Genetic parameters between sexes for temperament traits in Limousin cattle

Genetic selection based on reduced cattle fearfulness to increase their adaptative abilities to human environments could be an important way to improve both animal welfare and breeders' working conditions. In particular, improving temperament of cattle breeds that are difficult to handle is a major concern especially in extensive ranching breeding conditions where extremes in temperament are displayed more often. Consequently, in the last decade, selection for improving temperament on farm has become one of the main objectives for the Limousin cattle reared in Australia, New Zealand or in North America. Selection has been mainly based on a crush test (Tier et al., 2001). In France, there is currently no test on farms, but Limousin bulls have been evaluated since 1990 on a "docility test" (Boivin et al., 1992) in an individual test station and in a female progeny test station for bulls going through the AI breeding program. A few studies have reported a significant sex effect on temperament traits, with females always more excitable or difficult to handle (Voisinet et al., 1997; Lanier et al.., 2000; Gauly et al., 2001). As far as we know, there had been no genetic analysis to test whether reaction to human handling was governed by the same pool of genes between sexes. Because different neuroendocrine mechanisms may be involved in the fear reactions of females and males, the aim of the study was to assess the potential genetic differences between sexes for temperament traits recorded in French and Australian Limousin cattle.