Journal article

Risk factors for post-weaning mortality of Merino sheep in south-eastern Australia

AJD Campbell, AL Vizard, JWA Larsen



OBJECTIVE: To measure associations between body weight, growth rate, sex, time of shearing and post-weaning mortality of Merino sheep. DESIGN: Uni- and multivariable survival analyses of sheep mortality during the first year after weaning, using records (n = 3657) from two field experiments conducted in Western Victoria from 1996 to 2003. RESULTS: Overall mortality was 14.3% (range 4.5-26.8%) and mean maximum mortality rate was 29 deaths/1000 weaners/month. Increased mortality risk was associated with decreases in fleece-free body weight and mean weaner growth rate, particularly at low weights and growth rates. Weaners in the lightest weaning weight quintile had a hazard ratio of 3.5, compar..

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Funding Acknowledgements

We thank the Vizard Foundation, the Australian Sheep Industry Cooperative Research Centre, and the Universities Federation for Animal Welfare for helping to fund this project. The assistance of the staff of Roxby Park and Maurice and Jill Glover is gratefully acknowledged, as is the help of Ms Linda Hygate in acquiring data, and the dedicated technical assistance provided by Ms Dianne Rees. AJDC is in receipt of funding by the Australian Wool Education Trust.