Effect of collection rhythms and season on rabbit semen production.

The effects of collection regimen and time of year on rabbit semen production were determined in this study. A total of 14 crossbreed Hyla bucks were used in winter and summer. In each season, rabbits were assigned to two groups. In group 1, (n = 7) rabbits were subjected to an extensive collection regimen (two ejaculates per male, once daily/week) and in group 2, (n = 7) a semi-intensive semen collection regimen was performed (two ejaculates per male, twice weekly). The traits recorded for each sample were libido, volume, pH, motility, sperm concentration, percentage of alive spermatozoa and sperm abnormalities. The results obtained in this study indicate that when increasing collection frequency, the rate of useful collections decreased (from 0.81 +/- 0.017 to 0.69 +/- 0.016; p < 0.01). The rate of useful collection also decreased in the transition from winter to summer (from 0.79 +/- 0.018 to 0.70 +/- 0.017; p < 0.01). Among the ejaculate characteristics studied, only volume/ejaculate (from 0.64 +/- 0.015 to 0.53 +/- 0.017; p < 0.01) and spermatozoa/ml (from 406 +/- 15 to 359 +/- 13 million; p < 0.01) appeared negatively affected by collection. In winter fewer volume/ejaculates were produced (0.55 +/- 0.015 vs 0.60 +/- 0.016 ml; p < 0.01) and fewer spermatozoa/ml (360 +/- 14 vs 394 +/- 16 million; p < 0.01) than in summer. The doses produced per ejaculate decreased as collection frequency increased, but the number of doses produced per week was higher in the semi-intensive than the extensive rhythm (26.5 +/- 2.1 vs 20.9 +/- 1.5; p < 0.01). The results suggest that a semi-intensive rhythm may be viewed favourably.