Coccidia are protozoan parasites that develop in the intestinal tract of cattle, sheep and goats. Mostly affects young animals before their lifetime immunity develops. Coccidiosis is when the disease manifests as a result of a coccidia infection.
Coccidia Life Cycle
Coccidia produce oocysts which exit livestock through dung. Once on the pasture, they sporulate after 1-2 days (longer when the weather is cool), and then become infective to grazing livestock. After this, it takes about 16 days for the life cycle to progress to a stage that affects the animal. Hence, it is not usually diagnosed in stock less than 4 weeks of age.
Risk Factors for Coccidiosis
- Temperate climates with moderate temperatures and consistent rainfall.
- High stocking rates
- Stressed stock (i.e., from cold, movement, weaning, lambing, inadequate nutrition)
- Reduced immunity (worm burdens, overcrowding, inadequate colostrum intake, selenium and/or copper deficiency)
- Younger animals
- Large amounts of coccidia in the environment (mud, stock camps, around troughs, infected feed)
Signs of Coccidiosis
- Diarrhoea (can be bloody)
- Straining and tail swishing (will cause a butterfly shape of dags/stain)*
- Weight loss and poor growth
- “Pot-bellied”
- Dehydration and weakness
- Reduced feed intake
- Severe cases can result in death.
Diagnosing Coccidiosis
Coccidia oocyst counts can be conducted (generally in conjunction with worm egg counts) however, high counts do not necessarily correlate with disease severity as the stock develop their own immunity.
Coccidosis can also be diagnosed from a post mortem (‘nodules’ on small intestine, see picture below).
It’s important to note that without appropriate testing for a definitive Coccidiosis diagnosis, it is usually only ever a differential diagnosis. This means there are other diseases that may be presenting with similar signs (e.g., worms, salmonella, pestivirus in calves, campylobacter scours in lambs and giardia). These other issues should be investigated and treated first before resorting to anticoccidial medications as a treatment option.
Preventing Coccidiosis
- Rotational grazing which prevents livestock making ‘camp areas’ which in turn will reduce environmental coccidia load.
- Provide clean water (prevent muddy build up around troughs)
- Move hay and grain feeding sites around the paddock (don’t use the same spot all the time)
- Reduce weaning stress as much as possible (good feed, effective worm drench, imprint feeding pre-weaning)
- Quarantine new animals
Generally, healthy and productive livestock are at lower risk of being adversely affected by coccidia, as they develop their own immunity. So the best way to treat and prevent this parasite is by good management of other scour worms, keeping macronutrients and trace minerals in balance, and getting livestock nutrition right. If these factors are managed well, then coccidiosis is seldom a problem in grazing lambs and/or calves.
References
Wormboss Webinar – Keeping Coccidiosis at Bay, Alison Gunn (Herd Solutions)
Coccidia and Cryptosporidium | Paraboss