Q.
How do I prevent and treat coccidiosis in my flock/herd?
A.
Coccidiosis is an opportunistic disease that causes diarrhea (scours) and ill thrift in lambs/kids, mostly 1 to 6 months of age. It is one of the most common diseases of young lambs/kids. It is caused by a protozoan parasite, Eimeria spp.
Coccidia are host-specific. Sheep/goats can't get coccidia from poultry or other animals. Even sheep and goats don't share the same species of coccidia. Some coccidia species are non-pathogenic (not harmful). Others are highly pathogenic. All sheep/goats are infected at some point in their lives. Most develop immunity at an early age; in fact, sooner than they develop immunity to parasitic worms.
Adult animals, especially sheep, are immune to coccidia; however, they serve as reservoirs of infection, especially during the periparturient period. Clinical disease occurs when the level of exposure overwhelms the animal's immune system (common). Coccidiosis should be suspected anytime young lambs/kids are experiencing digestive issues, especially if they are being raised under intensive conditions. Fecals are of limited value in diagnosing disease.
Outbreaks of coccidiosis are most commonly associated with sloppy conditions and poor management. They are more of a problem in closely confined animals than those that are pastured, though outbreaks can still occur on pasture, especially under intensive grazing situations. Transmission is the oral-fecal route. Sources of infection (contamination) include hay, grain, bedding, pasture, udders, teats, water troughs and feeders (especially creep feeders).
Affected lambs/kids show signs of general ill thrift: loss of weight and body condition, lethargy, weakness, anorexia, and dehyration. The most common sign of coccidiosis is diarrhea (scours), often foul-smelling, blood or mucous smeared, sometimes watery (severe). Lambs/kids may have a distended (pot) belly, experience abdominal pain, and struggle to defecate. Coccidia cause intestinal damage, affect nutrient absorption, and can cause permanent damage to the digestive tract. Severe infections can result in death.
Prevention
Prevention of coccidiosis starts with good sanitation and hygiene. Removal of soiled bedding is ideal, but not always practical. Mostly the bedding on top of the manure pack should be kept clean and dry. Pens should not be overstocked. Water sources and feed troughs need to be kept free from fecal matter. Beware of leaky waterers. The kinds of feeders used for creep feeding are very important. Open trough feeders are especially problematic.
While there is debate as to whether lambs/kids get any immunity to coccidia via colostrum, adequate intake of colostrum gets the lamb/kid off to a good start and helps to prevent opportunistic diseases. The same is true of good nutrition in general. Animals on a low plane of nutrition are always more susceptible to diseases than those being fed proper diets. It is important that there be adequate feeder space in the creep or feeding area. Young lambs/kids should not have to compete for feeder space. Lambs/kids of significantly different ages should not be mixed.
Outbreaks of coccidiosis are common after (early) weaning. So, it is important that weaning be as stress-free as possible. Weaned lambs/kids should be kept in familiar surroundings with their pen mates. They should be consuming the same diet after weaning as before. The higher their consumption of creep feed, the easier their transition will be. They should be handled and vaccinated (twice) for overeating disease prior to weaning. Avoid hauling newly weaned lambs/kids.
Coccidiostats can aid in the prevention of coccidiosis. There are several options. Lasalocid (Bovetec®) is approved for lambs. Monensin (Rumensin®) is approved for goats. Decoquinate (Deccox®) is approved for both species. Bovatec® and Rumensin® are antibiotic ionophores. They (especially Rumensin®) are toxic to equines. Deccox® is not an antibiotic. While coccidiostats have other benefits besides control of coccidia, they should not be fed year-round for concern of drug resistance.
Coccidiostats are typically put in feed, mineral, and/or milk replacer. They need to be introduced three to four weeks before the risk of clinical disease, at the beginning of the coccidia life cycle. Timing is very important. Coccidiostats do not treat coccidiosis. They help to prevent it. Their effectiveness depends on the animals consuming the required (labeled) amount of the drug. This is the challenging part, especially with nursing lambs/kids. Some animals consume more mineral that others. Some lambs/kids eat more creep feed that others. Forage consumption further reduces intake of the drug. This is why coccidiostats are only part of the strategy for controlling coccidia.
Some producers feed a coccidiostat to pregnant ewes/does. The idea is to reduce the level of contamination in the lambing/kidding area. Similar to parasitic worms, there is a periparturient rise in coccidia oocysts. Feeding a coccidiostat in late pregnancy may also help to prevent abortions caused by toxoplasma gondii, a leading cause of small ruminant abortions. This is an extra label use of coccidiostats, so a veterinarian should be consulted.
Treatment
Dewormers have no efficacy against protozoan parasites. In addition, the drugs used to treat coccidiosis are different from the ones that are used to prevent it. Treatment options include amprolium (Corid®) and sulfa antibiotics, e.g., Di-Methox®. There are no treatments FDA-approved for small ruminants. Extra label drug use is required. You need a valid veterinarian-client-patient relationship. While Corid® can be purchased over-the-counter, you must obtain sulfa antibiotics from a veterinarian, as the 2017 Veterinary Feed Directive transitioned water-soluble antibiotics to prescription.
When using Covid® and sulfa drugs to treat coccidiosis, you need to drench individual lambs/kids for five days. You can't rely on putting the drug in the water. Clinically-parasitized animals may not drink enough water. Some producers will put Corid® or sulfa drugs in the water for five days as a preventative, but these drugs are better as treatments.
Outside the US, there are other options for controlling coccidia. Totrazuril (BayCox®) and diclazuril (Vecoxan®) are licensed in Europe and other countries for the control of coccidia in lambs (and calves). Totrazuril is usually effective as a single treatment whereas diclazuril may require a second dose. Timing is very important. Totrazuril has a very long withdrawal period (48 days for lambs). There is no withdrawal period for diclazuril. Totrazuril can be obtained in the US, but it is approved to use in sheep/goats. Ponazuril is a metabolite of totrazuril. In the US, it is availabe as Marquis®, a drug for horses. Experimentally, a single dose of it was equally effective as a five day treament of Corid® (in kid goats).
More natural methods of coccidia control are being sought. There is evidence that sericea lespedeza (SL; Lespedeza cuneata), a warm season legume, may aid in the control of coccidiosis (due to the condensed tannins in it). Lambs/kids consuming SL diets have lower oocyst counts and less clinical signs than those consuming non-SL diets. Other natural options are being studied, e.g., oregano and other essential oils. BioWorma® is not effective against coccidia. Good hygiene, good nutrition, and good management are the best natural control options.
5/28/21
Additional reading
Coccidiosis: Sheep 201
Management of Coccidia - Best Management Practices (wormx.info)
Sericea lespedeza for natural control of coccidiosis (wormx.info)