11 April 1997

Coccidiosis on rise

INCIDENCE of coccidiosis in lambs at pasture is rising as more sheep are stocked at higher densities.

Liverpool-based vet Agnes Winter says coccidiosis is often considered a disease of indoor lambs but sheep at pasture are vulnerable, too.

"Risk of the disease increases when the same paddock is used in successive years to turn ewes and lambs on to. And the problem is compounded where grass is heavily stocked and when lambs of different ages are mixed," says Dr Winter.

Coccidiosis occurs when lambs ingest lots of coccidial oocysts, which are excreted on to pasture by sheep of all ages. The coccidia are then consumed by the younger lambs as they are turned out.

Symptoms include scour which is often bloody and in some cases can cause sudden death.

Coccidiostats can be fed in creep feed and when coccidiosis is a particular problem treatments with a sulphonamide should be given to lambs at three and six weeks old.

"Ideally, ewes and lambs should be turned on to clean pasture and sheep should not be stocked too heavily. If this is not possible it may help to move feed troughs every few days because there will be more coccidia where activity of sheep and lambs is concentrated." &#42