Interpretive Summary: Heritability and genetic correlations of feed intake, body weight gain, residual gain, and residual feed intake of beef cattle as heifers and cows.
By: Jackie Walling
Feed is the largest cost in beef production and feed intake is thought to be a heritable trait. Information about genetic evaluations for feed intake in growing heifers and mature cows is minimal. A recent study in the 2020 January issue of the Journal of Animal Science estimates the heritability of feed intake, body weight gain, residual gain, and residual intake in growing heifers and mature cows. Genetic correlations of these measurements also were evaluated.
Individual feed intake and BW gain were measured for 687 heifers and 622 five-year-old cows, breeds varied. The study model represented feed intake associated with maintenance and BW gain. Average daily gain (ADG) and average daily dry matter intake (ADDMI) were calculated, while residual feed intake (RFI) and residual average daily gain (RADG) reported restricted indices that indicated feed efficiency.
Results found heritability of ADDMI was 0.84 for heifers and 0.53 for cows, heifers’ results were higher than previous reports. Heritability of ADG was 0.53 and 0.34, respectively. Genetic correlations between heifers and cows for ADDMI and ADG were 0.84 and 0.73, respectively. Heritability of RFI and RADG for heifers and cows were all 0.25 or under.
Overall, metabolic rate and BW gain drive feed intake. In the long run this study could help determine selections in breeding. Selection for cattle needing less feed to produce weight gain could reduce feed costs. Heritability and genetic correlations between ADG and feed intake (0.86) was higher than most reports. Breed differences for feed intake were reported for heifers, but not mature cows. The genetic correlation between ADG and ADDMI was high which suggests selecting cows for a lower feed intake would also reduce ADG in mature cows.
For the full article, visit the Journal of Animal Science.