Differences in susceptibility to trypanosome infection between Nkedi Zebu and Ankole cattle, under field conditions in Uganda.

A cross-sectional study was conducted in tsetse-infested areas of Soroti district in Uganda, with the aim of assessing the response of the Nkedi Zebu and Ankole breeds of cattle to trypanosome infection. Overall, 1215 Nkedi Zebu and 260 Ankole cattle kept under similar levels of tsetse challenge were examined for trypanosome infection, using the Buffy-coat technique and haematocrit centrifugation, and had their packed-cell volumes (PCV) measured. As expected, the infected cattle, whether of the Nkedi Zebu (26.7% v. 29.6%; P < 0.05) or Ankole breeds (24.9% v. 29.1%; P < 0.05), had significantly lower mean PCV than the uninfected. In the Nkedi Zebu cattle, the prevalence of trypanosome infection was lower (7.9% v. 10.8%; P > 0.05) and the overall mean PCV was significantly higher (29.4% v. 28.7%; P < 0.05) than in the Ankole. Compared with the Ankole, Nkedi Zebu cattle appear to be less susceptible to (detectable) trypanosome infection and to the trypanosome-attributable lowering of their PCV.