Heritability and genetic correlation of body weight and Kleiber ratio in Limousin and Charolais beef cattle breeds

•This study embraces two factors for the cost-benefit ratio of rearing cattle.•Kleiber ratio is an alternative option for cattle selection regarding feed efficiency.•Kleiber ratio is a tool that disregards the measurement of individual feed intake.•The genetic variability of the Kleiber ratio allows satisfactory genetic gains.•The selection over Kleiber ratio has no effects on body weight.