Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: February 5, 2001
Publication Date: March 20, 2001
Citation: Casas, E., Stone, R.T., Keele, J.W., Shackelford, S.D., Kappes, S.M., Koohmaraie, M. 2001. A comprehensive search for quantitative trait loci affecting growth and carcass composition of cattle segregating alternative forms of the myostatin gene [Abstract]. Journal of Animal Science Supplement. 79(2):40. Technical Abstract: Effects of the bovine myostatin gene and additional quantitative trait loci (QTL) have been assessed. The objective of this study was to identify further QTL for economically important traits. Two half-sib families were developed from a Belgian Blue x MARC III (n=246) and a Piedmontese x Angus (n=209) sire. Traits analyzed were birth, weaning, and yearling weight (kg); preweaning average daily gain (kg/d); postweaning average daily gain (kg/d); hot carcass weight (kg); fat depth (cm); marbling score; longissimus muscle area (cm2); estimated kidney, pelvic, and heart fat (%); USDA yield grade; retail product yield (%); fat yield (%); and wholesale rib-fat yield (%). Meat tenderness was measured as Warner-Bratzler shear force (kg) at 3 and 14 d postmortem. A total of 89 markers were used. In the family of Belgian Blue inheritance, a significant QTL (expected number of false positives=0.025; ENFP) was identified for marbling score on chromosome 3. Suggestive QTL for the same family (ENFP=0.5) were identifie for retail product yield on chromosome 3, for hot carcass weight and postweaning average daily gain on chromosome 4, for fat depth and marbling score on chromosome 8, for 14-d Warner-Bratzler shear force on chromosome 9, and for marbling score on chromosome 10. Evidence suggesting the presence of an interaction for 3-d Warner-Bratzler shear force between the myostatin gene and a QTL on chromosome 4 was detected. In the family of Piedmontese and Angus inheritance, evidence indicates the presence of an interaction for fat depth between the myostatin gene and chromosome 8. Regions underlying QTL need to be assessed in other populations. The myostatin gene has a considerable effect, but other loci with subtle effects are involved in the expression of the phenotype.