Ejaculates from six boars of Danish Landrace were divided into four parts, I, II, III and IV which were treated in the following way: I was diluted 1:4-1:6 with EDTA-diluter, and filled into glass vials (single doses). II was centrifugated at 1800-2000 r.p.m. in 12-15 min.; the centifugate was resuspended in the supernatant and diluted as indicated under I. III and IV were centrifugated at 1800-2000 r.p.m. in 12-15 min. The supernatant was removed by aspiration and the centrifugate diluted with as much EDTA-diluter necessary to produce the same no, of doses of 10 ml as was produced from I and II respectively. The diluted semen was stored at 18-20 degrees C and used on the day of collection. Just before insemination the semen from I, II and III was diluted with IVT-diluter to a final volume of 75 ml. Semen from IV was diluted to the same volume with IVT-diluter with the addition of 50% boar seminal plasma, procured by centrifugation of ejaculates from other boars of the A.I. Centre, and stored at divided by 20 degrees C until use. The results have been set out in Table I. Inseminations with semen from I and II resulted in pregnancy rates of 84,6% and 86,3% and average litter sizes of 10,3 and 10,1 for sows and 9,1 and 9,6 for gilts; inseminations with semen from III and IV resulted in pregnancy rates of 78,9 and 78,2% and average litter sizes of 10,5 and 10,7 for sows and 10,0 and 8,7 for gilts. None of the differences in pregnancy rates between groups were significant. The findings were: 1. By insemination with initially diluted semen without seminal plasma a tendency to a decline in pregnancy rates could be demonstrated. 2. The decline persisted after the addition of 50% boar seminal plasma to the diluter used for the final dilution just before insemination.
PIP: Results are reported of an experiment which researhes the effect that addition of seminal plasma to diluted semen can have on the rate of fertilization. the ejaculates from 6 boars were divided into 4 groups. Group 1 was used as a control, and was dilated 1:4-1:6 with EDTA; this semen had an 84.6% impregnantion rate. The rest of the ejaculate was centrifuged at 1800-2000 rpm for 12-15 minutes. Group 2 consisted of the centrifugate resuspended in the supernatent; this group had an 86.3% impregnation rate. Group 3 consisted of the centrifugate dilated only with IVT; this group had an impregnation rate of 78.9%. Group 4 consisted of the centrifugate combined with IVT and 50% boar seminal plasma; this group had a 78.2% impregnantion rate. There were no significant differences between the pregnancy rates or the litter sizes among any of the groups. boar seminal plasma does not seem to have a positive effect on the fertilization rate of diluted semen.