Coccidiosis and its control
J.D. Wineter and J.D. Williams BVSc. Department of Agriculture, Agricultural Research Centre, Wollongbar, NSW. 2480
Coccidiosis is a condition in sheep, goats and calves caused by presence of microscopic parasites (Eimeria spp) in the small intestine.
Young goats tend to be more susceptable to coccidiosis infections than mature goats and may die very quickly.
It is therefore, important to understand the essential features of this disease, to recognise its presence and institute control measures to minimise outbreaks.
Coccidiosis is most common in young goats, especially during stressful periods. These tend to be at approximately six weeks of age and at weaning.
Goats appear to develop an immunity to coccidiosis with age; however, this immunity can breakdown under stress. Worm burdens often combine with coccidial infections to increase the rapidity and severity of illness.
Goats become infected by consuming coccidial eggs (called oocysts) while grazing. Does shed very large numbers of oocysts in dung after kidding. Close confinement of does and kids in warm damp conditions favour spread and heavy infection.
Coccidial parasites develop through a number of stages in the small intestine, destroying the sensitive lining. Bleeding into the gut is also possible, producing signs of anaemia such as pale membranes in the eyes and mouth, pale skin and weakness.
Damage to the gut wall is associated with strong movement of the intestine and colic pain. The goats may scour profusely. If bleeding is heavy, the scour is foul smelling, with a dark, tarry appearance. In acute cases, animals may die before scouring is observed.
Often when coccidiosis is associated with worm burdens and the goats are drenched, scouring will continue due to the presence of coccidiosis. The continued scouring may be incorrectly interpreted as drench resistance or drench ineffectiveness.
Animals scouring with coccidiosis will be shedding the oocysts in their dung. These can be recognised if dung samples are given to a veterinarian for microscopic examination.
Awareness of the problem is probably the best start to control. Most adult goats have some coccidia present in their gut and some oocysts are always being produced. These are normally at low levels. However, areas regularly experiencing outbreaks can institute control measures as follows:
- Avoid subjecting goats (especially kids) to stressful situations or damp confined areas.
- Feed does prior to and immediately after kidding with a coccidiostat (e.g. monensin*). Coccidiostats are available either as a feed additive or can be put in drinking water. This will reduce the contamination of pastures and the doe's udder with oocysts after kidding, be reducing the numbers that are naturally being produced by the does.
- At weaning, feed kids a coccidiostat, in a feed supplement to lower the levels of infection.
- Inject all kids with three consecutive daily doses of sulphamezathine* at approximately six weeks of age. This will eliminate the coccidial burdens which have developed. Such treatments may not be necessary if other control measures listed above are adopted. Conversely these treatments are essential to control outbreaks of the disease involving deaths and sick scouring animals.
- Inject early weaned kids with sulphamezathine* (as in 4). Again it is preferable to avoid these treatments if rendered unnecessary by other control measures; treatment appears to be painful for a short time after injection.
- If animals continue to scour after drenching for worms, consult a veterinarian for an accurate diagnosis of the problem. Examination of dung samples will differentiate between worm resistance, drench inaffectiveness and coccidiosis.
* For use of these products, consult your State Department of Agriculture for names of registered products and dose rates.
© 1985 A.C.G.A.