Prevalence of subclinical mastitis and associated risk factors in lactating cattle in selected sub counties of Kakumiro District, Uganda

Abstract

The development of the dairy industry in Uganda has been slowed down by many factors among which are diseases. Mastitis remains a frequent and economically important disease of dairy cattle (Kakooza et al., 2023). Subclinical mastitis (SCM) poses significant challenges in dairy farming due to its asymptomatic nature, leading to economic losses and food insecurity (Muhwezi et al., 2025). Uganda's Kakumiro District, where dairy farming contributes significantly to household income and food security (UBOS, 2021), the prevalence and associated risk factors of SCM remain poorly characterized. This study was therefore carried out to determine the prevalence of Subclinical mastitis, determine the quarter-level prevalence and identify the associated risk factors. This cross-sectional study, conducted in April 2025 across three sub counties (Bwanswa, Nkooko, and Kasambya) of Kakumiro District, employed the California Mastitis Test (CMT) to investigate SCM prevalence and associated risk factors in 167 lactating cows from 18 purposively selected smallholder farms. Cows were screened for SCM and those with one or more udder quarters score of ≥ 1 (scale 0, T, 1, 2 and 3) were noted as positive. Structured questionnaires and observational checklists were used to collect data on potential risk factors including breed, parity, lactation stage, teat condition, udder hygiene, and milk production levels. The study revealed a high cow-level SCM prevalence of 61.7% (103/167), Quarter level analysis showed the left hind quarter was most frequently affected with quarter prevalence of 37.1%. Risk factor analysis demonstrated significant associations (p<0.05) between SCM and: breed (crossbreeds: 68.93% prevalence; OR=22.968 vs. local breeds), late lactation stage (47.57% prevalence), teat injuries (55.34% prevalence), high milk production (>5L/day: 77.67% prevalence). This research provides the first snapshot assessment of SCM in Kakumiro District, filling a critical knowledge gap in Uganda's dairy disease surveillance. The findings support evidence-based interventions to enhance productivity in smallholder systems, contributing to food security and rural economic development. Future studies should investigate seasonal variations and cost-benefit analyses of control measures.