Abstract: By the comparative study on the beef quality of growing Holstein dairy bull,Simmental cattle, Xinjiang Brown calf and Xinjiang local cattle,the assay was aimed to explore the internal beef quality of the dairy bull. Four different breeds of 18 month age cattle were slaughter in the same nutrition model. Carcass were taken back up the right muscle as meat sample. Edible quality,normal composition of nutrition and amino acids were detected and analysed. The results showed that marbling, beef color, water losing rate,water retention capacity and cooking percentage of Holstein dairy bull were better than Xinjiang Brown calf and Xinjiang local cattle, but weaker than Simmental cattle. The tenderness of Holstein dairy bull was better than Xinjiang local cattle. The contents of crude protein and crude ash were 20.14% and 1.11%,there were no significant differences during each breeds (P>0.05). The content of dry matter was 26.30%, it was significantly higher than Xinjiang Brown calf and Xinjiang local cattle (P<0.05), lower than Simmental cattle (P>0.05). The content of crude fat was 10.04%, which was significantly higher than other breeds (P<0.05). Moreover,Holstein dairy bull contained every amino acids which were needed by human body. Among them,the contents of methionine,glutamate,glycine,histidine and taurine were rich, and the proportion of amino acid was also well.

Key words: Holstein dairy bull; meat quality; normal composition of nutrition; amino acid