Major differences in the dynamics of haematological and biochemical variables between trypanotolerant and susceptible cattle during Trypanosoma congolense infection

Background Animal African Trypanosomosis, caused by protozoan blood parasites mainly transmitted by Glossina , is a threat to livestock health in Africa. Whilst African zebu and European taurine suffer from trypanosomosis, West African taurine, such as N’Dama, exhibit trypanotolerance and remain productive in enzootic areas. Trypanosomosis affects haematological and biochemical variables in cattle. However, joint characterization of the temporal dynamics of these variables during trypanosomosis in tolerant or susceptible cattle had yet to be carried out. The purpose of this study was to show the potential association of various profiles of haematological and biochemical variables with trypanotolerance. Three cattle breeds comprising N’Dama, West African Fulani zebu, and crossbred cattle (West African zebu x European taurine) were infected with Trypanosoma congolense and were monitored for six months post-infection. Results As expected, N’Dama controlled anaemia and parasitaemia better than Fulani zebu and crossbred cattle. Lymphocytosis and monocytosis were observed in N’Dama, while lymphocyte and monocyte counts remained unchanged in Fulani zebu and crossbred cattle. Granulocyte counts decreased in Fulani zebu and crossbred cattle, but remained stable in N’Dama. Cholesterol and glucose concentrations decreased significantly after inoculation with trypanosomes, but relative variations were observed depending on the breed, with rapid recovery of cholesterol levels in N’Dama. The relative variation in haematological variables was positively correlated with those of cholesterol and glucose, and negatively correlated with parasitaemia. Parasitaemia was also negatively correlated with variations in cholesterol and glucose levels. Conclusion This study highlighted some striking differences in the evolution of white blood cells and certain biochemical traits related to trypanotolerance.