Influence of season and frequency of ejaculation on production of stallion semen for freezing.

In an attempt to define optimal season and ejaculation frequency for frozen semen, semen was collected from 6 stallions (3 horses and 3 ponies) 3 times per week or every day, alternating every week, for 1 year. The semen was evaluated and frozen. All the samples were thawed at the end of the experiment. At collection, fresh semen evaluations showed that winter (as opposed to spring and summer) was associated with low sexual behaviour, small volumes of spermatozoa and gel, high sperm concentration and lower motility. The high ejaculation frequency yielded a decreased volume, concentration of spermatozoa in the ejaculate and slightly improved motility. The quality of thawed semen was analysed by video and microscope estimations for motility and by two staining methods for vitality. No variation was observed according to the ejaculation frequency; the best freezability was obtained in winter but the difference was small compared to between-stallion variability and optimization of frequency and season did not change a 'bad freezer' into a good one.