A systematic review and meta-analysis of prevalence of subclinical mastitis in dairy cows in India.

The purpose of the study was to provide the pooled estimate of the prevalence of subclinical mastitis among dairy cows in India and to examine the consistency of those estimates between published studies. We have conducted a systematic review of prevalence of subclinical mastitis in dairy cows for the period 1995-2014 using electronic and non-electronic databases. Meta-analysis of 28 studies was done under random effects model using Metaprop package in R software. The pooled estimate of prevalence of subclinical mastitis on cow-basis was obtained using 6344 cows from 25 studies and was found to be 46.35 % (95 % CI 39.38; 53.46). Meta-analysis for quarter-wise prevalence of subclinical mastitis was carried out using 18,721 udder quarters of dairy cows from 23 studies, and the pooled estimate of prevalence of subclinical mastitis on quarter-basis was found to be 23.25 % (95 % CI 18.15; 29.27). Meta-analysis showed that there is statistically high heterogeneity for the prevalence estimates between published studies. The present study reported that there is high prevalence of subclinical mastitis in dairy cows in India, which might be responsible for low productivity in lactating cows in India over the years and needs to be controlled by adopting scientific, managemental, and therapeutic measures. Dairy farmers can reduce incidence and economic losses due to subclinical mastitis under the guidance of field veterinarians.