Association between molecular markers for beef tenderness and growth traits in Argentinian angus cattle

Molecular markers for beef tenderness are classic examples of the contribution of genome technology to animal breeding through marker-assisted selection (MAS). Markers on the μ-calpain (CAPN1) and calpastatin (CAST) genes have been extensively evaluated for their association with tenderness. However, little is known about their potential effect on other economically important traits. In this work, the association of molecular markers for beef tenderness with growth traits was evaluated in Angus cattle of Argentina. Expected progeny differences were extracted from the 2008 Angus Sire Summary of Argentina. Information corresponding to 268 influential bulls that had been genotyped for two markers in CAPN1 and two markers in CAST was provided by the Argentine Angus Association. Genotype probabilities were assigned, by segregation analysis, to those bulls in the Sire Summary that had no marker information. Expected progeny differences of 1365 sires were regressed on the number of alleles favouring tenderness at each locus. There was a significant effect of markers on expected progeny differences of birth weight, weaning weight (direct), weight at 18 months and rib eye area. In general, there was a negative effect of alleles favouring tenderness on growth traits. These correlated responses should be taken into account when molecular markers are used in selection schemes that aim to improve beef tenderness.