Effect of various antioxidants and their combinations on bull semen cryopreservation

Our objective was to evaluate the effects of adding 50 mM trehalose (TRE), 1 mM cysteine (CYS), or 400 µg catalase (CAT), individually or in combinations, to a Tris-based semen extender and determine the effects on fresh, chilled-equilibrated, and frozen-thawed bull sperm. Ejaculates from three Holstein bulls (1-3 years old) were pooled, divided into six equal portions, and put into a Tris-based extender supplemented with no additive (control), TRE, CYS, CAT, TRE + CYS, or TRE + CYS + CAT. In chilled-equilibrated semen, motility was highest in CAT but lowest in the control (P