Resistance of indigenous African cattle to the tick Amblyomma hebraeum.

Field collections of Amblyomma hebraeum Koch adults from six breeds of cattle were conducted on two farms in the Northern Transvaal. The density of A. hebraeum adults was highest on Simmentaler cows, followed by Santa gertrudis, Africaner, Bonsmara, Brahman and Nguni. Indigenous breeds, namely Nguni, Bonsmara and Africaner, have the highest level of resistance to A. hebraeum. The relationship between tick abundance and the high level of resistance found in the indigenous breeds is discussed.