Background: Cryopreservation of bovine semen affects survival of spermatozoa. It is necessary to improve semen quality to increase fertility. The aim was to determine the effect of α-tocopherol added to the bovine semen diluent at different time of freezing, upon sperm quality post thawing.
Methods: Semen was collected from Charolais breed bulls. The semen was divided into two portions and one portion was added with α-tocopherol and the other was used as control. These portions were further divided into three parts and frozen for 8, 11 and 15 minutes, respectively. After 60 days of cryopreservation, the progressive motility, non-progressive motility, absence of motility, vitality and DNA fragmentation were evaluated. Result: The lower percentages of DNA fragmentation were treated with antioxidants (15.52, 14.83 and 14.71%). The highest vitality and progressive motility were found in the sample with α-tocopherol and frozen for 11 min with 72.91 and 58.61%, respectively. The addition of α-tocopherol to the semen diluent decreased damages to spermatozoa and enhanced the semen quality.