An observational study into herd-level risk indicators of return to oestrus more than five days after insemination in sow herds.

In a study population of 90 sow herds in the southern Netherlands, the occurrence of sows returning to oestrus more than five days after insemination (SRO) was investigated. In these herds information with regard to the herd system, herd size, and breeding management was recorded. The occurrence of SRO was recorded with the on-farm computer management system CBK-plus. The incidence of SRO was defined as the average number of gilts or sows returning to oestrus more than five days after insemination per 100 first inseminations. The average incidence of SRO in the study population was 18.3 per 100 first inseminations. Multivariate analysis resulted in a model with a significant effect of herd operation (herds with only sows had a lower incidence of SRO than herds with sows and finishing pigs), breeding strategy (herds with two or more inseminations per oestrus in a sow had a lower incidence of SRO than herds with one insemination per oestrus) and percentage of sows artificially inseminated (a higher percentage of artificial insemination was associated with a higher incidence of SRO).

Return to oestrus after first insemination in sow herds (incidence, seasonality, and association with reproductivity and some blood parameters).

As no systematic study has been done to get an accurate estimate of the incidence of return to oestrus after first insemination in sows in the Netherlands, the objectives of this investigation were: 1) to obtain an estimate of the incidence of return to oestrus after insemination at the herd level; 2) to investigate the association between incidence of return to oestrus after first insemination and reproduction characteristics in order to get an impression of the economic importance of reproductive failure. These objectives were investigated by using the reproduction results of 240 swine breeding herds in the Southern Netherlands in 1987. This information was obtained from CBK plus computerized herd management records. The average incidence rate of return to oestrus after first insemination at a herd level was 16.9 per 100 first inseminations. The occurrence of return to oestrus after first insemination was distinctly higher in the insemination months July and August compared to the rest of the year. An increased incidence, with 10 returns per 100 first inseminations corrected for confounders in a multiple linear regression model, was associated with a decrease of approximately 0.3 live born piglets/sow/year. A prospective longitudinal study was started in 1988 and 1989 in 37 sow herds. Individual sows were monitored from weaning to first insemination, to the occurrence of return to oestrus, or not, after first insemination, and to farrowing. The investigation focused in particular on the relationship between return to oestrus after first insemination and seroconversion against porcine parvovirus (PPV) and Leptospira interrogans serovar bratislava (L. bratislava).(ABSTRACT TRUNCATED AT 250 WORDS)

Haematology and biochemistry reference values for sows kept under modern management conditions.

The data presented here were obtained using blood samples from 159 healthy, conventionally managed sows from 37 breeding herds. Sows were sampled at weaning and at 4-5 weeks gestation. Paired blood samples were analysed from sows that had a normal pregnancy and subsequently farrowed. The mean values of serum total protein, albumin and gamma globulin concentration were lower in the blood samples obtained at weaning compared with those obtained at 4-5 weeks gestation. Leucocyte count was higher, mostly as a result of a higher segmented neutrophil count, in the blood samples obtained at weaning compared with those obtained at 4-5 weeks gestation.

[Return to estrus following first insemination in sow herds (incidence and association with reproductivity and various blood parameters)]. / Terugkomen na eerste inseminatie op zeugenbedrijven (incidentie en associatie met reproduktiviteit en een aantal bloedparameters).

As no systematic study has been done to get an accurate estimate of the incidence of return to oestrus after first insemination in sows in the Netherlands, the objectives of this investigation were: 1) to obtain an estimate of the incidence of return to oestrus after insemination at the herd level; 2) to investigate the association between incidence of return to oestrus after first insemination and reproduction characteristics to get an impression of the economic importance. These objectives were investigated using the reproduction results of 240 swine breeding herds in The Southern Netherlands in 1987, using their CBK plus computerized herd management records. The average incidence of return to oestrus after first insemination on a herd level was 16.9 per 100 first inseminations. An increase of incidence with 10 returns per 100 first inseminations, corrected for confounders in a multiple linear regression model, was associated with a decrease of approximately 0.3 liveborn piglets/sow/year. Thereupon individual sows were followed in 1988 and 1989 prospectively in 37 sow herds from weaning to insemination, returning to oestrus or not after first insemination to farrowing. The investigation focused in particular on the relationship between returning to oestrus after first insemination and incident infection with porcine parvovirus (PPV) and Leptospira interrogans serovar bratislava (L. bratislava). During a number of consecutive farm visits sows were blood sampled at weaning and again a blood sample was taken 6 weeks later. The final dataset that was analysed consisted of 161 animals that did not return to oestrus after first insemination and 158 animals that returned to oestrus after first insemination.(ABSTRACT TRUNCATED AT 250 WORDS)