Background: Sperm cryopreservation is necessary for genetic sharing on a national and international scale. Objective: This study aimed to examine, after treatment with various antioxidants, the link between buck age and sperm quality using the computer-assisted sperm analysis (CASA) method. Material and methods: Collected semen from 16 younger and 14 older New Zealand rabbit bucks. The obtained semen was assessed by the CASA system using ejaculates with at least 70% progressive motility. Separated semen samples into eight liquors and diluted (1:1 v/v) with rabbit semen extender supplemented with all antioxidant combinations (melatonin (M), L-carnitine (LC), cysteine (Cys), LC+M, M+Cys, LC+Cys, and LC+Cys+M) and untreated group. Results: The casa's characteristics were higher in young than older bucks. In comparison to controls, which recorded the lowest values, the addition of antioxidants increases total and progressive sperm motility in all experimental groups significantly. All experimental group's antioxidant supplementation levels and the control group were significantly lower than fresh pooled semen. Additionally, all CASA parameters increased compared to the control group when buck semen was supplemented with different antioxidants. Conclusion: In contrast to younger bucks, administering several antioxidants (LM, LS, MS, and LMS) has a more substantial positive effect on sperm motility and CASA parameters in older bucks. Thus, age has a substantial role in defining semen's quality. Additionally, treatment with either a single (L, M, and S) or a combination of antioxidants enhances buck semen's motility and CASA properties (LM, LS, MS, and LMS).