Wplyw pory roku na jakosc mrozonego nasienia trykow polskiej owcy dlugowelnistej

The quality of the frozen semen of the Polish Longwool Sheep was investigated in the work in the year cycle as well as the freezing usability of the two diluents: citrate-yolk-fructose as well as lactose. The studies were carried out on the 9 rams in the age of 2—3 years from which the semen was taken twice a month. Then the semen was frozen in the aluminium tubes of the volume approximately 2 cm³. The semen was thawed at 38—40°C from 30 sec. It was found that the quality of the fresh and frozen semen was the best in July-September and the worst in March-June. After thawing of the semen the progressive movement of spermatozoa in these periods was 34—36% and 20—25%, respectively, percentage of spermatozoons with intact acrosome 30—38% and 25—30% and time of survival of spermatozoons at 38°C 7.0—7.7 h and 5.5—6.5 h, respectively. The used diluents have not affected significantly the freezing usability of the semen. Ram semen, however, appeared to be very sensitive to freezing and thawing. Comparing to the fresh semen the percentage of spermatozoons of progressive movement and spermatozoons with intact acrosomes diminished more than twice in thawed semen.