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Spatiosurvival analysis of mortality on smallholder dairy farms in Tanga and Iringa regions of Tanzania

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Abstract

A combination of survival and spatial analyses was applied to a dataset containing cattle mortalities on smallholder dairy farms in two separate regions (Tanga and Iringa) of Tanzania. Cattle mortality data for the year 1998 were collected retrospectively during the period January to April 1999. The objectives of the current study were, firstly, to quantify the hazard of mortality and, secondly, to investigate whether there was a spatial pattern in the variation that was unaccounted for in the hazard of mortality. A Cox regression model with farm as a frailty term was used to quantify the hazard of mortality. Geostatistical techniques were used to explore the first- and second-order spatial distribution of the farm frailty term. A total of 1,790 cattle from 400 randomly sampled smallholder dairy farms were included in the study. The overall mortality incidence rate for the study was 11.8 per 100 animal years (95% CI 10.0–13.8). The hazard of mortality for male cattle was 2.4 (95% CI 1.7–3.4) times higher than that of female cattle. There was evidence of a first-order spatial pattern, i.e., a tendency for farms with higher frailty to aggregate.

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References

  • Chang’a, J.S., Mdegela, R.H., Ryoba, R., Løken, T., and Reksen, O. 2010. Calf health and management in smallholder dairy farms in Tanzania. Tropical Animal Health and Production, 42, 1669–1676

    Article  PubMed  Google Scholar 

  • Gachohi, J.M., Kitala, P.M., Ngumi, P.N., and Skilton, R.A. 2011. Environment and farm factors associated with exposure to Theileria parva infection in cattle under traditional mixed farming system in Mbeere District, Kenya. Tropical Animal Health and Production, 43, 271–277

    Article  PubMed  Google Scholar 

  • Isaaks, E., and Srivastava, R. 1989. An Introduction to Applied Geostatistics, New York: Oxford University Press

    Google Scholar 

  • Klein, J.P. 1992. Semiparametric estimation of random effects using the Cox model based on the EM algorithm. Biometrics, 48, 795–806

    Article  PubMed  CAS  Google Scholar 

  • Olwoch, J.M., Reyers, B., Engelbrecht, F.A., and Erasmus, B.F.N. 2008. Climate change and the tick-borne disease, Theileriosis (East Coast fever) in sub-Saharan Africa. Journal of Arid Environments, 72, 108–120

    Article  Google Scholar 

  • Phiri, B.J., Benschop, J., and French, N.P. 2010. Systematic review of causes and factors associated with morbidity and mortality on smallholder dairy farms in Eastern and Southern Africa. Preventive Veterinary Medicine, 94, 1–8

    Article  PubMed  CAS  Google Scholar 

  • R Development Core Team 2010. R: A Language and Environment for Statistical Computing. Vienna, Austria: R Foundation for Statistical Computing

    Google Scholar 

  • Ribeiro, Jr., P.J., and Diggle, P.J. 2001. geoR: A package for geostatistical analysis. R-News, 1, 14–18

    Google Scholar 

  • Stevenson, M., Nunes, T., Sanchez, J. and Thornton, R. 2010. epiR: Functions for analysing epidemiological data

  • Swai, E.S., Karimuribo, E.D., Kambarage, D.M. and Moshy, W.E. 2009. A longitudinal study on morbidity and mortality in youngstock smallholder dairy cattle with special reference to tick borne infections in Tanga region: Tanzania. Veterinary Parasitology, 160, 34–42

    Article  PubMed  Google Scholar 

  • Therneau, T.M. and Grambsch, P.M. 2001. Modeling Survival Data: Extending the Cox Model. New York: Springer

    Google Scholar 

  • Wudu, T., Kelay, B., Mekonnen, H.M., and Tesfu, K. 2008. Calf morbidity and mortality in smallholder dairy farms in Ada’a Liben district of Oromia, Ethiopia. Tropical Animal Health and Production, 40, 369–376

    Article  PubMed  CAS  Google Scholar 

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Acknowledgments

The authors appreciate the valuable critique and suggestions provided by Dr. Naomi Cogger of EpiCentre, Massey University, New Zealand. Many thanks to participating farmers for their cooperation. The British government through the Department for International Development (DFID/NRRD), Animal Health Research Programme, funded the study that collected the original data. Many thanks to all participating farmers

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Authors and Affiliations

  1. Zambia Institute of Animal Health, P. O. Box 670237, Mazabuka, Zambia

    Bernard J. Phiri

  2. EpiCentre, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag 11–222, Palmerston North, New Zealand

    Bernard J. Phiri, Jackie Benschop, Mark Stevenson & Nigel P. French

  3. Veterinary Investigation Centre, P. O. Box 1068, Arusha, Tanzania

    Emmanuel S. Swai

  4. Department of Veterinary Medicine and Public Health, Sokone University of Agriculture, P. O. Box 3021, Morogoro, Tanzania

    Esron D. Karimuribo

Authors
  1. Bernard J. Phiri
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  2. Jackie Benschop
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  3. Mark Stevenson
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  4. Emmanuel S. Swai
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  5. Esron D. Karimuribo
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  6. Nigel P. French
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Corresponding author

Correspondence to Bernard J. Phiri.

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Phiri, B.J., Benschop, J., Stevenson, M. et al. Spatiosurvival analysis of mortality on smallholder dairy farms in Tanga and Iringa regions of Tanzania. Trop Anim Health Prod 44, 827–834 (2012). https://doi.org/10.1007/s11250-011-9974-2

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  • DOI: https://doi.org/10.1007/s11250-011-9974-2

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