Freezing of boar semen is highly desirable; However, to date there have been no encouraging results for its use in the production of pigs for supply due to the damage that sperm suffer during the freezing-thawing process due to oxidative stress that impairs fertilizing characteristics such as motility, viability And acrosomal integrity (NAR). The objective of this work was to evaluate the effect of the addition of antioxidants (vitamin C, E and their combination) on the sperm quality (motility, viability and NAR) of frozen-thawed semen of boar in two types of straws. York boar semen was used. As a diluent, MR-A was used for semen transport. For the freezing the Westendorf method was used with some modifications in straws of 0.25 and 0.50 ml. Before freezing, vitamins C, E and C + E were added at concentrations of 1, 2 and 4 mg / ml. Thawing was performed seven days later. The best results were: With vitamin C at a concentration of 4 mg / ml in straws of 0.25 ml, 0%, 41% and 40% of motility, viability and NAR, respectively; In straws of 0.5 ml was 63%, 95% and 80% of motility, viability and NAR, respectively. With vitamin E at a concentration of 2 mg / ml, in straws of 0.25 ml, 40%, 66% and 73% of motility, viability and NAR, respectively, were obtained; In straws of 0.50 ml, 40%, 60% and 55% of motility, viability and NAR, respectively, were obtained. With the combination of vitamins C + E at a concentration of 1 mg / ml in straws of 0.25 ml, 0%, 47% and 60% of motility, viability and NAR, respectively, were obtained; In straws of 0.50ml, was obtained, 0%, 42% and 47% of motility, viability and NAR. In conclusion, the best results were with vitamins C and E, separately as antioxidants in straws of 0.50ml.
