The impact of pure infestations of Rhipicephalus appendiculatus and Amblyomma hebraeum on the productivity of cattle and implications for tick control strategies in Africa.

This paper reviews studies carried out by an FAO project in Zimbabwe, on the effects of the ticks Rhipicephalus appendiculatus and Amblyomma hebraeum on the productivity of cattle. Larvae and nymphs of the two species had no detectable effect on liveweight gain (LWG). The losses in LWG caused by each adult female that completed feeding were approximately 4 g for R. appendiculatus and 10 g for A. hebraeum. Losses in milk production caused by both species amounted to approximately 7 g for every female that engorged. The loss in productivity per engorged female, known as the damage coefficient, can be used in simulation models to estimate the value of production losses caused by the ticks and the economic benefits of control strategies.