Factors associated with calf mortality in tropically adapted beef breeds managed in extensive Australian production systems

Bunter, Kim L., Johnston, David J., Wolcott, Matthew L. and Fordyce, Geoffry (2014) Factors associated with calf mortality in tropically adapted beef breeds managed in extensive Australian production systems. Animal Production Science, 54 25-36. doi:10.1071/AN12421


Author Bunter, Kim L.
Johnston, David J.
Wolcott, Matthew L.
Fordyce, Geoffry
Title Factors associated with calf mortality in tropically adapted beef breeds managed in extensive Australian production systems
Journal name Animal Production Science   Check publisher's open access policy
ISSN 1836-0939
1836-5787
Publication date 2014
Year available 2013
Sub-type Article (original research)
DOI 10.1071/AN12421
Open Access Status
Volume 54
Start page 25
End page 36
Total pages 12
Place of publication Collingwood, VIC 3066 Australia
Publisher C S I R O Publishing
Collection year 2014
Language eng
Formatted abstract
Data from 9296 calves born to 2078 dams over 9 years across five sites were used to investigate factors associated with calf mortality for tropically adapted breeds (Brahman and Tropical Composite) recorded in extensive production systems, using multivariate logistic regression. The average calf mortality pre-weaning was 9.5% of calves born, varying from 1.5% to 41% across all sites and years. In total, 67% of calves that died did so within a week of their birth, with cause of death most frequently recorded as unknown. The major factors significantly (P < 0.05) associated with mortality for potentially large numbers of calves included the specific production environment represented by site-year, low calf birthweight (more so than high birthweight) and horn status at branding. Almost all calf deaths post-branding (assessed from n ≤ 8348 calves) occurred in calves that were dehorned, totalling 2.1% of dehorned calves and 15.9% of all calf deaths recorded. Breed effects on calf mortality were primarily the result of breed differences in calf birthweight and, to a lesser extent, large teat size of cows; however, differences in other breed characteristics could be important. Twin births and calves assisted at birth had a very high risk of mortality, but <1% of calves were twins and few calves were assisted at birth. Conversely, it could not be established how many calves would have benefitted from assistance at birth. Cow age group and outcome from the previous season were also associated with current calf mortality; maiden or young cows (<4 years old) had increased calf losses overall. More mature cows with a previous outcome of calf loss were also more likely to have another calf loss in the subsequent year, and this should be considered for culling decisions. Closer attention to the management of younger cows is warranted to improve calf survival. Journal compilation  
Keyword Bos indicus
Bos taurus
Calf Survival
Crossbred
Dehorning
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Non HERDC
Queensland Alliance for Agriculture and Food Innovation
School of Veterinary Science Publications
 
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Created: Tue, 25 Mar 2014, 07:28:44 EST by Dr Geoffry Fordyce on behalf of Centre for Animal Science