External and internal modulators of sheep reproduction

SUMMARY Several factors such as season, genetics, social interaction and metabolic status control or modulate the reproductive capacity of sheep. In addition to these well-studied factors in sheep, the infl uence of emotional reactivity on the reproductive success of sheep has started to be investigated over the last two decades. In this paper, after briefl y reviewing the impact of classical factors affecting reproduction in sheep, we defi ne emotional reactivity and the expression of its inter-individual variability, named temperament. Then, following a description of the protocol to measure temperament in sheep and discussion on the heritability of temperament traits, we illustrate how this selection affects the reproductive biology of sheep. We will be mainly using results obtained from a unique fl ock of sheep selected for low or high emotional reactivity. In conclusion, we propose that energy partitioning could be one of the mechanisms by which selection for temperament 1