Genetic parameters of pork quality traits

Traits of longissimus dorsi meat quality, nutritional composition and eating quality were included with growth and carcass traits in this evaluation. The growth and carcass traits evaluated were leg soundness score, average daily gain, dressing percentage, carcass longissimus dorsi area at tenth rib, carcass off midline backfat at tenth rib, carcass midline backfat at last rib, carcass midline backfat at last lumbar, and carcass length;Meat quality, composition, and eating quality traits of the longissimus dorsi taken from the tenth to twelfth rib section of the carcass are marbling score, color score, firmness score, Minolta Y reflectance, ultimate pH, protein solubility, pigment, tenderness score, juiciness score, chewiness score, flavor score, Instron tenderness, cooking loss, cooked moisture content, raw and cooked total lipid percent, raw and cooked cholesterol content, and seven fatty acids (myristic, palmitic, palmitoleic, stearic, oleic, linoleic and arachidonic). Heritabilities and genetic correlations among these traits give swine breeders a guide to weighting traits for a selection objective;The effects and interactions of eight breeds, two sexes (barrow and gilt) and two halothane genotypes (Normal and Heterozygote) are reported for all traits. All test pigs were typed for halothane genotype by a DNA marker;Variance components for heritabilities and genetic correlations were estimated with the multiple trait derivative free restricted maximum likelihood (MTDFREML) computer programs distributed by USDA-ARS;Meat quality and eating quality traits have moderate heritability and are genetically correlated to carcass traits such as backfat thickness and longissimus dorsi area. There was a negative relationship between carcass backfat and eating quality traits of total lipid content, tenderness, juiciness and cooked moisture content;Heterozygote halothane genotype pigs grew slower, had less backfat, more longissimus dorsi area, and paler color, poorer tenderness and juiciness scores, less total lipid content of the longissimus dorsi than normal pigs;Longissimus dorsi from Hampshire pigs had significantly lower ultimate pH while those from Berkshire pigs had significantly higher ultimate pH. These research results support the \u27Hampshire effect\u27 reported by other researchers. Berkshire pigs produced the most tender cooked longissimus dorsi sections;Heritabilities of longissimus muscle fatty acid composition varied from.43 to.68