The objective of this study was to determine the optimal inclusion level of ascorbic acid in TRIS-yolk extenders for cryopreservation of goat semen. We used five ejaculates of three Anglo Nubian goats. Semen from each animal was divided into four 200μL aliquots, composing four treatments: no addition of ascorbic acid (control) and 0.0528, 0.1056, and 0.1584mg/mL of ascorbic acid in TRIS-egg yolk. We evaluated motility and sperm vigor after dilution, post-cooling, and post-thawing; membrane integrity (HOST); acrosomal integrity, and slow thermoresistance test (TRT). Data were subjected to regression analysis at 5% probability. There was no difference for the progressive motility and sperm vigor, respectively, in the post-dilution, after cooling and post-thawing, as well as the additional tests HOST and after 120 minutes of TRT, for motility and force, respectively, in post-thawing (P>0.05). There was a quadratic effect with the addition of ascorbic acid to the acrosome integrity parameter, presenting a great maximum level of 0.1006 mg/mL ascorbic acid for acrosome integrity of 61.58% (P<0.05). The addition of ascorbic acid was effective in maintaining sperm viability, especially acrosome integrity during the cryopreservation process until the level of 0.1006 mg/mL, and it may be an alternative composition of seminal extenders for goats.Keywords: antioxidants; oxidative stress; sperm; TRIS-yolk
