FERTILITY OF FROZEN-THAWED BOAR SEMEN

Farrowing results of six fertility tests are presented. Semen was processed by removal of seminal plasma and addition of glycerol at 30°C before (method A) or after (method B) stepwise cooling to 5°C, and by the Beltsville method (C). Sperm concentrations at freezing were 0·9 × 109/ml (A and B) and 0·6 × 109/ml (C). Farrowing rates for semen processed by methods A and B and pellet-frozen in tris-fructose-EDTA (TFE) diluent were 11/16 and 9/16 (farrowed/inseminated, mean 62·5%), and 10/16 for both single and double inseminations (10 × 109 amd 20 × 109 total motile sperm respectively). When equal numbers of motile spermatozoa from semen processed by method A were deposited by single and double inseminations, farrowing rates for sperm doses of 1·25 × 109, 2·50 × 109 and 5·00 × 109 were 7/16,7/16 and 12/17 respectively (mean 53·1%), and 11/20 and 12/20 (mean 57·5%) for doses of 5 × 109 and 10 × 109 respectively. Number of inseminations within sperm dose had no effect on fertility. Pregnancies for semen processed by method A and frozen as pellets (0·25 ml) or in plastic bottles (30 ml) were 6/16 and 2/16, and after single insemination of 10 × 109 motile spermatozoa by non-fractionated and fractionated methods 6/16 and 2/16 respectively. Farrowing for semen pellet-frozen by method C in Beltsville F5(BF5) extender was 5/10 after double insemination with 6 × 109 total (motile and non-motile) spermatozoa per dose. Fertility rates for semen processed by method A, pellet-frozen in TFE or Beltsville F3 (BF3) diluents and stored for one year were 4/10 and 3/10 respectively (mean 35 %) after single insemination of 10 × 109 motile spermatozoa. The mean litter size for the total of 89 sows farrowing was 9.4 ° 2.9. © 1979 ASEG.