Departamento de Fisiología, Facultad de Veterinaria, Lasplaces 1550, Montevideo, Uruguay.
Anim Reprod Sci. 2010 Aug;121(1-2):101-5. doi: 10.1016/j.anireprosci.2010.05.007. Epub 2010 May 20.
Reproductive performance of rams when they were 1.5 and 2.5 years old during two breeding seasons was investigated. The objective was to compare the reproductive performance of the rams on the basis of their social ranks, which had been scored for each subject during the lamb development stage. The subjects were aged matched Corriedale x Milchschaf rams (n=12: all singles born during the same week from multiparous ewes) were used. Data were collected from the five rams with greater (GR) and lesser (LR) social rank scores when lambs. These data included body weight, scrotal circumference, sexual behavior toward estrual ewes (e.g. incidence of ano-genital sniffing, lateral approaches, Flehmen, mount attempts, actual mounts, and mounts with ejaculations, and ejaculation/total mount ratio) during a 30-min period, and semen variables (semen volume, mass motility, individual sperm motility and total number of spermatozoa in the ejaculate). During the first breeding season, GR rams were heavier (62.9+/-2.7 kg) than LR rams (69.4+/-3.0 kg; P<0.0001). There were no differences in scrotal circumference or testosterone concentration measures. Semen volume was greater in GR rams (0.5+/-0.1 mL compared to 0.7+/-0.1 mL for GR and LR rams; P<0.004), but it tended to have a greater percentage of abnormal spermatozoa. Although some courtship behaviors were more frequent in LR rams (lateral approaches and Flehmen) and ejaculation/total mount ratio of LR rams also tended to be greater, mounting activity (mount attempts and mounts) was more frequent in GR rams. During the second year, GR rams still tended to be heavier (83.3+/-2.0 kg compared to 85.9+/-2.4 kg; P=0.09) but had smaller scrotal circumference than LR rams (37.5+/-0.2 cm compared to 36.5+/-0.6 cm; P<0.045). Semen characteristics were not different for the rams, but mass motility tended to be greater for LR rams. Generally, LR rams displayed more lateral approaches, showed Flehmen more often, mounted with ejaculation more often, and tended to have a greater mount with ejaculation/total mounts ratio. Conclusions were courtship of rams may differ in line with the social status they had as lambs although there are not clear effects on other sexual behaviors or semen characteristics.
在两个繁殖季节中，研究了 1.5 岁和 2.5 岁的公羊的繁殖性能。目的是根据公羊在羔羊发育阶段的社会等级对其繁殖性能进行比较。研究对象为年龄匹配的 Corriedale x Milchschaf 公羊（n=12：均为来自多胎母羊的同周单胎羔羊）。收集了羔羊时期社会等级评分较高（GR）和较低（LR）的 5 只公羊的数据。这些数据包括体重、阴囊周长、公羊对发情母羊的性行为（例如，有无肛生殖器嗅探、侧面接近、Flehmen 反应、爬跨尝试、实际爬跨、有射精的爬跨以及射精/总爬跨次数比）、精液变量（精液量、精子总活力、个体精子活力和每次射精的精子总数）。在第一个繁殖季节，GR 公羊（62.9+/-2.7 kg）比 LR 公羊（69.4+/-3.0 kg；P<0.0001）更重。阴囊周长或睾酮浓度测量没有差异。GR 公羊的精液量更大（0.5+/-0.1 mL 与 GR 和 LR 公羊的 0.7+/-0.1 mL 相比；P<0.004），但精子畸形率较高。尽管 LR 公羊的一些求爱行为更频繁（侧面接近和 Flehmen 反应），而且 LR 公羊的射精/总爬跨次数比也更高，但 GR 公羊的爬跨活动（爬跨尝试和爬跨）更频繁。在第二年，GR 公羊仍然更重（83.3+/-2.0 kg 与 85.9+/-2.4 kg 相比；P=0.09），但阴囊周长比 LR 公羊小（37.5+/-0.2 cm 与 36.5+/-0.6 cm 相比；P<0.045）。公羊的精液特征没有差异，但 LR 公羊的总活力较高。一般来说，LR 公羊的侧面接近次数更多，更频繁地表现出 Flehmen 反应，射精爬跨次数更多，射精/总爬跨次数比更高。结论是公羊的求爱行为可能会因它们在羔羊时期的社会地位而有所不同，尽管这对其他性行为或精液特征没有明显影响。
