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

  • Author / Creator
    Miar, Younes
  • 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.

  • Subjects / Keywords
  • Graduation date
    Spring 2015
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
  • Specialization
    • Animal Science
  • Supervisor / co-supervisor and their department(s)
  • Examining committee members and their departments
    • Bruce, Heather (Agricultural, Food, and Nutritional Science)
    • Dixon, Walter (Agricultural, Food, and Nutritional Science; examiner external to the supervisory committee)
    • Plastow, Graham (Agricultural, Food, and Nutritional Science)
    • Ernst, Catherine (Michigan State university; external examiner)
    • Korver, Doug (Agricultural, Food, and Nutritional Science; examination chair)