Assessment of different on-farm measures of beef cattle temperament for use in genetic evaluation.

The aim of this study was to find a simple measure for calf temperament discrimination, which can be useful as a selection criterion for on-farm French beef cattle breeding schemes. Behavioral records were registered at an average age of 5 and 7 mo, respectively, for 1,282 and 1,440 Limousin calves born in 24 French farms between August 2007 and April 2008. Measures were repeated for 810 calves at the 2 ages. The test procedure consisted of individually restraining the calves in a chute, then exposing them to a stationary human situated in front of the chute for 10 s. For every calf and each period of the test, the number of rush movements and the total number of movements were scored by visual appraisal using a continuous scale ranging from 0 (no movements) to 60 (continuous movements). Initial scores were also transformed to categorical scores and analyzed. Genetic correlation across ages were very high for all the traits (above 0.84 ± 0.20) suggesting that these traits are governed by the same pool of genes at the 2 ages. The corresponding phenotypic correlations were about 0.3 for all the measures. Heritabilities were moderate for all measures (from 0.11 to 0.31) with the total number of movements during weighing measured at 7 mo being the greatest. All the measures were highly correlated (from 0.73 ± 0.26 to 0.99 ± 0.02). Genetic correlation across sexes was not statistically different from 1. However, traits measured during weighing showed different genetic variance estimates for females and males. Similar results were obtained for the transformed categorical scores. According to these results, the total number of movements during weighing seems to be the most promising trait for on-farm genetic evaluation of French beef cattle temperament.