Controlling tsetse with insecticide-treated cattle

Do I need to treat all my cattle?

No you do not and, in fact, you should not do so for two reasons.

• First, most indigenous breeds of cattle have an innate resistance to tick-borne diseases which they acquire by being exposed to ticks when they are still calves (see review by Torr et al., 2002).
• Second, tsetse seem to feed preferentially on the older and larger cattle in a herd (Torr et al., 2001; Torr et al. 2007).

So by treating only the older and larger animals we not only allow cattle to develop resistance to tick-borne diseases but also apply the insecticide to the cattle that are more likely to be bitten by tsetse.

As a general rule, you should just treat half the herd, selecting the bigger animals.

References
Torr, S., Eisler, M., Coleman, P., Morton, J. & Machila, N. (2002). Integrated control of ticks and tsetse: A report for the DFID Advisory and Support services Commission (Project ZV0151; NRI code V0160). 150 pp.

Torr, S.J., Wilson, P.J., Schofield, S., Mangwiro, T.N.C., Akber, S. & White, B.N. (2001). Application of DNA markers to identify the individual-specific hosts of tsetse feeding on cattle. Medical and Veterinary Entomology 15, 78-86.

Torr, S.J., Prior, A., Wilson, P.J. & Schofield, S. (2007). Is there safety in numbers? The effect of cattle herding on biting risk from tsetse flies. Medical and Veterinary Entomology 15, 78-86.