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OJVRTM
Online Journal of Veterinary Research©
Volume 13 (1):94-105, 2009. Redacted 2017.
Doayo (Namchi) Bos taurus cattle with low zebu attributes are trypanotolerant under natural vector challenge
Achukwi MD1,
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.
Achukwi MD, Ibeagha-Awemu EM, Musongong GA, Erhardt G, Doayo (Namchi) Bos taurus cattle with low zebu
attributes are trypanotolerant under natural vector
challenge, Onl 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)
weaners and 22 White Fulani (Bos indicus) weaners were exposed for one year to primary
trypanosome infections by natural vector 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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