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Coccidiosis — Practical Control And Treatment

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For every clinical case there are many subclinical cases affecting performance and this may carry on for the life of the animal.

Coccidiosis can be one of the most frustrating diseases to treat in young beef calves. If not caught early death losses can be as high as 20 per cent and many calves will have enough intestinal damage to make them poor doers for life. Coccidiois has a long life cycle and the oocyst (like an egg) is very resistant to the environment, making prevention more complicated.

Over the years prevention has been much improved because of very good coccidiostats which can be given to the cows ahead of calving or calves in the feedlot.

Coccidiosis is spread via the fecal-oral route and undergoes a 21-28-day cycle. During this cycle this protozoa multiply mainly in the large intestine, causing often-irreparable damage and scarring to the intestinal lining. This is why one of the first clinical signs can be a dark tarry diarrhea from bleeding into the intestine. This blood is partly digested before it is expelled. In severe cases straining from the irritation can even result in prolapsed rectums.

For every clinical case there are many subclinical cases affecting performance and this may carry on for the life of the animal. Keep in mind these cases will shed thousands upon thousands of these oocysts into the environment (calving area) for other calves to pick up. Calves, being inquisitive, are always picking at manure or drinking stagnant water, the two main sources of the oocysts.

A confirmed diagnosis can be made by your veterinarian looking at a manure sample and doing a float to check for these oocysts. This test is the same one used to determine the worm load in your herd. Bear in mind that in severe cases clinical signs will show up before the life cycle is completed so initially no oocysts are found.

Treatment involves sulfa drugs and products to soothe the gut, such as activated charcoal or kaopectate. I like to finish the treatment with long-acting sulfa boluses such as calf-span to make sure the infection is truly over.

In severe cases veterinarians may need to give a long-lasting epidural (tail block) and put the calves on intravenous fluids. At this stage prognosis is very guarded for the calf returning to normal productivity or even survival. Remember for every clinical case in the herd there are numerous subclinical ones.

Sanitation is key

Prevention involves manure cleaning between calving seasons and spreading it on grain land, much as we recommend for other transmissible cattle diseases such as Johne’s disease. Try and clean it early enough so the drying by the summer sun will kill off additional organisms.

Giving the cow-calf pairs as much room as possible is of great benefit. This is why you will almost never see this disease with producers who calve later on grass and providing lots of space per cow-calf pair.

Any clinical cases should be isolated with their mothers to prevent further spread to the rest of the calves. Clinical disease is the combination of other stresses the calf is under such as scours, pneumonia or navel infection and the number of coccidian oocysts the calf is exposed to.

Treatment for prevention is where the cattle industry has made the most advancement in recent years. Coccidiosis in the feedlot used to be a major economic disease especially in the warmer southern U. S. climates where cattlemen don’t have the benefits of freezing. Freezing does not destroy the oocysts but it at least keeps them in suspended animation frozen in the cow patties. This at least interrupts the life cycle.

With the advent of ionophores such as Monensin (Rumensin) not only do you get the benefits of improved weight gains, feed efficiency and bloat control they are a proven coccidiostat. The use of these and/or similar products in the feedlot has all but eliminated clinical cases of coccidiosis – both the diarrhea form and the much rarer nervous form. The nervous form can come in an outbreak and resembles polio, iteme and other nervous disorders.

Adults immune

The cycle starts because all mature cows have very low levels of oocysts they are shedding into the environment. They are immune to clinical disease and it does not affect their productivity, yet they are exposing their calves to it. Our attack at preventing coccidiosis in the cow-calf sector is twofold. We can treat the cows before and during the calving season with these ionophores (they are safe in pregnant cows at recommended levels) and preventive measures can be started with the calves as soon as they start creep feeding. With a lot of producers using total mixed rations now in silage the ionophore such as Rumensin can be mixed in the ration starting 30 days before calving. This ensures treatment for an entire cycle so when cows are moved into the clean calving area they are not contaminating it.

The normal levels of these ionophores should be continued throughout the calving period. You can also mix these products in free choice mineral or use a specific coccidiostat like Deccox but do this under consultation with your herd veterinarian or nutritionist. Consumption is variable and sporadic with this approach and because it is not the recommended form of delivery you will need a veterinary prescription.

Deccox is a coccidiostat that also works in all stages of the life cycle so even if clinical cases are just starting it may be effective. Our local feed mill has it mixed in with the creep ration and we have our producers use it in creep rations until the calves go to pasture. Generally cases show up in the month to six-week range just about the time calves are becoming interested in creep feed. Our clinic even tried prescripting it into molasses blocks as young calves seemed to more readily consume these. It was more awkward and more producers like the convenience of the creep feed in bags to always keep fresh product out.

Dosing technique

Edith Fontaine in St. Paul, Alberta has a novel and I think very effective way of getting the Deccox into young calves. She mixes six per cent deccox premix at the rate of four cups per gallon of mineral or two cups per gallon of diatomaceous earth in the creep area for the calves. As they start licking they inadvertently take in the product. Deccox is very safe but again pass this by your veterinarian before using it.

Having these creep areas keeps inquisitive calves away from licking dirt, manure and drinking stagnant water all major sources of the coccidian. The snow upon melting washes through manure packs and causes high concentrations of the oocysts in the stagnant water. Try your utmost to not allow young calves access to this stagnant water as the oocyst levels could be sky high.

By using these preventive measures we should be able to all but eliminate this devastating disease from our calves. Remember for every case you treat there are several subclinical ones robbing the calf of its true performance.

Roy Lewis is a Westlock, Alberta-based vet specializing in beef cattle.

About the author


Roy Lewis practised large-animal veterinary medicine for more than 30 years and now works part time as a technical services veterinarian for Merck Animal Health.



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