Polyspermy of pig ova

Abstract

Of 168 pronucleate ova recovered from sows killed at varying intervals after mating (0, 24, 30 and 48 hours), 20 showed more than 2 pronuclei; 19 of these were recovered from sows in which mating was delayed until 30 to 48 hours after the onset of heat. Evidence is presented that polyspermic fertilisation is responsible for the appearance of ova with more than 2 pronuclei. It is concluded that delayed mating increases the frequency of polyspermic fertilisation in pigs and this might be a source of embryonic mortality in pigs inseminated artificially.