Animal trypanosomosis cause major livestock losses in Africa. Abnormal haematology and biochemical parameters in infected animals were reported, however the potential relationship of these two parameters with tolerance or susceptibility to the disease remains unclear. The present study aimed to monitor the haematological and biochemical parameters and to identify the biological variability associated with tolerant versus susceptible phenotypes. For this purpose, 7 N'Damas, 9 Fulani Zebus and 8 crossbreds (Fulani Zebu X European taurine), aged between 2-3 years, were infected intradermally with Trypanosoma congolense IL1180. Blood samples were collected on each cow prior and during infection for parasitological analysis and haematology and biochemical parameters assessment using respectively KHEMA4® and KBIO5® analysers (Kitvia). As expected, N'Damas showed the best anaemia control indicators compared to Fulani Zebus and crossbreds, which were sometimes anaemic. Prior infection, no significant difference in biological variables was observed between the breeds. However, after five months of infection a significant difference (p<0.05) in leukocyte counts and lymphocytes were recorded, with higher leukocytosis and lymphocytosis for N'Damas and intermediate values for crossbreds and Fulani Zebus. For biochemical variables such as levels of cholesterol, urea, albumin, alkaline phosphatase and glucose, values were higher in Fulani Zebus and crossbreds than N'Damas. However, globulin, alamine-amino-transferase, amylase, creatinine, ¿-GT and total proteins levels were higher in N'Damas than Zebus and crossbreds. Our study revealed major changes in haematology and biochemical variables associated with disease development. The role of each variable and how it may interact was therefore discussed in the context of trypanotolerance.