Impact of natural infestation of Amblyomma variegatum on the liveweight gain of male Gudali cattle in Adamawa (Cameroon).

The effect of natural tick infestation on the liveweight gain (LWG) of male Gudali zebu cattle was studied throughout a year by comparing the performances of two herds, one of which was submitted to weekly acaricidal treatment and the other was left untreated against ticks. Six species of ticks were identified on the untreated animals: Amblyomma variegatum, Boophilus decoloratus, Rhipicephalus lunulatus, Rhipicephalus turanicus, Hyalomma nitidum and Hyalomma marginatum rufipes. Most of the losses observed in the untreated herd during the rainy season were due to A. variegatum, and the loss in LWG was estimated to be 55-76 g per engorged female A. variegatum. The infestation also leads to wounds and to lesions of dermatophilosis. There was an interval between the peak infestation by A. variegatum and the appearance of weight loss owing to them. The control of ticks on the Gudali zebu in Adamawa, during the months of high infestation by A. variegatum adults, is economically profitable. On the other hand, the performances of the two herds during the dry season were similar, showing that infestation by larvae and nymphs of A. variegatum has no impact on the zebu LWG, and that tick control during that period is not profitable.