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

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. 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. 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