Genet. Sel. Evol.
Volume 37, Number 4, July-August 2005
|Page(s)||381 - 401|
Genetic analysis of emotional reactivity in sheep: effects of the genotypes of the lambs and of their damsAlain Boissya, Jacques Bouixb, Pierre Orgeurc, Pascal Poindronc, Bernard Bibéb and Pierre Le Neindrea
a Unité de Recherches sur les Herbivores ACS, INRA, 63122 Saint-Genès Champanelle, France
b Station d'amélioration génétique des animaux, INRA, 31326 Castanet-Tolosan, France
c Physiologie de la Reproduction et des Comportements, UMR85 INRA-CNRS-HN-University, 37380 Nouzilly, France
(Received 5 July 2004; accepted 24 March 2005)
Abstract - A total of 1347 weaned lambs from eight genotypes were tested over five consecutive years: Romanov (ROM) and Lacaune (LAC) pure breeds, the two F1 crossbreeds (RL and LR) and the offspring of ewes from these four genotypes sired with Berrichon-du-Cher rams (BCF). The lambs were individually exposed to three challenging tests involving novelty, human contact and social isolation. Ten synthetic variables were used to express social reactivity (i.e., active vs. passive strategy), exploratory activity and reactivity to humans. BCF crossbreds were more active (i.e., high bleats, locomotion and attempts to escape) than purebreds and F1. In contrast, ROM expressed more passive responses (i.e., low bleats and vigilance postures) than LAC and BCF crossbreds. In addition, ROM approached a motionless human less and had longer flight distances to an approaching human than did LAC and BCF crossbreds. When restrained, ROM, and to a lesser extent BROM and BLR, avoided human contact more than did LAC, RL and BLAC. Most of these differences were explained by direct additive genetic effects while maternal influences or heterosis effects were rarely significant. The highest heritability was for high bleats ( h2=0.48). Females were more active and avoided human contact more than did males.
Key words: genetics / emotional reactivity / human contact / social isolation / sheep
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© INRA, EDP Sciences 2005