Early sexual experience improves ram breeding

Abstract

A ram responds to olfactory stimuli from an estrous ewe by exhibiting the Flehman response. Ram lambs exposed to ewes shortly after puberty (8-9 months of age) attained more successful matings as yearlings than rams that were 20 months old when first exposed to estrous ewes. Research on the development of sexual behavior in male sheep has demonstrated that ram lambs are sufficiently mature in their first year of life to assume an important role in sheep-breeding programs. Lack of sexual experience in the first year can result in sexual inactivity, reduced mating rates, and abnormal sexual orientation in the yearling year. Variability in rams' sexual performance can be evaluated by simple mating tests administered prior to the breeding season. The greater reproductive success of high-performing rams is achieved not only by a higher rate of mating but also by a tendency to distribute matings over more females. High libido rams are not inherently more aggressive. Sheep producers welcome new ideas to improve the efficiency of their sheep breeding programs. Our research on the sexual behavior of male sheep at UC Davis and the UC Hopland Research and Extension Center is designed to provide new insights into the reproductive management of rams by investigating: (1) the development of sexual behavior; (2) methods of evaluating sexual performance; and (3) other traits that may influence sexual performance.