Perkins A, Fitzgerald J A
Department of Animal Science, University of California, Davis 95616.
J Anim Sci. 1994 Jan;72(1):51-5. doi: 10.2527/1994.72151x.
The objective of this study was to test whether the sexual behavior of the ram affects the ram effect. Rams exhibiting either high (HP) or low (LP) levels of sexual performance (on the basis of serving capacity tests) were exposed to 89 anestrous ewes for 28 d. Thirty-two anestrous ewes were not exposed to rams. The objective of this study was to compare the efficacy of estrus induction by HP (n = 4) vs LP (n = 4) rams. Plasma progesterone concentration was used as an index of ovarian activity. Groups of ewes were exposed to either an HP or an LP ram in a .32-ha pasture. Courtship behaviors of rams were recorded for 6 h on the initial day of exposure and for 30-min periods on alternate days thereafter. A greater percentage of ewes exposed to HP rams ovulated (95%) compared with ewes exposed to LP rams (78%) (P < .02). On the 1st d of exposure, the HP rams exhibited more courtship behavior and spent more time near the ewes (P < .04). The HP rams spent more time within 1 m of ewes during the 28-d exposure. There were no differences in the amount of contact with rams (LP or HP) between rise in progesterone indicate of ovulation tended to occur earlier (P = .06) in ewes penned with HP rams. A greater percentage of ewes exposed to LP rams (P = .03) had early elevations of progesterone with no concurrent sexual behavior. These data imply that in addition to a pheromone the sexual behavior of the ram may be important in initiating ovarian cycle activity.
本研究的目的是测试公羊的性行为是否会影响公羊效应。根据输精能力测试，将表现出高（HP）或低（LP）性行为水平的公羊与89只处于乏情期的母羊接触28天。32只乏情期母羊未接触公羊。本研究的目的是比较HP（n = 4）公羊与LP（n = 4）公羊诱导发情的效果。血浆孕酮浓度用作卵巢活动的指标。将母羊分组，在0.32公顷的牧场中接触HP或LP公羊。在接触的第一天记录公羊的求偶行为6小时，此后隔天记录30分钟。与接触LP公羊的母羊（78%）相比，接触HP公羊的母羊排卵的比例更高（95%）（P < 0.02）。在接触的第一天，HP公羊表现出更多的求偶行为，在母羊附近停留的时间更长（P < 0.04）。在28天的接触期间，HP公羊在距离母羊1米范围内停留的时间更长。接触LP或HP公羊的母羊之间在接触量上没有差异，孕酮升高表明排卵倾向于在与HP公羊圈养的母羊中更早发生（P = 0.06）。接触LP公羊的母羊中有更高比例（P = 0.03）孕酮早期升高且无同时发生的性行为。这些数据表明，除了信息素外，公羊的性行为在启动卵巢周期活动中可能也很重要。
