Dominance, hierarchy, and reproduction in rams and goat bucks

The reproductive results in sheep or goat flocks is consequence of multiple factors, including the interactions between males, and how these interactions modify the sexual behavior of other males. The present review summarizes information on the dominance relationships between rams or bucks, and how these relationships affect their reproductive outcomes. Dominance relationships affect the access of some males to estrous females, influencing the total distribution of sperm among the flock. The review provides information on how dominance relationships are established during the development period, and also after mixing previously unknown males. The period of relationships establishment is extremely stressful for rams and bucks, and destabilize the social relationships, affecting even sperm quality. Dominant and subordinate males display different strategies to impregnate females, but females also participate in mate choice decisions with proceptive behaviors, selecting subordinate males, favoring the maintenance of genetic diversity. Although a high proportion of ewes that lamb twins may be impregnated by different males, there is still scarce information on how these interactions affect the final distribution of paternities. Overall, although males’ interactions have important consequences on reproduction and genetic improvement, there is still the need for more knowledge on the practical consequences of social interactions.