author(s)
Arun Mourya, PC Shukla, DK Gupta, RK Sharma, Anju Nayak, Brejesh Singh, Anand Jain and Shashi Pradhan

abstract
Subclinical mastitis is defined as inflammation of udder without any visible changes in the udder and milk. In this study, a total of 412 lactating cows were screened by california mastitis test (MCMT), somatic cell count and milk pH. The overall prevalence of infected animal was found to be 31.55 percent on animal basis and 20.18 percent on quarter basis. The age wise prevalence was found to be highest in 5-7 years of age group (38.50%). The highest prevalence of SCM was observed in 4^th parity (44.12%), in early lactation stage (56.25%) and in cross bred (35.06%) animals. Prevalence in organized and unorganized dairy farms is 29.82% and 41.66% respectively. Apparently healthy cattle had a mean value of SCC 1.97 ± 3.11 X 105 cells/ml. The mean SCC in SCM (11.80 ± 4.18 X 10⁵ cells/ml) was significantly (p≤ 0.05) increased as compared to control. Apparently healthy cattle had a mean value of milk pH 6.20 ± 0.08 and in SCM cow milk pH was 6.68 ± 0.09.