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Genomic selection for pork quality and carcass traits in both cross- and pure-bred populations Open Access


Other title
Performance traits
Genetic parameters
Genomic selection
Carcass traits
Genetic correlation
Pork quality traits
Type of item
Degree grantor
University of Alberta
Author or creator
Miar, Younes
Supervisor and department
Wang, Zhiquan (Agricultural, Food, and Nutritional Science)
Examining committee member and department
Ernst, Catherine (Michigan State university; external examiner)
Bruce, Heather (Agricultural, Food, and Nutritional Science)
Korver, Doug (Agricultural, Food, and Nutritional Science; examination chair)
Dixon, Walter (Agricultural, Food, and Nutritional Science; examiner external to the supervisory committee)
Plastow, Graham (Agricultural, Food, and Nutritional Science)
Department of Agricultural, Food, and Nutritional Science
Animal Science
Date accepted
Graduation date
Doctor of Philosophy
Degree level
Pork quality and carcass characteristics are now being integrated into swine breeding objectives because of their economic value. Understanding the genetic basis for these traits is necessary for this to be accomplished. The main objective of this study was to improve pork quality traits in two Canadian swine populations. Data from 6,408 commercial crossbred pigs with performance traits recorded in production systems with 2,100 of them having meat quality and carcass measurements. These pigs were progeny from 139 Duroc boars bred to 429 F1 hybrid Landrace × Large White sows. In the first study, phenotypic and genetic parameters for meat quality and carcass traits were estimated. Heritability estimates (± SE) for carcass traits were moderate to high and ranged from 0.22 ± 0.08 for longissimus dorsi muscle area to 0.63 ± 0.04 for trimmed ham weight, except for firmness that was low. Heritability estimates (± SE) for meat quality traits varied from 0.10 ± 0.04 to 0.39 ± 0.06, for the Minolta b* of ham quadriceps femoris muscle and shear force, respectively. There were high negative genetic correlations between drip loss with pH and shear force and a positive correlation with cooking loss. Genetic correlation between carcass weight with carcass marbling was highly positive. It was concluded that selection for increasing primal and subprimal cut weights with better pork quality may be possible. Furthermore, the use of pH is confirmed as an indicator for pork water-holding capacity and cooking loss. In the second study, heritability, phenotypic, and genetic correlations between performance traits (n=9) with meat quality (n=25) and carcass (n=19) traits were estimated. Performance traits had low-to-moderate heritabilities (±SE), ranged from 0.07±0.13 to 0.45±0.07 for weaning weight, and ultrasound backfat depth, respectively. The results indicate that: (a) selection for birth weight may increase drip loss, lightness of longissimus dorsi, and gluteus medius muscles but may reduce fat depth; (b) selection for nursery weight can be valuable for increasing both quantity and quality traits; (c) selection for increased daily gain may increase the carcass weight and most of the primal cuts. These findings suggest that deterioration of pork quality may have occurred over many generations through the selection for less backfat thickness, and feed efficiency, but selection for growth had no adverse effects on pork quality. The heritabilities of carcass and pork quality traits indicated that they can be improved through traditional selection and genomic selection, respectively. The estimated genetic parameters for performance, carcass and meat quality traits can be incorporated into the breeding programs that emphasize product quality in these Canadian swine populations. In the third study, a genomic selection was performed for meat quality and carcass traits in 2,100 commercial pigs and 107 Duroc purebred pigs using Illumina’s PorcineSNP60 BeadChip and single-step BLUP (ssBLUP). It was concluded that genomic predictions models developed using ssBLUP could predict the parental purebreds without substantial loss of prediction accuracy compared to their crossbred progenies to improve carcass and pork quality traits. The prediction accuracies for the purebred parental resulted from the ssBLUP evaluation were also compared with the accuracies from the traditional parental average. The results showed that the prediction accuracies resulted from the ssBLUP had average improvements of 17% and 16% for pork quality and carcass, respectively. In conclusion, this study confirmed that genomics could improve pork quality through genomic selection from commercial crossbred pigs to meet the demands by consumers, packers and processors.
Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
Citation for previous publication
Miar, Y., G. S. Plastow, H. L. Bruce, S. S. Moore, G. Manafiazar, P. Charagu, R. A. Kemp, B. Van Haandel, R. B. McKay, A. E. Huisman, C. Y. Zhang, and Z. Wang. 2014. Genetic Relationships between Performance with Meat Quality and Carcass Characteristics in Commercial Crossbred Pigs. PLOS ONE, 9(10): e110105. DOI: 10.1371/journal.pone.0110105.Miar, Y., G. S. Plastow, H. L. Bruce, S. S. Moore, G. Manafiazar, P. Charagu, R. A. Kemp, B. Van Haandel, R. B. McKay, C. Y. Zhang, A. E. Huisman, and Z. Wang. 2014. Genetic and Phenotypic Parameters for Carcass and Meat Quality Traits in Commercial Crossbred Pigs. Journal of Animal Science, 92(7):2869-84.Miar Y, GS Plastow, Z Wang (2014) Genomic Selection, a new era for improvement of meat quality. Springer Science Reviews (Submitted)Miar Y, GS Plastow, HL Bruce, RA Kemp, P Charagu, CY Zhang, AE Huisman, Z Wang (2014) Genomic Selection of Pork pH in Purebred Pigs for Crossbred Performance. 10th World Congress on Genetics Applied to Livestock Production (WCGALP), Vancouver, British Columbia, CANADA, Aug. 17-22, 2014.

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