Talking to any beef or sheep farmer, one disease that frustrates them is coccidiosis.

It is caused by a small protozoan parasite of the eimeria species, which usually takes 15 to 22 days between ingestion and clinical signs, meaning it is often only suspected as a cause of disease in animals over 18 days.

The pre-patent period (the time between infection of the animal and the first appearance of oocysts in faeces) can be about 21 days for E. bovis, while it is shorter for E. alabamensis (eight to 12 days).

The cow or ewe is often the source of the initial infection, but infected animals can spread thousands of eggs in their dung. The infected calf or lamb is the main source of disease spread.

It typically affects lambs and calves between four and 10 weeks of age. They can develop immunity but require low exposure over time to do this.

The symptoms can be mild weight loss and being tucked up, as well as more severe symptoms such as diarrhoea and straining. Diarrhoea can be black with blood and mucus in it.

Oocysts, when passed in dung, can be resistant to disinfectants and survive for months in the environment

Lambs and calves with persistent straining can prolapse their rectums.

With young lambs at pasture, it can often be mixed up with nemadtodirus and in young calves, salmonella or other infectious scour-causing agents.

When other stressors are involved, or when the immune system is compromised, you will see very severe coccidiosis outbreaks.

Oocysts, when passed in dung, can be resistant to disinfectants and survive for months in the environment. Infected calves produce millions of oocysts in their dung.

Birds are often blamed for spreading coccidiosis but, in reality, are extremely low-risk. The main source of infection are animals infected, either lambs or calves.

We can get a diagnosis by dung-sampling and it is useful to get a species diagnosis of coccidia. Not many labs do this, so talk to your vet about the value of getting a species of coccidiosis diagnosis.

Treatment

Treatments include diclazuril and toltuzuril products. Lambs can often be given pain relief and calves with severe straining are given epidurals by a vet.

While sulfadimidine powders have been used in treatments, no conclusive evidence exists on how useful they are.

There is also an in-feed medication called decoquinates that can be fed through meal. This may delay immunity and any animals finished this in-feed medication must be moved to clean pastures.

Changes of diet, stress or adverse weather can all aid in the severity of disease shown in coccidiosis.

What can you do to reduce the risk?

  • Focusing on hygiene indoors and having plenty of fresh, clean bedding reduces the risk of buildup of these infective oocysts.
  • Stocking densities and space are important indoors to reduce the spread of disease.
  • Look for stressors in the calves’ environment and reduce them. Once one animal is infected, group treatment may need to be considered.
  • Older animals with no symptoms are a big risk when mixed with younger animals.
  • Hygiene in lambing and calving pens is essential.
  • If using the same pastures for turnout of calves and lambs each year, the use of preventive doses of diclazuril or toltuzuril are needed. Timing of doses may also be important with a general rule that calves four weeks and older get a dose two weeks after turnout. With lambs that have been out for a while, a dose should be given at four to five weeks.This varies across farms, but if repeat dosing is required, then check the product used, the amount given and the risk of the pasture.
  • Where lambs are being creep-fed outdoors, move feeders regularly and use lime around them. Leaking water troughs and muddy areas pose a greater risk for the buildup of oocysts.
  • Disinfect pens between groups and use an approved disinfectant. Clean out all dung and use a foaming agent to increase contact time for the disinfectant.
  • Where there are issues every year, look at breaking the cycle by providing a clean pasture for turnout of calves and lambs. E. alabamensis has been reported to cause enteritis in first-season grazing calves in the first week following turnout and also later in the grazing season. When calves that have symptoms are treated, they need to be moved. Ideally, they should be moved to clean pastures.
  • Sick calves require supportive treatment and fluids and veterinary advice should be sought for any extra treatments. Where calves or lambs are introduced into risk pastures, treatment must be considered to reduce the burdens.
  • Diclazuril and Toltrazuril are oral medications used for treatments and when timed correctly, act as preventatives. There is also an in-feed medication, decoquinate. There are a number of these products under different brand names available, so consult your vet on the best option for you.
  • Controlling coccidiosis can be quite farm-specific. We need to focus on management and dosing. It is worth reviewing these factors, especially where coccidiosis is a problem every year.