Control of swine parturition. 1. Results of clinical, histological and hematological studies of parturition induction in swine using prostaglandin F2 alpha

Parturition was induced to 23 sows on the 112th day of pregnancy by intramuscular injection of 7.5 mg PGF2 alpha (Dinoprost-Upjohn Co.). Onset of parturition was achieved within 27 hours and 52 minutes +/- four hours and 54 minutes in 21 animals (91.3 per cent). Average litter size was 11.33 piglets, with parturition time per litter having been five hours and 45 minutes +/- two hours and 39 minutes. Stillbirths accounted for 6.3 per cent. The average birth weight, 1.245 g +/- 264 g did not differ with significance from that of the controls. The physiological process accompanying parturition is described in greater detail. Unobstructed re-intergration with further reproduction of animals which had received PGF2 alpha treatment is established with hard evidence on the basis of clinical examination of oestrus, ovulation, conception, and farrowing rates as well as by histological examination of the endometrium. Alterations in the blood state recorded from animals with PGF2 alpha treatment close to full term were identical with those recorded from untreated animals.