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Coccidiosis causes scours in lambs, requires active management on the ranch

by Wyoming Livestock Roundup

Coccidiosis, a common cause of scours in lambs, is caused by coccidia. The single cell protozoa is neither a bacteria, virus or a roundworm. Many species of coccidia are present in the environment, some of which are highly infective.

Michael Neary of Perdue University says, “Strains of coccidia are animal specie-specific, and there is very limited crossover between sheep and goats.”

The protozoa is always present in the flock, and most adult animals carry coccidia in their small intestine.

The complicated life-style of coccidia is about 21 days in length.

Coccidia propagate in the small intestine, and the process damages the cells of the organ. Eggs are released via feces into the environment where they are spread to other animals.

Sign and symptoms

Bill McBeth, a Zoetis veterinarian, says, “Usually, the young animals that have not been exposed to low levels of the protozoa and have not developed immunity are impacted.”

Coccidiosis results in abdominal pain, diarrhea, rectal strains and general poor doing of livestock.

The Merck Veterinary Manual notes that signs of coccidiosis may also include dehydration, fever, weight loss, anemia, wool breaking or death.

“Reducing stress is key to the animal husbandry with coccidiosis,” McBeth says.


University of Maryland notes, “As with most other diseases, it is far better to prevent coccidiosis than to treat it. By the time clinical signs have been observed, much of the damage has already occurred.”

“Lambs one to six months old in lambing pens, intensive grazing areas and feedlots are at greatest risk as a result of shipping, ration change, crowding stress, severe weather and contamination of the environment with oocytes from ewes or other lambs,” says the Merck Veterinary Manual.

Sanitation is the first line of defense since the oocytes causing cocciosis are spread in feces.

Neary encourages producers to clean their barn, keep dry, adequate bedding and prevent contamination of feed and water.

University of Maryland also recommends that producers don’t mix different age groups of animals in a grazing rotation.

“Older animals, including older lambs and kids, serve as reservoirs of infection,” they comment.

Drug treatments

McBeth notes that cocciodiostats can also be utilized to treat coccidiosis before the animals are stressed. Some coccidiostats include laslaocid and decoquinate.

“They can be used before lambing or weaning,” he explains. “If lambs have been exposed to coccidiostats 28 days before they are weaned and sent down to the feeder in Colorado, it is helpful.”

  He also adds that some feedlots provide coccidiotstats on arrival at the feedlot, which are both good, long-term preventative medicines.

To treat coccidiosis, the only approved product is sulfaquinoxaline. The Food and Drug Administration does not approve most drugs for coccidiosis for use in sheep and goats.

Subclinical coccidiosis

“We don’t usually think about subclinical coccidiosis,” McBeth adds. “Subclinically, it is there all the time in younger animals, and that can impact productivity, depress feed consumption and appetite as well as weight gain.”

As a result, lambs don’t realize their genetic potential.

“It may also suppress the immune system, which leaves them susceptible to other diseases,” he says.

Saige Albert is managing editor of the Wyoming Livestock Roundup and can be reached at

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