The innate (genetically based) tolerance
to the disease (the so-called trypanotolerance) is a phenomenon
present in some African cattle and small ruminant breeds.
Trypanotolerance is defined as the ability to survive and
to be productive in tsetse infested areas without the aid
of Trypanosomosis treatment while other breeds succumb to
the disease.
Trypanotolerance is usually attributed to the African Bos
taurus taurus breeds of cattle, particularly the N’Dama
and the West African Shorthorn, present mainly in West and
Central regions of Africa. Farming of disease-tolerant genotypes
is one of the options for limiting the disease impact on animal
health and production that has yet to realize its full potential.
The exploitation of the so-called trypanotolerant breeds has
been practiced for centuries as major, if not the only, option
to sustain livestock production in 19 countries in the humid
parts of West and Central Africa. However, trypanotolerance
is a feature of only a third of the cattle in tsetse infested
Africa, and of no more than 10% (or 15 million) of the cattle
population south of the Sahara.
Limitation to fully exploit these breeds can be attributed
largely to the belief that they are not productive because
of their smaller size compared with most zebu types (Bos taurus
indicus), and to the view that their trypanotolerance is effective
only against local trypanosome populations. These views are
still debated. It is generally admitted, however, that the
trypanotolerant feature constitutes a valid option for animal
production in tsetse infested areas and it is an element of
the integrated pest management approach.
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