Prevalence and Determinants of Subclinical Mastitis in dairy Cows under Small-scale farms in Dar es Salaam, Tanzania

Bovine mastitis particularly the subclinical form, poses a significant global challenge to the dairy industry affecting milk yield and quality with high economic losses. A cross-sectional study was conducted between February and May 2023 to determine the prevalence and determinants of subclinical mastitis (SCM) in dairy cows under smallholder dairy farms in Dar es Salaam. A structured questionnaire was administered to 192 households, and 381 cows screened for subclinical mastitis by California Mastitis Test (CMT). Five percent of 1,524 examined teats were blind, the prevalence of SCM was 70.8% at farm, 75.6% at herd and 66.8% at quarter levels. The SCM occurrence based on number of affected quarters per animal was statistically significance (P=0.0001) with 54.17% and 29.86% of cows had four and three-quarters respectively. Friesian and crossbreeds’ cows were more likely to be SCM positive compared (p = 0.0031) to Ayrshire breed. The late-lactation stage and mid-lactation stage were found to be risk factors for SCM. Moreover, farmers' awareness about mastitis, culling mastitic cow, and use of teat lubricants during milking were found to be protective factors. This study found a high prevalence of SCM which might cause economic losses and health public health implication to milk consumers. Thus, suggests on that raising farmers’ awareness about mastitis, use of teat lubricants, and monitoring older and middle-aged cows are the major factors that should be put into consideration for targeted interventions on reducing SCM in dairy cows in small-scale dairy farms in Dar es Salaam.