Prevalence of subclinical mastitis and associated risk factors in smallholder dairy cows in Tanzania
- E. D. Karimuribo, BVM, MVM, PhD1,
- J. L. Fitzpatrick, BVMS, PhD, MRCVS2,
- E. S. Swai, BVM, PhD3,
- C. Bell, BVetMed, PhD, MRCVS4,
- M. J. Bryant, BSc, PhD5,
- N. H. Ogden, BVSc, DPhil, MRCVS6,
- D. M. Kambarage, BVSc, MVM, PhD1 and
- N. P. French, BVSc, MSc, PhD, DLSHTM, MRCVS7
- 1 Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, PO Box 3021, Morogoro, Tanzania
- 2 Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ
- 3 Veterinary Investigation Centre, PO Box 1068, Arusha, Tanzania
- 4 Royal (Dick) School of Veterinary Studies, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG
- 5 Department of Agriculture, School of Policy and Development, University of Reading, White Knights, PO Box 237, Reading RG6 6AR
- 6 Foodborne, Waterborne and Zoonotic Infections Division, Centre for Infectious Disease Prevention and Control, Public Health Agency of Canada, FMV, Université de Montréal, 3200 Sicotte, CP 5000, Saint-Hyacinthe, Québec, J2S 7C6, Canada
- 7 Institute of Veterinary, Animal and Biomedical Sciences, College of Sciences, Massey University, Palmerston North, New Zealand
- Dr Karimuribo's present address is Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ
Abstract
A cross-sectional study was carried out on 200 randomly selected farms in each of the Iringa and Tanga regions of Tanzania to estimate the prevalence and risk factors for subclinical mastitis in dairy cows kept by smallholders. Subclinical mastitis was assessed using the California mastitis test (cmt), and by the bacteriological culture of 1500 milk samples collected from 434 clinically normal cows. The percentages of the cows (and quarters) with subclinical mastitis were 75·9 per cent (46·2 per cent) when assessed by the cmt and 43·8 per cent (24·3 per cent) when assessed by culture. Factors significantly associated with an increased risk of a cmt-positive quarter were Boran breed (odds radio [or]=3·51), a brought-in cow (rather than homebred) (or=2·39), peak milk yield, and age. The stripping method of hand milking was associated with a significantly lower prevalence of cmt-positive quarters (or=0·51). The cmt-positive cows were more likely to be culture positive (or=4·51), as were brought-in (or=2·10) and older cows.
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