Effects of Trypanosoma vivax and Trypanosoma congolense infections on the reaction time and semen characteristics of Zebu (Bunaji) x Friesian crossbred bulls

摘要

The effect of trypanosomosis on reaction time and semen characteristics of 12 Zebu (Bunaji) x Friesian crossbred bulls aged between 3 and 5 years was studied for a duration of 12 weeks. Four of the bulls were infected with Trypanosoma vivax, another four with Trypanosoma congolense and the remaining four bulls served as controls. Rectal temperatures and haematological parameters were monitored twice weekly. The pre-infection mean value of the rectal temperature was 38.3 degreesC, and this rose to a mean of between 40.5 and 41.1 degreesC in the infected animals. Concurrently, the infected animals exhibited signs of anaemia shown by pale mucous membranes and decreased packed cell volume (PCV), weight loss, lethargy, weakness and dullness.