[Anaphrodisia in gilts and sows(author's transl)]

The economy of pig breeding and rearing farms is determined mainly by the fertility of the animals. Anaphrodisia causes a considerable disturbance of the fertility. This has a direct effect on the number of litters born per sow per year and thus on the economic results. On the basis of several years of experience at the research station and the production unit of Varkensonderzoekcentrum Nieuw-Dalland the clinical symptoms in gilts and sows are described. Gilts should normally have come into oestrus at the age of about 8 months, and on a well-managed farm about 80% of the sows should come into oestrus within 10 days of weaning, provided that weaning takes place at 5 to 6 weeks. Different forms of anaphrodisia are described, based on the findings of post mortem examinations. These show that in 65-75% of the anaphrodisiac animals the ovaries were insufficiently active. In 20% of the animals that had not shown signs of oestrus, ovulation had in fact taken place. The causes of anaphrodisia must be sought in a disturbance of the hypothalamo-hypophysial ovarian system, in which genetic and health factors play an important role, besides housing and management (insluding feeding). A good keeping of records of sows is indispensable in the solving of the anaphrodisia problem on farms, and this hinges also on an analysis of the farm management and on the power of observation of the farmer. Finally, hormonal therapy is discussed, a distinction being made between breeding and rearing farms.