Changes in the qualities of stallion semen after incubation with Streptococcus zooepidemicus

The influence of ß-haemolytic Streptococcus organisms at concentrations of 100 x, 200 x, and 500 x 10³ cells/ml sperm incubated at 37°C for 60 min with stallion semen suspension on the motility, viability and morphology of the semen, and AspAT activity in seminal plasma was examined. S. zooepidemicus at a concentration of 500 x 10³ cells/ml exhibited a particularly unfavourable effect on semen. All parameters measured altered significantly after a 60 min incubation. The activity of AspAT also changed during a prolonged incubation of sperm with a suspension containing 500 x 10³ S. zooepidemicus/ml semen; after a 24 h incubation the activity of AspAT was enhanced by more than 38% in comparison to the initial value.