Characteristics of fresh gander semen and its susceptibility to cryopreservation in six generations derived from geese inseminated with frozen-thawed semen.

The paper summarises seven years experiments designed to determine the effect of continuous insemination with frozen-thawed semen on fresh semen quality and sperm susceptibility to freezing stress in succeeding generations. During course of experiments, semen was collected from 10-12 White Koluda ganders at the age of 8-9 months, then subjected to freezing and used after thawing for insemination of 10 geese in order to obtain the subsequent generation of males. Semen was diluted 1 to 0.5 (v/v) with EK diluent, equilibrated for 15 min at +4 degrees C, mixed with 6 percent (v/v) of dimethyl-formamide (DMF), frozen to temp. -140 degrees C at a rate 60 degree C per min and then transferred into liquid nitrogen container. Semen samples were thawed prior to insemination in a 60 degree C water-bath. It is difficult to conclude whether freezing stress affected the fresh semen quality, since average volume of SQF (index comprising ejaculate volume, sperm concentration and percentage of live normal cells) varied between generations from 19.3 to 56.2. Continuous goose reproduction by insemination with frozen-thawed semen resulted in significant increase (P less than 0.01) in spermatozoa resistance to cryoinjury in every subsequent generation. In the relation to adequate fresh semen the percentage of live morphologically intact spermatozoa which withstood freezing procedure increased from 27.2 in first generation to 74.4 in sixth generation.