Succinate dehydrogenase (SDH), lactate dehydrogenase (LDH), glutamateoxaloacetate transaminase (GOT), and acid and alkaline phosphatase are present in ram, bull, dog, rabbit, and human semen but the concentrations differ from one species to another. Amylase is found in the semen of all these species except the ram, and glucose�6-phosphate dehydrogenase (GDH) in all except the bull.