Central Kenya High Altitude Zone

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Typical Problems In This Area

1. High grazing pressure means that transmission rates can be high and there are few opportunities to control worms by grazing management.

2. Because of the relatively cool conditions at this altitude, pasture can remain infective for long periods after it has been last grazed.

3. There are many liver fluke transmission sites.

4. Due to the uneven distribution of rainfall during the year, there are times when grazing is in short supply and animals suffer from nutritional stress.

5. The presence of both Haemonchus and liver fluke can lead to a chronic syndrome (which can become worse during periods of poor feeding).

Features Of The Area That Can Help In Control

1. Worm challenge rates vary with the season and periods of peak infection occur during or shortly after the rains.

2. Larvae on pasture survive best when the grass is still green. During periods when grass growth has stopped, larvae rapidly begin to die.

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.

· Mixed use of broad and narrow spectrum drugs can help control Haemonchus and liver fluke.

· Medicated feed blocks can be made with locally available ingredients and provided to the animals overnight in the boma.

· Specific treatments to control liver fluke can be applied at times of year when these are most likely to be effective.