Bioscientifica Proceedings

Summary. In many species the appearance of oestrus is sufficient to ensure that the time of ejaculation, sperm transport and capacitation are balanced with the time of ovulation. In the pig these phenomena vary considerably and require additional regulatory mechanisms which are partly explained by seminal components.Boar semen is rich in oestrogens (up to 11.5 μg/ejaculate). Infusion of saline with the addition of oestrogens in ph...

Summary. In the wild pig mating activity is seasonal. The main breeding period is in late autumn but a second period may occur around April. It is known from other species that seasonal variations in breeding activity are mainly regulated by photoperiod.In the domestic pig seasonal influences on prolificacy still exist: for example, Al boars not only show decreased steroid synthesis, sperm counts and libido in summer compared with t...