Genetic parameters for productive, reproductive, growth and morphological traits in Mertolenga cattle

Abstract

Mertolenga is the largest of Portugal’s native cattle breeds. Estimating genetic parameters and analyzing trait correlations are essential for breeding programs. This study assessed genetic parameters for reproductive, growth, production and morphological traits and conducted univariate and multivariate analyses using the BLUP Animal Model and MTDFREML program. The heritability (h2) estimated for calving interval (CI) was 0.06 ± 0.001 and it has a strong negative correlation (- 0.89 ± 0.001) with total number of calvings (TNC), which has an h2 of 0.26 ± 0.01. Age at first calving (AFC) has an h2 of 0.30 ± 0.01 and has a moderate negative correlation (- 0.40 ± 0.005) with productive longevity (PL) and TNC (-0.43 ± 0.005), which have h2 of 0.27 ± 0.01 and 0.26 ± 0.01, respectively. The h2 and correlation estimates between the direct and maternal effects in weaning weight were 0.31 ± 0.05, 0.22 ± 0.02 and - 0.30 ± 0.04, respectively. Carcass weight per day of age showed an h2 of 0.40 ± 0.02. Average daily gain (ADG) had an h2 of 0.21 ± 0.08, a moderate and negative correlation (-0.65 ± 0.167) with feed conversion ratio (FCR) and a strong positive correlation (0.87 ± 0.057) with relative growth rate (RGR). ADG shows a weaker relationship (- 0.34 ± 0.937) with residual feed intake (RFI), which has an h2 of 0.35 ± 0.08. Morphological traits had generally low heritabilities, and traits in the same body region showed moderate to high genetic correlations. The traits studied showed reasonable genetic variability supporting the potential for improving the Mertolenga breed through selection.