A number of environmental and contagious factors have been associated with subclinical mastitis (SCM), which is a common and costly problem for smallholder dairy farmers (SDF). We conducted a cross-sectional study on 118 cows in their first two months post-calving on 109 SDF in Kenya. The study objective was to investigate the relationships among various cow and farm management parameters and SCM specific to SDF. The stall floor comfort level was assessed through knee impact and wetness tests, and cleanliness on the leg and udder were also scored. Various mastitis prevention measures were also assessed (e.g., milking protocols, and use of teat dip and dry cow therapy). Individual quarter SCM was assessed on each cow using California Mastitis Test (CMT). Univariable and multivariable logistic regression models were fit to determine management factors associated with cow-level SCM. Farm-level, cow-level and quarter-level prevalence of SCM was 45.9% (50/109), 43.2% (51/118) and 21.9 % (103/471), respectively. The proportion of stalls scored as dirty was 33.1% while 49.1% of cows had dirty legs. Only 10.1% of farms were using either disinfectant teat dip or dry cow therapy (or both) to prevent mastitis. Low parity and poor stall hygiene were significantly associated with occurrence of SCM. At high daily milk yield, the probability of having SCM was higher in cows housed in a shed with a dirty versus clean alleyway, with no significant difference at low daily milk yield. From the study findings, we concluded that certain cow characteristics and comfort measures were associated with SCM and need to be incorporated in education plans for farmers in SDF.
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