.09%。

Effects of straw pellets on rumen function and live weight gain of beef cattle

The effects of different corn straw pellets on rumen function,apparent digestibility,rumen fermenta-tion and weight gain of beef cattle were determined to assess the potential for increased use of straw in feed pro-cessing.Thirty 18-month old Simmental cross cattle with similar body weight were randomly divided into a control group and two groups fed straw,groupⅠ and group Ⅱ.Ten animals were allocated to each group.The control and groupⅠ groups were fed crushed corn straw and corn straw pellets at 50% of dietary fibre,respec-tively.Group Ⅱ was fed straw-concentrate pellets providing the same corn fibre intake as the group Ⅰ diet. The results showed that ingestion,rumination and chew time of cattle fed straw pellets were shorter than that those fed crushed straw,and chew time per food ball of cattle fed straw pellets and ingestion time of group Ⅱanimals were significantly lower than the control group (P <0.05).There were no differences in apparent di-gestibility of diets in any group except for NDF (neutral detergent fiber)digestibility in groupⅠ which was sig-nificantly lower than the control group (P <0.05 ).Rumen fermentation differed among the three groups;groupⅠ had lower pH value and butyrate content in rumen gastric juice than the control group (P <0.05),but had higher acetate content and acetate/propionate ratio(P <0.05).There were significantly decreased butyrate content and increased acetate/propionate ratio and NH 3-N content in rumen gastric juice from group Ⅱ than that the control group(P <0.05).Higher daily weight gain and feed conversion rate were observed in groupⅠand group Ⅱ animals(P <0.05);daily weight gain increased by 0.36 kg and 0.38 kg and feed conversion in-creased by 27.9% and 29.1% compared with the control group,respectively.