Submitted to: European Association of Animal Production Proceedings
Publication Type: Other
Publication Acceptance Date: 8/1/2000
Publication Date: 8/1/2000
Citation: SHORT, R., MACNEIL, M.D., GROSZ, M.D., GRINGS, E.E. EFFECTS OF MUSCULARITY ON PELVIC AREA AND EFFICIENCY IN HEREFORD, LIMOUSIN,AND PIEDMONTESE F2 CROSSBRED CALVES GENOTYPED FOR THE PIEDMONTESE MYOSTATINALLELE. EUROPEAN ASSOCIATION OF ANIMAL PRODUCTION PROCEEDINGS. Aug. 21-24. 2000. 4 pgs. Interpretive Summary: Increased production of lean beef with a concurrent decrease in fat while maintaining tenderness can be accomplished to a moderate degree by utilizing breeds such as Limousin. An even more dramatic effect can be obtained by using the mutant myostatin (msP) allele associated with Piedmontese that causes muscular hypertrophy. Increased dystocia related to msP is caused by a combination of increased birth weight and decreased pelvic area. Depressions of gain reported earlier with Piedmontese-cross cattle were shown to be not associated with the muscular hypertrophy allele, and decreased efficiency of live weight gain in Piedmontese is offset when adjusted for meat yield. A major portion of the gene action of the msP allele for traits related to muscle development is additive. Opportunities exist to exploit the positive effects of increased muscularity through appropriate breeding programs using moderate increased muscularity and muscle hypertrophied genotypes.
Technical Abstract: Similar body weight genotypes, especially double muscled, that differ in muscularity may differ in traits other than muscularity. To test this hypothesis, Hereford (normal muscling, H), Limousin (moderate muscling, L) and Piedmontese (double muscled, P) sires (20 to 25 per breed) were bred to crossbred cows to produce F1 calves which were inter se mated within sire breed to produce F2 calves. P-cross F2 calves were genotyped for the G-A transition mutation at the myostatin locus characteristic of P (msP), and their genotypes were classified on the basis of having 0 (P0), 1 (P1) or 2 (P2) copies of the mutant P allele. Parents of P-cross F2 calves were assumed to be P1, and H and L F2 calves were assumed to be ms normal (H0, L0). Pelvic area (PA) was measured at slaughter and was affected by genotype (P<.01) with most of the effect resulting from a larger PA in P0 with a progressive decrease as msP alleles were added (N and PA, cm**2, for H0, L0, P0, P1 and P2, respectively, were 69, 171; 60, 175; 19, 185; 32, 175 and 15, 168). Live weight gain (G, kg) and food intake (metabolisable energy, ME, Mcal and crude protein, CP, kg) were measured during a 90 or 132 day finishing period which started at 338 kg for heifers and 383 kg for steers. G was highest in L0 and lowest in P (P<.01) with no effects of the msP allele. ME and CP intake were highest in P0 and lowest in P2 (P<.05). N, G, ME and CP for H0, L0, P0, P1 and P2, respectively, were 135, 109, 2443, 109; 136, 115, 2415, 108; 30, 101, 2512, 113; 82, 102, 2505, 112 and 28, 101, 2325, 104.