Effect of age on quality of fresh and frozen-thawed semen in White Italian ganders.

Aim: To comparatively evaluate the fresh semen quality of 1, 2 and 3-yr-old White Italian ganders (Anser anser L.) and the susceptibility of spermatozoa to freezing-thawing procedure.

Methods: Semen was collected by dorso-abdominal massage every 2 days~3 days from three groups of ganders: 1-yr-old (n=11), 2-yr-old (n=7) and 3-yr-old (n=9). In the pooled fresh semen samples, the following parameters were evaluated: the ejaculate volume, the blood or feca contamination and the motility, concentration and morphology of spermatozoa. Sperm motility and morphology were evaluated in the frozen-thawed semen. Semen diluted with EK extender was frozen in straws in a computerized freezing unit with 6 % dimethyl-formamide to -140 deg at a rate 60 deg/min and then transferred into the LN2 container. Straws with semen were thawed in a water bath at 60 deg.

Results: The ejaculate volume decreased with the age (0.21 mL for 1-yr-old, 0.18 mL for 2-yr-old and 0.14 mL for 3-yr-old ganders); the sperm concentration increased with the age (327 x 10(6) mL(-1) for 1-yr-old, 431 x 10(6) mL(-1) for 2-yr-old and 547x10(6) mL(-1) for 3-yr-old ganders); the number of live - normal sperm was significantly (P<0.01) lower in the 1-yr-old than that in the 2- and 3-yr-old ganders (26.61 %, 41.54 and 35.9 %, respectively). The percentage of normal cells survived the freezing-thawing process was 37.7 %, 43.3 % and 40.9 % for 1-, 2- and 3-yr-old ganders, respectively.

Conclusion: Freezing and thawing processes more significantly (P<0.01) affected the motility, viability and morphology of spermatozoa in semen of 1-yr-old ganders in comparison with older males.