Higher weaning weight improves postweaning growth and survival in young Merino sheep
S. Hatcher A E , J. Eppleston B , R. P. Graham C , J. McDonald D , S. Schlunke D , B. Watt B and K. J. Thornberry AA NSW Department of Primary Industries, Orange Agricultural Institute, Forest Road, Orange, NSW 2800, Australia.
B Central Tablelands Rural Lands Protection Board, PO Box 20, Bathurst, NSW 2795, Australia.
C NSW Department of Primary Industries, PO Box 20, Yass, NSW 2582, Australia.
D Yass Rural Lands Protection Board, PO Box 10, Yass, NSW 2582, Australia.
E Corresponding author. Email: sue.hatcher@dpi.nsw.gov.au
Australian Journal of Experimental Agriculture 48(7) 966-973 https://doi.org/10.1071/EA07407
Submitted: 10 December 2007 Accepted: 13 March 2008 Published: 20 June 2008
Abstract
Two monitoring projects were conducted to investigate weaner mortality in commercial Merino flocks in the Yass and the Central Tablelands Rural Lands Protection Boards located in the Southern Tablelands agricultural region of New South Wales. The projects were conducted in Yass in 2005 and in the Central Tablelands in 2006. A random sample of weaners from four flocks in the Yass board and 11 flocks in the Central Tablelands board were regularly weighed, growth rates were calculated after weaning and survival was determined by the continuing presence of an individual weaner at subsequent weighing activities. Weaning weight was the most important factor in determining postweaning liveweight, growth rates and survival with the significant impact of weaning weight on liveweight persisting for up to 6 months after weaning. Despite the lightest weaners being capable of considerable compensatory growth given sufficient postweaning nutrition, the lightest 25% of weaners were more than twice as likely to die as heavier weaners. A focus on ewe nutrition and parasite control during late pregnancy and lactation will allow Merino producers to achieve higher weaning weights that will set their weaners up for strong postweaning growth with a decreased likelihood of mortality.
Acknowledgements
We wish to acknowledge the support and enthusiasm of the owner/managers of the commercial properties involved in the both the Yass and Central Tablelands RLPBs. Without their cooperation, enthusiasm and support this project would not have been possible. Other RLPB staff, NSW Department of Primary Industries support staff and University of Sydney Veterinary interns provided additional technical assistance as required during the scheduled monitoring activities on each property. The Central Tablelands monitoring project was sponsored by Pfizer’s Eryvac vaccine and received some financial support from Lifetime Wool project, a national project supported by Australian Wool Innovation Ltd, Department of Primary Industries Victoria, Department of Agriculture and Food Western Australia, NSW Department of Primary Industries, Tasmanian Department of Primary Industries and Water, South Australian Research and Development Institute, CSIRO, Austral Park: Coleraine, Billandri Poll Merino Stud, Kendenup and over 120 wool producers across southern Australia.
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