title: [A pig farm with chronic fertility problems].
abstract: A herd with 320 sows with chronic fertility problems is described. About 20 to 30% of the inseminated sows returned to oestrus, for unknown reasons. When the interval from insemination to return to oestrus was analysed, it appeared that 20% of the sows returned between 24 and 28 days. A thorough and extensive control of the pig-farmer's oestrus detection technique revealed that nearly all sows were inseminated between 4 to 6 days post-weaning. However, this was too early for a number of sows. These sows showed optimal oestrus symptoms 6-8 days post-weaning. This was also the explanation for the high number of sows returning to oestrus 'irregularly' between 24 and 28 days. Thus when analysing insemination intervals, the interval between 24 and 35 days should not be considered as one period but should be divided into the periods, 24-28 days and 29-35 days. In this way it is possible to distinguish between sows inseminated too early and sows returning to oestrus irregularly.
authors.affiliation: Kliniek Voortplanting, Verloskunde en Bedrijfsdiergeneeskunde, Faculteit Diergeneeskunde, Gent, België.
authors.forename: A
authors.initials: A
authors.lastname: de Kruif
authors.forename: A
authors.initials: A
authors.lastname: Lein
mesh_terms: D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D004972:Estrus Detection / Q000662:veterinary; D005260:Female; D007247:Infertility, Female / Q000209:etiology*; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary*; D008297:Male; D013552:Swine / Q000502:physiology*; D013997:Time Factors
vernacular_title: Een varkensbedrijf met jarenlange fertiliteitsproblemen.