Genetic parameters for large-scale behavior traits and type traits in Charolais beef cows1

Abstract

In the last decades, beef cattle breeding mainly focused on improving production and reproduction traits. Nowadays, there is a growing interest to include behavior and type traits in the breeding goal. There is an interest in behavior as it is associated with human safety and workability and in type traits as they might be associated with longevity of cows. The objective of the current study was to estimate the heritability for behavior and type traits in Charolais and to estimate the genetic correlations among these traits. Behavior traits, including aggressiveness at parturition, aggressiveness during gestation period, and maternal care, were scored by farmers using an on-farm recording system to enable large-scale collection of phenotypes. Type traits, including udder traits ( = 3), teat traits (3), feet and leg traits (5), and locomotion (1), were scored by 10 trained classifiers. Data was available on 6,649 cows in parity 1 to 12 and located in 380 herds. Results showed that differences between herds explained up to 23% of the total phenotypic variance in behavior traits. This might be due to differences in management or to consistent differences in scoring between farmers. Aggressiveness at parturition had higher heritability (0.19) and higher genetic coefficient of variation (CV = 11%) than aggressiveness during gestation ( = 0.06 and CV = 4%) and maternal care ( = 0.02 and CV = 2%). Heritabilities for udder traits (0.14 to 0.20) and teat traits (0.17 to 0.35) were higher than for feet and leg traits (0.02 to 0.19). Genetic coefficients of variation for udder and teat traits were also higher (up to 21%) than for feet and leg traits (up to 11%). Strong genetic correlations were found between behavior traits (with absolute values from 0.71 to 0.98). The genetic correlations indicate that it is difficulty to simultaneously improve maternal care and reduce aggressiveness. We concluded that there are good opportunities to implement selection for improved udder and teat traits and against aggressiveness at parturition using a simple on-farm recording system of behavior.