The effect of lactose-in-saline infusion on packed cell volume variation during trypanosoma vivax – induced anaemia of cattle

The effect of intravenous infusion of a solution of lactose-in-normal saline on the course of Trypanosoma vivax induced anaemia in Zebu yearlings was investigated. The animals were infected with 11 x 106 trypanosomes by jugular venipuncture and lactose-in-normal saline infusion started on day 6, post-infection (p.i). Three four-hourly doses of 0.5 g lactose/kg body weight were administered to each infected yearling in the experimental group daily for five days, while the infected control yearlings received no lactose-infusion. The experiment was terminated on day 13, p.i. Parasitaemia in the lactoseinfusedyearlings was scorable throughout the duration of experiment while parasites could not be detected in the blood of the infected control yearlings between days 7 and 9, p.i. Serum free sialic acids(FSA) concentration was also consistently higher in the lactose-infused yearlings than in the lactosefree ones. In the before lactose infusion (BL) period the PCV of the lactose-infused group dropped at asignificantly (P < 0.05) faster rate than in the lactose-free one. In the DL (during lactose infusion) period, the rate and magnitude of decline in PCV was significantly lower in the lactose-infused yearlings than inthe lactose-free animals. When lactose infusion was stopped (AL) the rate and magnitude of PCV decline became greater in the lactose-infused yearlings than in the lactose-free ones. It was thusconcluded that lactose ameliorated anaemia, by inhibiting the sequestration of desialylated erythrocytes from the blood stream of T. vivax-infected yearlings. This manifested in the reducedmagnitude and rate of decrease in PCV in the lactose-infused infected yearlings.