Semi-arid Zone, Smallholder Farms

Figure

Typical Problems In This Area

1. Smaller farms in this zone can seldom manage to support many animals. Feed tends to always be in short supply and animals suffer constant nutritional stress.

2. Worm burdens often build up slowly and coupled with poor feeding lead to a long-term chronic condition.

3. Trichostrongylus, Haemonchus and Oesophagostomum can all be present and contribute to a generalised parasitic gastroenteritis.

4. During the dry seasons invading larvae may enter a period of delayed development in the animal (Inhibited worms).

Features Of The Area That Can Help In Control

1. Transmission is seasonal and a significant portion of the year is too dry for worm larvae to survive on pasture.

2. When inhibited worms are present, drug treatments can be efficiently targeted at these.

Control Methods That May Be Useful

· Frequent observation of individual animals and treating only clinical cases.

· Since rates of infection are seasonal, treatments can be targeted at times of year when there are peaks of infection.

· Since periods of poor grazing and nutritional stress are seasonal, treatments can be timed to alleviate chronic infections.

· At certain times of year a large part of the overall worm population is present as inhibited larvae. By correctly applying an effective drug at this time, infection rates can be reduced for the ensuing dry season.

· Keeping local breeds of animals rather than exotics can lead to higher production at lower treatment costs (Genetic Resistance).