An evaluation was conducted on the effects of melatonin in semen extender on semen quality measures in Teressa bucks. For the investigation, a total of twenty-five semen samples from six bucks were chosen. Gr II, III, and IV spermatozoa were incubated in 10 µg, 20 µg, and 40 µg of melatonin/150 × 106 spermatozoa, respectively. For up to 96 hours, liquid-stored semen samples were examined for motility, viability, total sperm abnormality, plasma membrane, acrosomal and nuclear integrities, intracellular enzymes (aspartate aminotransferase; AST, alanine aminotransferase; ALT, and lactate dehydrogenase; LDH), cholesterol efflux, seminal total antioxidant capacity (TAC), and malondialdehyde (MDA) in relation to the control group (Gr I). The findings showed that, at different times during liquid storage, sperm treated with 20 µg of melatonin had significantly (P<0.05) lower total sperm abnormalities, AST, ALT, LDH, MDA, and cholesterol efflux and significantly (P<0.05) higher motility, viability, plasma membrane, acrosomal and nuclear integrities, and TAC. Antioxidants and semen quality measures were trending upward, whereas total sperm abnormalities, MDA, intracellular enzyme leakage, and cholesterol efflux were trending downward from Gr I to Gr III and subsequently in the opposite direction from Gr III to Gr IV throughout various liquid storage hours. Therefore, 20 µg of melatonin was an appropriate dosage for Teressa goat liquid semen preservation.