Abstract: Neuraminidase activity was determined during experimental Trypanosoma evansi infection in Savannah Brown bucks. There was significant (p<0.05) increase in the activity of sialidase on day 7, 9, 21, 23, 27, 33 and 37 post-infection. Increase in sialidase activity coincided with gradual decline in mean erythrocyte surface sialic acid concentrations occuring 5 days post-infection. There were significant difference (p<0.05) in mean erythrocyte surface sialic acid between the infected and control groups on day 5 and between days 17 to 27 post-infection. A significant (p<0.05) increase in free serum sialic acid concentrations was observed on days 15, 17 and 27 when compared to the control group. All infected bucks developed trypanosomosis, with significant decreases in mean packed cell volume to as low as 19.50±2.12% occurring at day 33 post-infection which was significantly lower than the control value of 26.75±0.96. Mean haemoglobin concentrations also declined in the infected bucks with marked drop of 6.50±0.70 g dL-1 on day 33 post-infection and was significantly different (p<0.05) from the uninfected (control) group (8.53±0.46 g dL-1). The anaemia caused during infection may be attributable to the activities of the circulating trypanosomes, which produce sialidase (neuraminidase) that resulted in the cleaving off erythrocyte surface sialic acid, rendering such red blood cells more prone to phagocytosis in the reticuloendothelial system.