By using a "leader and follower" system, the cleanest pasture
can be retained for the more susceptible animals and the more contaminated
pasture can be grazed by the most resistant stock. These latter animals may also
help clean the pasture of infectious larvae.
The "leaders" in the system are normally the younger animals and
the followers the older animals. The system can also utilise differences in
breed or species susceptibility, with small ruminants grazing ahead of cattle or
more resistant genotypes such as red maasai sheep grazing behind more