Journal of the South African Veterinary Association, 2009, 80(3): 163–168
A cross sectional study was conducted during October and November 2006 on 69
smallholder dairy farms with lactating cows in Mvomero and Njombe districts Tanzania,
to determine the prevalence of mastitis and to assess the milk quality on the study farms.
Clinical mastitis was investigated using clinical changes of udder and milk at animal level.
Cow-side California Mastitis Test (CMT) and microbiological cultures were used to assess
subclinical mastitis at quarter level. Milk quality was determined on bulk milk samples at
herd level using alcohol and acidity tests, butter fat content, total solids, ash content as well
as Delvotest® for antimicrobial residues. Overall prevalence of clinical mastitis at herd level
in both districts was 21.7 % (n = 69). Based on CMT, prevalence of subclinical mastitis at
animal level was 51.6 %(n = 91). Prevalence of bacterial isolates at animal level was 35.2%
(n = 91) while for fungal it was 16.7 % (n = 90). Based on CMT results, prevalence of
subclinical mastitis at quarter level was 30 % (n = 353), while for bacteria and fungi it was
16%and 6%respectively. Contamination of milk with antimicrobial residues was 4.5%(n=
67). The milk quality parameters for most of the milk samples were within acceptable levels.
Findings in this study have demonstrated high prevalence of subclinical mastitis that may
contribute to low productivity of dairy cattle in both districts. About 20%ofCMTsubclinical
cases had no involvement of microbial pathogens that suggested the need for minimal
interventions with antimicrobial agents. These findings call for use of udder disinfectants
and improved milking hygiene as intervention strategies to control mastitis on the smallholder
dairy farms in Tanzania.