Comparative study on semen quality of one- and two-year-old ganders duringthe entire reproductive season

Aim: To evaluate the characteristics of semen produced by one- and two-year s old White Italian ganders during the entire reproductive season, in order to clarify whether the young ganders are responsible for a low fertility r ate in young geese. Methods: Males were kept individually in cages under na tural light. Semen was collected by dorso-abdominal massage three times a w eek and routine examination was performed. Results: The mean ejaculate volu me (2.1 and 1.6 mL, respectively) and sperm concentration (323 and 281 x 10 (6)/mL, respectively) in one-year-old ganders were higher than those of two -year-old ones. The percentages viable spermatozoa of one- and two-year-old ganders were similar (91.4 and 92.3%, respectively), but the percentage of normally formed viable spermatozoa was significantly higher in the older g anders than in the younger (47.8 and 42.9%, respectively, P <0.05). Conclus ion: The semina from one or two-year-old Ganders were similar in regard to volume, sperm density and sperm motility, but the percentage of normally fo rmed viable spermatozoa, which is critical for fertilization, was significa ntly higher in the older ganders. It appears that the ganders an responsibl e for the low fertility rate in young geese.