Cryopreservation of gander semen in cryovials - Comparative study

The aim of the study was to find a practical and inexpensive method for freezing goose semen for use in routine inseminations under farm conditions. Two basic freezing protocols [(1) dynamic, programmable freezing and (2) static, nitrogen vapour method] were evaluated with varying concentrations of dimethylformamide (DMF) plus additional osmoprotectants such as betaine, trehalose, and sucrose, using cryovials as containers. Altogether eight different treatments were compared. sperm viability before freezing and after thawing was examined by in vitro tests and, in the case of the simplest effective method, also by in vivo fertility test. There were no significant differences in sperm survival either in the dynamic (48-50%) or in the static protocol (43-46%), except for the treatment where the lowest DMF concentration was used without any osmoprotectant in the dynamic protocol (42.6%). The addition of osmoprotectants did not improve thawed sperm viability in any case. Fertility with frozen/thawed sperm using the simplest method was 58.5%, while that obtained with fresh, diluted semen was 66.9%. The study proved that the simple freezing of gander semen in nitrogen vapour with 9% DMF in cryovials could produce acceptable fertility. The newly elaborated method can be successfully used for routine inseminations by small- and large-scale goose breeders.