[Seasonal changes in spermatozoas and fertility of stallions in the tropics]

An attempt was made to express the relationship of spermiological characteristics with the fertility on the basis of seasonal variability of the fertility of stallions and of the ejaculate quality. A positive correlation between the activity of spermatozoa and the fertility ensues from the values of correlation coefficients. There is a negative correlation between the fertility and the concentration of citric acid. In the other characteristics, i.e. in the production of spermatozoa, volume of gel substance, pH, ergothioneine concentration, polarographic and hemolytic activity, the correlation coefficients were very low. It is assumed that these characteristics may influence the livability and preservation of the sperm, but they do not affect its fertilizing ability.