Recognizing the value of trypanotolerance

Tsetse flies, the main vectors of trynanosomiasis, infest some 11 million km3 of Africa, about 37% of the continent. The only cattle that can thrive and produce in these areas are the trypanotolerant breeds such as the N'Dama, which at present account for only about 6% of Africa's cattle. The ability to limit parasitaemia (the presence of trypanosome parasites in the blood), and the ability to limit the degree of anaemia are two major elements of trypanotolerance. Studies carried out in Zaire and Gabon under the African Trypanotolerant Network found these abilities to be an inherited trait and more heritable than growth rate. Therefore breeders should consider this worthwhile selecting for. The findings offer the possibility of carrying out selection tests for trypanotolerance on young animals and for implementing practical breeding programmes with N'Dama cattle. In the past N'Dama have not been considered to be worth much attention as a breed. However, now it is increasingly accepted that introducing N'Dama cattle into tsetse-infested areas, or increasing the number already present, may be a major practical sustainable way to increase livestock production and develop mixed farming in those areas. Dr Guy d'leteren, ILCA PO Box 46847, Nairobi, KENYATsetse flies, the main vectors of trynanosomiasis, infest some 11 million km3 of Africa, about 37% of the continent. The only cattle that can thrive and produce in these areas are the trypanotolerant breeds such as the N'Dama, which at present..