Background: The aim of this study was to get information on post mortem diagnoses of sows found dead or euthanised and to understand the diagnoses aetiology (causative background). Moreover, the study was to evaluate the association between the clinical symptoms observed on farm and post mortem findings.

Puberty traits of 740 Yorkshire gilts from a selection experiment were analyzed. Heritabilities were estimated to be .32 for pubertal age, .23 for length of proestrus, .16 for length of standing estrus, .29 for ability to show standing reflex, and .24 for intensity of vulvar symptoms. Genetic correlations between length of proestrus, intensity of vulvar symptoms, and ability to show standing reflex were positive. There seemed to be a negative genetic correlation between percentage of lean and intensity of vulvar symptoms. There were negative genetic correlations between growth rate and length of standing estrus, and between growth rate and ability to show standing reflex.

The study comprises observations in 464 Swedish Yorkshire pigs at puberty and after the first weaning. The aim was to study relationships between age at puberty and weaning to estrus interval and between estrus signs at puberty and after the first weaning. The estrus signs were checked, and blood samples for progesterone determination were drawn regularly around puberty and after the first weaning. Gilts expressing early puberty (youngest one-third) showed a greater ability to return to estrus and to ovulate within 10 d after weaning than gilts expressing late puberty (oldest one-third) (P = .01). A positive genetic correlation was found between age at puberty and the interval from weaning to the first detected estrus (WEI) (rg = .45). The genetic correlation between age at puberty and the ability to show the standing reflex and to ovulate within 10 d after weaning was negative (rg = -.50). The heritability of the ability to show the standing reflex and to ovulate within 10 d after weaning was .31. Gilts not showing a standing reflex at puberty also had a higher incidence of ovulation without a standing reflex within 10 days after their first weaning (21.4 vs 6.2%, P = .001). There was a significant positive correlation between the total duration and the intensity of the reddening and swelling of the vulva at puberty and after the first weaning. This study demonstrates relationships both between age at puberty and WEI and between some estrus signs at puberty and after the first weaning.

Porcine reproductive and respiratory syndrome (PRRS) is characterized by reproductive failure in sows and respiratory problems in growing pigs. The disease is present in most countries throughout the world but was not diagnosed in Sweden until the summer of 2007 when it was first detected through the national PRRS surveillance program. The immediate mobilization of veterinary authorities, field veterinarians and the pig industry was a prerequisite for preventing the spread of the disease. Within 10 days seven herds were verified as infected and the measures taken included stamping out, cleaning, disinfection and a vacancy period of 3 weeks before the herds were repopulated. To evaluate the effectiveness of these measures, a national sero-surveillance was carried out during the autumn of 2007. Approximately 90% of the pig production was covered by this screening and all samples tested were negative with regard to antibodies to PRRS virus.

S-755 97 Uppsala, Sweden. A genetic study of pubertal age, litter traits, weight loss during lactation and relations to growth and leanness in gilts.