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OJVRTM
Online
Journal of Veterinary Research©
Volume 13 (1):94-105, 2009
Doayo (Namchi) Bos taurus cattle with low zebu attributes are trypanotolerant
under natural vector challenge
Achukwi MD, Ibeagha-Awemu
EM2,3, Musongong
GA1, Erhardt G2
1Institute of
Agricultural Research for Development (IRAD), Wakwa Regional
Centre, Veterinary Research Laboratory. P.O. Box 65 Ngaoundere Cameroon.2Institute
of Animal Breeding and Genetics, Justus-Liebig-University
Ludwigstrasse 21b, D-35390 Giessen, Germany
3Department of Animal Science, McGill
University, 21,111 Lakeshore Road, Ste Anne De Bellevue, QC
H9X 3V9 Canada.
ABSTRACT
Achukwi MD, Ibeagha-Awemu
EM, Musongong GA, Erhardt G, Doayo (Namchi) Bos taurus cattle with low zebu
attributes are trypanotolerant under natural vector
challenge, Online J Vet Res, 13 (1):94-105, 2009. Trypanosomosis remains one of the major constraints
limiting animal production and productivity in sub-Saharan Africa.
Genetic resistance to trypanosomosis in some indigenous cattle breeds offers
another option to be included in the approaches currently used in the fight
against the disease. Fifteen Doayo or Namchi (Bos taurus)
and 22 White Fulani (Bos indicus) weaners were exposed
for one year to primary trypanosome infections by natural challenge. Seven microsatellite markers with known zebu specific alleles
were used to detect and eliminate highly-introgressed
individuals of the Doayo breed and White Fulani X Doayo crosses. The packed cell volume (PCV) and trypanosome
parasitaemia of the animals were measured every other
week. All animals became infected with trypanosomes during the study period. The Doayo cattle
down regulated parasitaemia significantly
(P<0.005) more than the White Fulani. In both breeds, the PCV declined with increasing time
but the pathological effects of trypanosome infection on PCV were significantly
higher (P<0.01) in the White Fulani than the Doayo cattle. This
clear superiority in resisting PCV drop and excessive rise in parasitaemia over time shown by the Doayo
cattle, in spite of the higher incidence of trypanosomosis
in the Doayo, implies that the Doayo
cattle are trypanotolerant under natural trypanosomosis infection. The proportion of zebu specific alleles could be a
pointer to the extent of the dilution or contamination of the taurine genome and indicates, to a large extent, the
potential susceptibility of the individual to trypanosomosis.
The dwindled
population size of the Doayo cattle and crossbreeding
with White Fulani remain major causes for concern in the exploitation of this
valuable genetic material for the control of animal trypanosomosis
in the region.
Key words: Doayo, zebu specific alleles, introgression, trypanosomosis, haematocrit, trypanotolerance
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