【摘要】 雅江雪牛是以西藏犏牛为母本，安格氏牛为父本进行杂交的一个F2代新品种，仍具有雄性不育的特征。雅江雪牛继承了父本的高生产性能，但其基础代谢研究尚少。通过瘤胃瘘管，全粪全尿法对育肥期1.5 a的雅江雪牛进行代谢研究，结果表现为母雪牛粗蛋白的代谢量为（2.69±0.07）g/w^0.75，公雪牛为（2.21±0.23）g/w^0.75；母雪牛对氨基酸总量的代谢量为2.85 g/w^0.75，公雪牛为2.95 g/w^0.75；对必须氨基酸的需要量，母雪牛为1.03 g/w^0.75，公雪牛为0.99 g/w^0.75；维持代谢ME的需要量，母雪牛为（848.23±30.75）KJ/w^0.75，公雪牛为（729.40±61.39）KJ/w^0.75；母雪牛纤维素中NDF维持量（21.23±0.57）g/w^0.75，公雪牛为（18.59±1.33）g/w^0.75。24 h瘤胃纤维素滤袋中NDF的消化率仅为5.29%，而总消化道中NDF的消化率为79.68%，说明74.39%的NDF是由瘤胃原虫和结肠中微生物进行消化的。试验揭示了雅江雪牛对主要物质的代谢量，也证明了瘤胃原虫对纤维素消化的重要性。更多还原

【Abstract】 The Yajiang crossbred cattle,resulting from the hybridization of Tibetan female Dzo and male Angus,represents a novel cattle breed characterized by male infertility.This breed has inherited the high production performance traits from the male Angus parent,but there has been limited research focused on its basal metabolic rate.In order to address this gap in knowledge,a study was conducted on Yajiang crossbred cattle at the age of 1.5 years,utilizing the methods of total fecal and total urine collection,as well as the use of rumen fistulas for metabolic investigations.The results showed that the maintenance metabolic requirement for crude protein in females was （2.69±0.07） g/w^0.75,whereas in males,it stood at （2.21±0.23） g/w^0.75.The total amino acid requirement was 2.85 g/w^0.75 for females and 2.95 g/w0.75 for males.The maintenance energy （ME） requirements were （848.23±30.75） kJ/w^0.75 for females and （729.40±61.39） k J/w0.75 for males.Additionally,the NDF （Neutral Detergent Fiber） metabolic rates were （21.23±0.57） g/w^0.75 for females and （18.59±1.33） g/w^0.75 for males.Notably,the digestibility of NDF within cellulose filter bags placed in the rumens was a mere 5.29%after a24-hour period.However,upon comprehensive analysis,it was determined that the total digestibility throughout the entire digestive tract amounted to 79.68%.This outcome underscored the significant role played by rumen protozoa and colonic microorganisms,responsible for the digestion of 74.39%of NDF.In summary,this experiment shed light on the metabolic rates of key nutrients in Yajiang crossbred cattle and underscored the vital contribution of rumen protozoon to NDF digestion.更多还原