Optimising the carcass merit of Irish beef cattle using genetic and non-genetic information at the animal and herd level
Date of Award
Doctor of Philosophy
Dr Craig Murphy
Prof Roy Sleator
Prof Donagh Berry
Failure of beef carcasses to achieve desirable carcass specifications represent inefficiencies within the supply chain, namely greater carcass processing costs and the inability of the resulting primal cuts to conform to high-value market specifications. Analysis of a representative sample of prime Irish beef cattle conducted in this thesis determined that 59% of cattle fail to achieve the desired carcass specifications of the supply chain at slaughter. The objective of this thesis was to use readily available information to define strategies that could help to reduce this statistic. Firstly, the likelihood of Irish beef carcasses achieving the desired carcass specifications was found to vary by a variety of animal-level risk factors, as did herd-level best linear unbiased estimates (BLUEs) for carcass traits by herd-level factors; these BLUEs, generated from genetic evaluations, represent the contribution of herd environment to carcass performance. The heritability estimated for binary traits representing the achievement of the desired carcass specification ranged from 0.05 to 0.19, with the genetic standard deviation associated with the binary traits ranging from 0.05 to 0.17 units. A subsequent validation exercise proved that selection of cattle using their genetic evaluations for these specification traits increases the proportion of carcasses achieving the desired specifications. Furthermore, it was determined that the response to genetic selection for carcass merit varies by herd-level BLUEs, signifying the potential to use BLUEs to tailor breeding decisions for individual herds; the response to selection in herds with the highest herd BLUEs was 144%, 141% and 89% of that for carcass weight, carcass conformation and carcass fat, respectively, in herds with the lowest BLUEs. Finally, single nucleotide polymorphisms expressing dominance associations with the carcass traits of interest were detected on eight distinct chromosomes, with imprinting associations detected on 17 distinct chromosomes.
Kenny, David, "Optimising the carcass merit of Irish beef cattle using genetic and non-genetic information at the animal and herd level" (2022). Theses [online].
Available at: https://sword.cit.ie/allthe/507
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