Fordyce, G. and Anderson, A. and McCosker, K. and Williams, P. J. and Holroyd, R. G. and Corbet, N. J. and Sullivan, M. S. (2013) Liveweight prediction from hip height, condition score, fetal age and breed in tropical female cattle. Animal Production Science, 53 (4). pp. 275-282. ISSN 1836-0939
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Article Link(s): http://dx.doi.org/10.1071/an12253
Hip height, body condition, subcutaneous fat, eye muscle area, percentage Bos taurus, fetal age and diet digestibility data were collected at 17 372 assessments on 2181 Brahman and tropical composite (average 28% Brahman) female cattle aged between 0.5 and 7.5 years of age at five sites across Queensland. The study validated the subtraction of previously published estimates of gravid uterine weight to correct liveweight to the non-pregnant status. Hip height and liveweight were linearly related (Brahman: P<0.001, R-2 = 58%; tropical composite P<0.001, R-2 = 67%). Liveweight varied by 12-14% per body condition score (5-point scale) as cows differed from moderate condition (P<0.01). Parallel effects were also found due to subcutaneous rump fat depth and eye muscle area, which were highly correlated with each other and body condition score (r = 0.7-0.8). Liveweight differed from average by 1.65-1.66% per mm of rump fat depth and 0.71-0.76% per cm(2) of eye muscle area (P<0.01). Estimated dry matter digestibility of pasture consumed had no consistent effect in predicting liveweight and was therefore excluded from final models. A method developed to estimate full liveweight of post-weaning age female beef cattle from the other measures taken predicted liveweight to within 10 and 23% of that recorded for 65 and 95% of cases, respectively. For a 95% chance of predicted group average liveweight (body condition score used) being within 5, 4, 3, 2 and 1% of actual group average liveweight required 23, 36, 62, 137 and 521 females, respectively, if precision and accuracy of measurements matches that used in the research. Non-pregnant Bos taurus female cattle were calculated to be 10-40% heavier than Brahmans at the same hip height and body condition, indicating a substantial conformational difference. The liveweight prediction method was applied to a validation population of 83 unrelated groups of cattle weighed in extensive commercial situations on 119 days over 18 months (20 917 assessments). Liveweight prediction in the validation population exceeded average recorded liveweight for weigh groups by an average of 19 kg (similar to 6%) demonstrating the difficulty of achieving accurate and precise animal measurements under extensive commercial grazing conditions.
|Business groups:||Animal Science|
|Additional Information:||Fordyce, Geoffry Anderson, Angela McCosker, Kieren Williams, Paul J. Holroyd, Richard G. Corbet, Nick J. Sullivan, Michael S. Cooperative Centre for Beef Genetic Technologies (Beef CRC) [4.1.3b]; Meat and Livestock Australia [B.NBP.0382] Operational funding was provided by the Cooperative Centre for Beef Genetic Technologies (Beef CRC: Project 4.1.3b) and Meat and Livestock Australia (Project B.NBP.0382). We sincerely thank the inputs of the large group of people involved in research design and management, managing the cattle and collecting the data. Special thanks are due to Dr Heather Burrow (Beef CRC), Tracy Longhurst, Russ Tyler, Peggy Olsson, Debra Corbet, Neil Cooper, Dave Smith, Dr Brian Burns (DAFF: Department of Agriculture, Fisheries & Forestry, Queensland), Warren Sim (CSIRO), David Johnston, Steve Barwick (Animal Genetics and Breeding Unit, Armidale), Professor Michael McGowan (University of Queensland), Tom Newsome, Don Menzies (Outcross) and Dr Sandi Jephcott (Chinchilla Veterinary Clinic). Many other DAFF and CSIRO staff also assisted. Csiro publishing Collingwood|
|Keywords:||beef cattle pregnancy tropics genotypes seasons wet dry|
|Subjects:||Science > Biology > Reproduction|
Animal culture > Cattle
|Deposited On:||27 Nov 2013 06:47|
|Last Modified:||27 Nov 2013 06:47|
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