Direct and Correlated Responses to Selection for Intramuscular
Fat in Duroc Swine
At the present state of technology, intramuscular fat percentage can be accurately evaluated in live pigs and utilized in conjunction with sib carcass data for estimation of breeding values for intramuscular fat. Within the population under study, selection on resulting EBV has yielded a significant phenotypic change in all measures of IMF. Phenotypic gain in IMF established through selection in the current study resulted in IMF levels that may be useful for differentiation of sire lines for use in muscle quality-based niche markets. Results from this study illustrate that phenotypic improvement of IMF may correspond to an increase in objective tenderness, and shed light into the possible ramifications of this response in measures of carcass composition. Intramuscular fat may be used in swine breeding programs as an indicator of general product palatability; however, sensory characteristic improvements are likely to be slow when simultaneous improvement in other trait categories is also pursued.