Genetic parameters for growth and carcass traits in Japanese brown cattle estimated from field records.

Field records from 14,380 Japanese Brown steers by 92 sires were used to estimate genetic parameters for growth and carcass traits. Multipletrait restricted maximum likelihood (REML) procedures accounting for relationships among sires were used in estimating (co)variance components among average daily gain during fattening periods (ADG), carcass weight (CWT), longissimus muscle area (LMA), rib thickness (RT), marbling score (MS), and subcutaneous fat thickness (SFT). Heritability estimates on an age-constant basis were .22, .37, .38, .26, .40, and .35 for ADG, CWT, LMA, RT, MS, and SFT, respectively. Estimated genetic correlations (rg) among ADG, CWT, and RT were positive and moderately high (.48 to .85). The rg between MS and SFT was -.12.