EFFECT OF MATING ON THE ONSET AND DURATION OF OVULATION IN THE SOW

Abstract

Mating has been shown to have effects on ovulation in a number of species which ovulate spontaneously, such as rats (Aron, Asch & Asch, 1961; Aron, Asch & Ross, 1966; Zarrow & Clark, 1968) and sheep (Parsons, Hunter & Rayner, 1967; Van der Westhuysen, Van Niekerk & Hunter, 1970). In the sow, the results obtained by Pitkjanen (1955) and Lebedev (1957) suggest that mating hastens ovulations and shortens the time during which ova are liberated. Direct inspection of the ovaries by coelioscopy (Locatelli, 1971) allows rapid and accurate determination of the time of ovulation and causes minimal trauma. By this technique, the earlier results have been confirmed in a preliminary experiment (Signoret, 1970). The present experiment was designed to show by how many hours mating advances ovulation and shortens its total duration. Fifty-nine Large