Estimation of Genetic Parameters for Economic Traits of Hanwoo Cows Using Ultrasound

This experiment was conducted to estimate the genetic parameters and breeding values of the economic traits measured from the cows (aged 15 months or older) using ultrasound and to use them as the information for the selection of stock animals at the farm level. The means and standard deviations of longissimus muscle area, backfat thickness and marbling score were $54.11\;cm^2{\pm}9.06$, $3.57\;mm{\pm}2.45$ and $2.65{\pm}2.88$, respectively. While the linear regression coefficients of longissimus muscle area, backfat thickness and marbling score for age (in months) were all positive (0.3532, 0.0868 and 0.0833), the quadratic regression coefficients of them for age (in months) were all negative (-0.0023, -0.0005 and -0.0006), and as the body condition score increased longissimus muscle area, backfat thickness and marbling score increased collectively. The heritability estimates for the longissimus muscle area, backfat thickness and marbling score were 0.39, 0.48 and 0.13, respectively and the estimated annual genetic gains for the longissimus muscle area, backfat thickness and marbling score were 0.00334 $cm^2$, -0.0073 mm and 0.0043 score, respectively, which were not significantly different from zero.