Abstract :
This study was undertaken to investigate the influence of thawing period on some post-thaw semen characteristics of Holstein bulls following adding catalase to Tris extender. Five Holstein bulls of 2.5-3 years old were used in this experiment. Semen was collected via artificial vagina at once ejaculate per bull per week for seven weeks experimental period. Pooled semen was equally divided into two groups using Tris extender. Catalase (100 IU/ml) was added to Tris extender as compared with control group (Tris extender). Following one year cryopreservation period, straws were thawed at 37˚C and examined after different thawing time (15, 30, 60 and 120 minutes). Sperm individual motility, live sperm percentage and total sperm abnormality were investigated. Sperm individual motility were superior (P≤ 0.04-P≤ 0.08) in catalase as compared with the control group during all thawing time. However, 15 and 30 minutes exhibited the highest (P≤ 0.002) motility percentage in catalase group. Similarly, higher live sperm percentage was noticed in catalase as compared with control group. The 15 and 30 minutes being the better live percentage for both groups. In contrast, the differences between groups in sperm abnormality percentage lacked significance. The least abnormality percentage was observed following 15 minutes and the highest at 120 minutes thawing time for both groups. In conclusion, the addition of catalase to Tris extender led to improved post-thaw sperm individual motility and live percentage of Holstein bulls following 15 and 30 minutes thawing period. This will in turn enhance fertility rate of artificially-inseminated cows, and owner s economic income consequently.
