Haemonchotolerance in West African Dwarf goats: contribution to sustainable, anthelmintics-free helminth control in traditionally managed Nigerian dwarf goats.
Bottom Line: Here, we summarise the history of this breed and explain its economic importance in rural West Africa.If haemonchotolerance can be shown to be genetically controlled, it should be possible to exploit the underlying genes to improve GIN resistance among productive fibre and milk producing breeds of goats, most of which are highly susceptible to nematode infections.Either introgression of resistance alleles into susceptible breeds by conventional breeding, or transgenesis could be used to develop novel parasite-resistant, but highly productive breeds, or to improve the resistance of existing breeds, benefitting the local West African rural economy as well as global caprine livestock agriculture.
Affiliation: Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Nigeria.Show MeSH
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Mentions: The fourth characteristic of haemonchotolerance is the ability of haemonchosis to co-exist in the same host with trypanosomosis caused by T. brucei without significant interaction between them . Concurrent infections with these two highly virulent parasitic diseases of ruminants in sub-Saharan Africa are characterised by marked increases in FEC and Wb, diminished H. contortus-specific serum antibody responses and far-reaching pathophysiological consequences, in N’dama cattle , as well as in dwarf sheep and goats [24, 29] in the Gambia. This is believed to be as a result of trypanosome-elicited immunosuppression, resulting in down-regulation of host resistance to concurrent nematode infections. Surprisingly, these specific effects do not occur in Nigerian WAD goats, except for a small but significant increase in the Wb of a minority of weak responder (HFEC) phenotype of goat (, Fig. 8). Serum H. contortus-specific IgG levels were unaffected in both HFEC and LFEC phenotypes (Fig. 9). This is unusual and suggests that trypanotolerance, which is strong in Nigerian WAD goats , and haemonchotolerance co-exist in nature in this goat genotype. Supportive evidence for this hypothesis was provided by our subsequent field study in a savannah goat population in northern Nigeria . We do not know of any other breed or species of livestock, including dwarf goats, in trypanosome-endemic zones of sub-Saharan Africa, which is known to possess and express both of these important survival traits of parasite resistance in concurrent infections.Figure 8.
Affiliation: Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Nigeria.