Trypanosome infection in indigenous cattle breeds and their crossbred genotypes: Effect on haematological variables and assessment of trypanotolerance

Abstract

Control of African animal trypanosomiasis through vector eradication and chemotherapy has become

unsustainable. Sustainable control through exploitation of trypanotolerance genetics is advocated. The

study evaluated the prevalence and effects of natural trypanosomes infection on haematological

indices to assess trypanotolerance in purebred, and crossbred/composite cattle genotypes in a humid

tropical environment. Haematological indices were evaluated following standard laboratory

procedures while parasitological diagnosis was by blood microscopy. Parasitaemia was expressed as

number of parasites/ml. Prevalence of parasitaemia was 3.3 % but 21.4 % among anaemic cattle while

anaemia was 15.4 % in the herd. Cattle breed/genotype was not significantly associated with anaemia

or parasitaemia but anaemia was significantly associated with parasitaemia (χ2: 9.500, p < 0.002).

Anaemic cattle had lower (p < 0.05) RBC, PCV, and RBCOF (4.46 ± 0.16 x 106/ml, 21.92 ± 0.30, and

9.18 ± 1.82 %, respectively) compared to non-anaemic cattle (5.28 ± 0.08 x 106/ml, 28.63 ± 0.33, and

18.93 ± 0.96 %, respectively). Parasitaemic animals had lower PCV (20.13 ± 0.49 %) but higher

RBCOF (32.54 ± 2.94 %) compared to aparasitaemic counterparts (28.14 ± 0.34, and 16.88 ± 0.85 %,

respectively). Parasitaemic anaemic cattle had lower PCV but higher RBC, Hb, and RBCOF

compared to aparasitaemic counterparts. Lymphocyte was higher (58.33 ± 1.67 %) while eosinophil

was lower (9.33 ± 0.33 %) in parasitaemic anaemic cattle compared to aparasitaemic group (47.55 ±

1.93, and 14.09 ± 0.61 %, respectively). N’Dama and crossbred/composite cattle were aparasitaemic

and less anaemic than White Fulani cattle indicating stronger trypanotolerance.