Comparative haematology of quantitative PCR negative trypanotolerant and trypanosusceptible cattle in Nigeria

Haematologic studies are helpful in the selection of genetically resistant animals. African animal trypanosomiasis (AAT) is an important protozoan parasitic disease associated with haematopathologies. There is dearth of information on the haematologic differences between trypanosusceptible (TS) and trypanotolerant (TT) cattle in the absence of AAT. Fifty apparently healthy adult cattle comprising 13 Muturu, 11 N’Dama (TT), and 26 White Fulani (TS) were sampled. Whole blood was collected for complete blood count (CBC), blood cell morphology, microscopic screening, and quantitative polymerase chain reaction (qPCR) assay for trypanosome. Red blood cells (RBCs) and white blood cells (WBCs) with unusual morphologies were quantified as number per 100 RBCs and WBCs, respectively. Trypanotolerant (TT) cattle had significantly higher packed cell volume (PCV) (34.48 ± 1.3 vs 31.08 ± 1.1%), haemoglobin concentration (HB) (12.901 ± 0.4 vs 10.2 ± 0.4 g/dL), and RBC count (6.2 ± 0.3 vs 4.8 ± 0.2 × 10 6 /µL), than TS cattle. Lymphocyte counts were significantly higher in TT (3.6 ± 0.2 × 10 3 /µL) than in the TS cattle (2.9 ± 0.2 × 10 3 /µL); however, TS had higher neutrophil counts than TT cattle. Abnormal RBCs, namely acuminocytes (16.61 ± 3.5 vs 0.74 ± 0.3), cigantocytes (6.65 ± 0.7 vs 0.96 ± 0.3), degmacytes (1.78 ± 0.5 vs 0.48 ± 0.2), activated monocytes (5.44 ± 0.9 vs 1.91 ± 0.6), reactive lymphocytes (4.22 ± 0.9 vs 1 ± 0.5), and bi-nucleated lymphocytes (1.52 ± 0.4 vs 0.09 ± 0.1) were significantly higher in TT cattle. These findings may be indicative of increased haematopoiesis and a more active immunity in uninfected TT breeds.