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Tackling coccidiosis on several fronts

There are effective treatments, but the best approach is prevention

 This kind of diarrheal mess at the back of a calf is clear sign of coccidiosis.

Coccidiosis can be one of the most frustrating diseases to treat in your 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 and disinfectants, making prevention even more complicated.

Many articles have been written about coccidiosis over the years. Prevention measures have much improved with development of very good coccidiostats treatments, which can be given to the cows ahead of calving or to calves going into the feedlot.

About the disease

Coccidiosis is spread via the fecal oral route and undergoes a 21-28 day cycle. During this cycle this protozoa multiplies 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 partially 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 clinical cases will shed thousands upon millions of these oocysts into the environment (calving area) each day 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 in severe cases clinical signs will show up before the life cycle is completed so initially no oocysts are found.

Treatment options

Treatment, to smooth the gut, involves the use of sulfa drugs and other products such as activated charcoal or kaopectate, but check on the latest treatments available from your veterinarian. I like to finish the treatment with long-acting sulfa boluses such as Calf-span to make sure the infection is truly over.

Since a lot of these drugs may be prescription, discuss with your herd veterinarian for their recommendations. In severe cases veterinarians may need to give a long lasting epidural (tail block) and put the calves on intravenous fluids. Prognosis is very guarded by this stage for the calf returning to normal productivity or even survival. Remember for every clinical case in the herd there are numerous subclinical ones and really the entire herd is at risk for poorer weight gains.

Management practices

Management to prevent future cases involves manure cleaning between calving seasons and spreading manure on grain land, similar as recommended for other transmissible cattle diseases such as Johne’s disease. Try and clean pens or yards early enough so the drying by the summer sun will kill additional organisms.

Giving the cow-calf pairs as much room as possible at calving is of great benefit. It is recommended 2,000 square feet minimum per cow-calf pair. This is why you will rarely see this disease with producers who calve later on grass providing lots of space per cow-calf pair.

Calves showing clinical signs 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 concurrent diseases like scours, pneumonia or navel infection and the number of coccidian oocysts the calf is exposed to.

Prevention is best

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 temperatures to control the pest. Freezing does not destroy the oocysts but it at least keeps them in suspended animation frozen in the cow patties. This interrupts the life cycle.

“Baycox,” a new treatment product, has just been approved for treatment of coccidiosis in cattle and contains the active ingredient “Toltrazuril.” 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 (coccidian killer). The use of these and or similar products in the feedlot has greatly reduced 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.

The cycle

The cycle starts because most 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 two-fold. We can treat the cows before and during the calving season with these ionophores (they are safe in pregnant cows at recommended levels) and preventative measures can be started with the calves as soon as they start creep feeding.

With many producers using total mixed silage rations, the ionophores such as Rumensin can be mixed in the ration starting 30 days before calving. This insures treatment for an entire cycle. When cows are moved into the clean calving area they are not contaminating it by discharging oocysts in the manure.

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 the mineral approach. 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. Even if clinical cases are just starting, it may be effective.

Creep feed option

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 one 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.

Edith Fontaine, a producer 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 coccidia. Melting snow washes through manure packs and causes high concentrations of the oocysts in the stagnant water. Try your utmost to prevent young calves access to this stagnant water, as the oocyst levels could be high.

By using these preventative 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. It has also been found that at pasture when internal parasites are removed by strategic deworming it has a secondary benefit of decreasing coccidian shedding. The theory is, removing the internal parasites strengthens the cattle’s’ immune system.

Always be alert for new advancements in the treatment of the protozoan diarrheal diseases, coccidiosis and cryptosporidiosis. There is also currently work being done at the University of Calgary in the veterinary faculty looking to “type” specific coccidia as only two are considered very pathogenic in cattle. Depending on the mix of coccidian present we can treat or prevent when necessary. Watch for further developments in our treatment and/or prevention against coccidiosis.

About the author


Roy Lewis is an Alberta-based veterinarian specializing in large-animal practice. He is also a part-time technical services vet for Merck Animal Health.



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