Abstract: Milk samples of Xinjiang Brown cattle and Chinese Holstein cattle from Urumqi breeding cattle farm were collected and isolated culture. The effects of subclinical mastitis on different varieties were compared, information of somatic cell counts (SCC) and colony forming units(CFU),SCC and different ages from different varieties were analyzed. The results showed that there was difference on category of pathogenic bacteria and Xinjiang Brown cattle was prior to Chinese Holstein cattle on the infected rate of Staphylococci; the former has a stronger resistance to disease than the latter; there was a extreme1y significant association two varieties between CFU of SCC＜200 thousand /mL and CFU of SCC>500 thousand /mL (P＜0.05),while there was no significant correlation between CFU of 200 thousand /mL500 thousand /mL(P＞0.05),statistical analysis on complete SCC and culture data showed no association between SCC and bacterial isolation and there was other factors; there was the trend of escalation on SCS of Xinjiang Brown cattle and Chinese Holstein cattle and there was significant correlation on SCS of different varieties.

Key words: subclinical mastitis; SCC; CFU