Influence of Diluents and Processing Times After Ejaculation on the Survival of Deep-Frozen Ram Spermatozoa

Abstract

SummarySamples of semen were cooled to 5°C over 2 hr and stored for 1· 5, 5· 0, or 16·7 hr prior to freezing. Best revival was obtained after the 16·7 ·hr period.In a factorial experiment the time taken to cool semen from 30 to 5°C and from 5 to -40°C, the glycerol concentration of the diluent, and the equilibration period were varied. Increasing the glycerol concentration from O' 51 to 1· 01M increased the mean scores of percentage motile, but lowered the mean counts of percentage unstained spermatozoa observed upon thawing. A O' 5·hr equilibration period was better when samples were frozen in O· 51M glycerol, but a period of 5·0 hr was better when 1· 01M glycerol was used. Semen cooled to 5°C over 3 hr revived better than samples cooled over 1 or 2 hr. However, 0·5 hr equilibration was better than 5·0 hr for semen samples cooled to 5°C over 3 hr, whilst the longer period of equilibration was better for samples cooled to 5°C over 1 hr. Further, approximately the same results were obtained for samples cooled to 5°C over 1 or 3 hr and frozen at 1 degC/min, whilst cooling to 5°C over 3 hr was better when the samples were cooled below 5°C at 4 degC/min. When 1, 2, 3, or 4 hr elapsed from the initial dilution of semen at 30°C and with glycerolation 20 min prior to freezing, best revival was observed in samples cooled to 5°C over 2 hr rather than 1 or 3 hr.Spermatozoa frozen in skim milk revived better than spermatozoa frozen in a lactose synthetic medium, and samples frozen in reconstituted skim milk survived incubation at 37°C after thawing better in a similar diluent containing no glycerol than in a diluent based on Krebs-Henseleit-Ringer.

Koç Spermasının Dondurulmasında Kullanılan Soğutma Oranlarının Membran Bütünlüğü ve Motilite Özelliklerine Etkisi

“…cooling rate negatively affected total or progressive motility during different stages of the cryopreservation process, but when the cooling rate was raised to 0.9°C/min in all stages of the process the total and the progressive motility were affected negatively. Similar to our findings, Jones [26] showed that raising the cooling time of the spermatozoa from 30 to 5°C from 1 h to 2 and 3 h, obtained better post-thaw motility (respectively 36.9%, 44.8% and 47.9%, P<0.001).…”