Clinical and subclinical mastitis in smallholder dairy farms in Tanzania: Risk, intervention and knowledge transfer E.D. Karimuribo a, * , J.L. Fitzpatrick b , C.E. Bell c , E.S. Swai d , D.M. Kambarage a , N.H. Ogden e , M.J. Bryant f , N.P. French g a Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, P.O. Box 3021, Morogoro, Tanzania b Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, near Edinburgh, EH26 OPZ, UK c Instiute of Comparative Medicine, University of Glasgow Veterinary School, Bearsden Road, Glasgow, UK d Veterinary Investigation Centre, P.O. Box 1068, Arusha, Tanzania e Groupe de recherche en e ´pide ´miologie des zoonoses et sante ´ publique, Universite ´ de Montre ´al, Canada f Department of Agriculture, University of Reading, UK g Epicentre, Institute of Veterinary, Animal and Biomedical Sciences, College of Sciences, Massey University, Palmerston North, New Zealand Abstract In a cross-sectional study of 400 randomly selected smallholder dairy farms in the Tanga and Iringa regions of Tanzania, 14.2% (95% confidence interval (CI) = 11.6–17.3) of cows had developed clinical mastitis during the previous year. The point prevalence of subclinical mastitis, defined as a quarter positive by the California Mastitis Test (CMT) or by bacteriological culture, was 46.2% (95% CI = 43.6–48.8) and 24.3% (95% CI = 22.2–26.6), respectively. In a longitudinal disease study in Iringa, the incidence of clinical mastitis was 31.7 cases per 100 cow-years. A randomised intervention trial indicated that intramammary antibiotics significantly reduced the proportion of bacteriologically positive quarters in the short-term (14 days post-infusion) but teat dipping had no detectable effect on bacteriological infection and CMT positive quarters. Other risk and protective factors were identified from both the cross-sectional and longitudinal included animals with Boran breeding (odds ratio (OR) = 3.40, 95% CI = 1.00–11.57, P < 0.05 for clinical mastitis, and OR = 3.51, 95% CI = 1.29– 9.55, P < 0.01 for a CMT positive quarter), while the practice of residual calf suckling was protective www.elsevier.com/locate/prevetmed Preventive Veterinary Medicine 74 (2006) 84–98 * Corresponding author. Fax: +255 23 260 4647. E-mail addresses: karimuribo@suanet.ac.tz, ekarimu@yahoo.co.uk (E.D. Karimuribo). 0167-5877/$ – see front matter # 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.prevetmed.2006.01.009