Goose breeding has a traditional role in the Hungarian agriculture. Goose breeders are concerned in improving the fertility using artificial insemination with frozen sperm.

The aim of the study was to find such freezing protocol which can be carried out at a cheap rate in practical circumstances.

Two basic freezing methods were compared: (A) programmable protocol with a freezing rate of -40°C/min and a simple freezing in nitrogen vapor (B). In both methods the preparation of pooled semen samples were made at 5°C. On the basis of preliminary investigations 5 min equilibration time and 40 °C thawing temperatures were applied.

Combinations of various cryo- and osmoprotectants were tested. Dimetil-formamide in different concentrations was used as basic cryoprotectant. In both methods four-four treatments were used: in programmable freezing (1) 7% DMF, (2) 10% DMF, (3) 10% DMF+0,1M betaine, (4) 10% DMF+3% trehalose+3% sucrose, while in nitrogen vapor method: (1) 9% DMF, (2) 12% DMF, (3) 12% DMF+0,1M betaine, (4) 12% DMF+3% trehalose+3% sucrose. The efficiency of the methods was examined by in vitro tests.

In the case of programmable freezing (A) treatment (1) (7% DMF) resulted significantly (p≤0.01) lower survival rate of live, intact spermatozoa compared to the protocols 2, 3 and 4 (42,6; 47,9; 48,5; 50,3%, respectively). The osmoprotectants slightly but not significantly improved the sperm survival in (A) protocols.

Among the nitrogen vapor protocols (B) no significant differences were found in survival rates (43-46%).

Since in both methods over 40% sperm survival could be achieved, the simple nitrogen vapor protocol seems to be promising tool in the practice. 10-12% DMF is necessary for acceptable protective effect. Contrary to our expectations neither betaine nor trehalose-sucrose combination could improve significantly the survival of frozen gander sperm.

Keywords: sperm freezing, gander, cryo- and osmoprotectants