Description:
<jats:p>The aim of the work was to study a potential relationship between acrosome response characteristics of bovine spermatozoa and their ability to fertilize oocytes and produce <jats:italic>in vitro</jats:italic> embryos. Sperm of artificial insemination bulls with a high rate (22.0 ± 4.1%, group A, <jats:italic>n</jats:italic> = 7) or a low rate (10.3 ± 4.1%, group B, <jats:italic>n</jats:italic> = 8) of embryos were used. For acrosome assessment, motile spermatozoa from a Percoll gradient were incubated with or without heparin and examined by the fix-vital sperm assay (FVSA). The differences between the heparin-treated (H<jats:sup>+</jats:sup>) and the non-treated (H<jats:sup>−</jats:sup>) spermatozoa were significant (<jats:italic>p</jats:italic> < 0.01) in all bulls at all tested intervals. According to the kinetics of the heparin response, the bulls fell into three categories: fast (FR, <jats:italic>n</jats:italic> = 7), moderate (MR, <jats:italic>n</jats:italic> = 5) or slow (SR, <jats:italic>n</jats:italic> = 3) acrosome responses (<jats:italic>p</jats:italic> < 0.01). Five MR bulls were found in group A in comparison with two MR bulls in group B (57.1 vs 12.5%; <jats:italic>p</jats:italic> < 0.05). Intensity of the acrosome response (response index) was significantly higher in bull group A compared with bull group B (7.0 vs 4.6, <jats:italic>p</jats:italic> < 0.01). A positive correlation was recorded between response index and embryo rate (<jats:italic>r</jats:italic> = 0.668, <jats:italic>p</jats:italic> < 0.01). In conclusion (<jats:italic>a</jats:italic>) the kinetics of spermatozoa response to heparin may be important for <jats:italic>in vitro</jats:italic> fertilization, bulls with a moderate response appearing to be most suitable for embryo production; (<jats:italic>b</jats:italic>) greater spermatozoa response to heparin was related to more effective embryo production.</jats:p>