Understanding motility dynamics of crossbred bull spermatozoa when analyzed by Computer Assisted Semen Analyzer (CASA)

The study was conducted to understand sperm kinetics of Frieswal bull spermatozoa using Computer Assisted Semen Analyzer (CASA). Fifty bull ejaculates were collected from ten healthy bulls that were in routine semen collection. The semen samples were diluted in Tris buffer at a concentration of 25x10⁶ spermatozoa/ml for analysis. Rapidly moving spermatozoa represented the one with better velocity and progressiveness while spermatozoa with medium motility had low velocity with short distance travelled in spite of its ability to move in a straight line (straightness, STR >70%). The slow moving cells had good head and flagella movement but they followed a circular path with straight line velocity (VSL μm/sec), linearity (LIN %) and straightenss (STR %) of 10.91, 9.00 and 22.54, respectively. Results indicated that individual sperm cells tracked by CASAas rapid, medium and slow motile were highly variable (p<0.001). However, thesperm motilitybetween bulls varied (p<0.05) only in lateral head displacement (ALH, μm) and beat cross frequency (BCF, Hz).