ABSTRACT
The study is undertaken in five organised dairy farms located in Chennai, Trichy and Karur districts of Tamil Nadu to assess the incidence of clinical and sub clinical mastitis and predisposing factors such as Herd, Breed, Parity, stage of lactation and the efficiency of two screening tests for the diagnosis of sub clinical mastitis (SCM) in the dairy farms. A total of 159 cows with 636 quarters samples screened for clinical mastitis signs and SCM by modified California mastitis test (mCMT) and somatic cell count (SCC).The results showed that 9.4 per cent of animals had clinical mastitis, 66.7 per cent had SCM by mCMT and 77.4 per cent by SCC. The quarter wise incidence of SCM was 47.6 per cent as screened by mCMT and 51.7 per cent by SCC. There are no significant differences observed in the incidence of clinical mastitis and SCM in farm and breed wise. Parity (p<0.01), Stage of lactation by SCC method (p<0.05), Quarter-wise (p<0.05) incidence have significant differences of occurrence. SCM as screened by mCMT and SCC were compared for agreement by Cohen’s Kappa statistics and the per cent agreement for the two methods of screening SCM was 54.7 per cent with a P-value of 0.000. The study conclude that the higher SCM incidence in organised dairy farms as 66.7 per cent by mCMT and 77.4 per cent by SCC and necessitate the need of effective mastitis control program to be implemented at the farm level