1 Introduction

In contrary to most domestic birds, geese have a short seasonal reproductive cycle, but they can be used as the breeding flock for up to 4-6 years of age without evident decrease in fertility potency^[1-4]. Although it has been indicated that even 14 years old ganders are still able to produce semen and females to laid eggs (Lukaszewiczl, 1997, unpublished data), for economic reasons, it is generally accepted to keep the breeding geese for 3-4 years.

2 Materials and methods

2.1 Animals

Two groups of 9 White Italian (Anser anser) ganders each were used. The One-Year Group consisted of ganders of 9 months old and the Two-Year Group, ganders of 2 year-old. Semen was collected three times a week by the dorso-abdominal massage method at the same time (9:30-10:00 AM) and by the same three technicians. Animals were placed in individual cages for the whole reproductive season. The reproductive season of the 2-year-old animals starts at the end of December to the second decade of June next year; the younger animals start a little later. The caged ganders had visual and acoustic contact with the females, and were housed under natural light and fed with the commercial food for breeding geese, 400-500 g per day per bird.

2.2 Semen examination

Routine semen examination, including semen volume, color, and consistency, sperm motility, concentration and morphology, and blood or fecal contamination, was performed with the freshly collected semen.

Sperm concentration was estimated with a hemocytometer, motility, by visual scoring on microscope slides, and morphology, on smears stained with nigrosin-eosin and examined under oil immersion objective (1250). Dead spermatozoa are stained with the dye, but not the viable ones. In each smear, 300 spermatozoa were counted and classified into the following categories:
0 - Viable spermatozoa in total (including forms 1-6).
1 - Viable spermatozoa with normal morphology (typical spindle-shaped head and well-marked acrosome, and each part of the spermatozoa blends into the other, from head to tail).
2 - Bulb-head spermatozoa.
3 - Crocked-necked spermatozoa (with broken head-midpiece junction).
4 - Spermatozoa with changed midpiece (lack of mitochondrial sheath, with swollen or slightly pinkish midpiece).
5 - Immature spermatozoa.
6 - Spermatozoa with other deformities.
7 - Dead spermatozoa (completely or partially stained spermatozoa)

2.3 Statistical analysis

4 Conclusions

Proper selection and training of ganders for semen collection procedure prior to the onset of experiment was essential for obtaining good quality and clean semen during the observation period. However, due to the specific structure of the copulatory organ in the ganders, ejaculates contaminated with feces and urine were occasionally encountered. The present data suggest that spermatogenesis in young gander may not be fully matured with the production of low quality semen. However, for the documentation of this observation further investigation is required. The lower quality semen produced by younger ganders may be to some extent compensated by a higher ejaculate volume and higher sperm concentration. 

Since at the first half of the reproductive season, ganders of both groups produce semen of higher quality and quantity, more frequent semen collection (say every other day) for artificial insemination may be practiced. At the second half of the reproductive season semen collection should be reduced to twice a week.