As part of an integrated study on health and production of dairy cattle on smallholder farms in central
Average milk yield was low (5.8 kg/day; median = 5kg/day) and lactation length was long (20 months). Clinical mastitis risk was low (1% per month). Somatic cell counts (SCC) were high (median = 620 x 103); the previously suggested threshold of 300 000 cells/ml would classify 71% of quarters as positive for subclinical mastitis. Bacteria were commonly isolated, with S. aureus as the most common pathogen isolated (22.1% of all samples). Infections with mastitis pathogens, cow-age and milk yield were associated with increases in SCC. However, S. aureus was the only mastitis pathogen associated with decreased milk yield. Few specific mastitis control measures were applied. The only farm-level variable associated with high SCC was the method of drying off. Gradual drying off decreased SCC.