Summary Twenty bull semen samples were used to determine the effects of incubation temperature and length of incubation period on fructolysis. Split ejaculates were incubated at 27, 37, and 47° C. and fructose utilizations were determined at 60, 120, and 180min. Increase in temperature of incubation resulted in increased utilization, but had no effect on the fructolysis coefficient (Kv). For every 1° C. increase in incubation temperature, there was a 4.22% increase in fructose utilization and a 3.84% increase in maximum fructose utilization (MFU). The role of fructose as a rate-limiting factor was suggested by its effect on the 2nd- and 3rd-hr. fructose utilizations at 47° C. The routine addition of fructose to all incubated semen samples was suggested, to prevent fructose concentration from becoming a rate-limiting factor.