Johne’s disease strikes herds silently


COLUMBUS – Production losses.

Premature culling.

Loss of marketability of breeding stock.

Johne’s disease (pronounced YO-knees), which has been around for more than 100 years, is now considered a major disease problem for the cattle industry.

And Ohio State University Extension specialists want Ohio sheep, goat and cattle producers to be more aware of it.

Bacterial infection. Johne’s disease is a chronic bacterial intestinal infection that strikes silently and is hard to get rid of, says Bill Shulaw, an Ohio State Extension beef and sheep veterinarian.

It can affect a large proportion of the herd and cause

Johne’s disease is caused by a bacterium called Mycobacterium avium subspecies paratuberculosis (MAP), a hardy germ related to those that cause tuberculosis and leprosy.

Current estimates from the USDA place the prevalence of the disease at about 22 percent of dairy herds and 8 percent of beef herds.

Shulaw calls those estimates “conservative.”

This year, the USDA gave about $20 million to the states for Johne’s disease control efforts.

Often undetected. Johne’s disease strikes beef cattle, dairy cattle, sheep and goats.

It can cause large economic losses to the industry because of its ability to strike animals at a young age, yet remain hidden for many years.

Once it’s identified in a home-raised animal, chances are the rest of the herd may also be infected.

A study conducted in 1996 by the USDA’s National Animal Health Monitoring System estimated a $200-250 million loss to the dairy industry alone because of the disease.

Spreading infection. “Animals may shed MAP in their manure for months to years before they show signs of the disease,” Shulaw said.

All the while, the animals could be spreading it to other young animals in the herd.

The number of organisms that it takes to spread infection under a field setting is not well established, but Shulaw said somewhere around 1,000 to 10,000 organisms may be enough.

Because infected animals may shed millions of the bacteria in their manure daily, the potential for contamination of the young animal’s feed or environment is very high.

“If you were able to mix the manure from a single cow shedding 1 million organisms per teaspoonful with the manure of 99 cows that were not shedding any, the resulting mix would still contain 10,000 organisms per teaspoonful,” he explained.

Colostrum at risk? In addition to spreading through manure, research suggests that the bacteria are finding its way in the energy-antibiotic-rich colostrum, or first milk that calves receive from heifers.

“If the udder of a cow is dirty and you get wash water down the side of the udder while milking, only a drop or two of manure at a concentration of a million bacteria per gram is enough to contaminate a 5 gallon bucket of colostrum,” Shulaw said.

“Virtually all calves fed out of that bucket might be infected.”

Symptoms. Shulaw said signs of Johne’s disease in cattle include chronic watery diarrhea that does not respond well to treatment and severe weight loss.

In infected sheep and goats, diarrhea does not normally occur, but severe weight loss is evident.

The key to control the disease is sanitation and preventing young animals from ingesting the bacteria.

Buying animals. Shulaw recommends asking about the status of a seller’s herd before purchasing if possible.

“Purchasing animals from herds participating in a testing program, such as Ohio’s Johne’s Disease Test-Negative Status Program, and finding out how long they have been testing is far, far less risky than buying from herds with unknown status,” Shulaw said.

Johne’s control practices

* Reduce environmental contamination by identifying infected animals and culling them from the herd.

* Provide clean, well-drained areas for calving.

* Remove cow and calf pairs from the calving area as soon as possible after calving and place them on uncontaminated pasture or in clean facilities.

* When possible, raise heifers separate from adults. Do not spread manure on heifer pastures.

* Isolate unthrifty animals or animals with diarrhea until a diagnosis is made or until the animal is culled.

Get the details





March 9      

Salem First United Methodist Church, 244 S. Broadway, Salem, Ohio; 12:30-3 p.m.; Extension contacts: Ernie Oelker 330-424-7291 or

Millcreek Metroparks Mahoning County Farm, McMahon Hall, 7574 state Route 46, Canfield, 7-9:30 p.m.; contacts Ernie Oelker.

March 10

Ohio Agricultural Research and Development Center, Wooster, 1-3:30 p.m.; contact Tom Noyes, 330-264-8722, or; or Roger Amos 419-281-8242.

March 15

Knights of St. John Hall, Maria Stein, Ohio; noon-3:30 p.m. Food will be served and a registration fee will apply. Contact Joe Beiler, 419-586-2179 or, or Steve Foster, 937-548-5215 or

Shelby County Extension office, 810 Fair Road, Sidney, Ohio; 7-9:30 p.m.; contact Beiler or Roger Bender, 937-498-7239.

March 24

Highland County (location to be announced); 7-9:30 p.m.; contact John Grimes, 937-393-1918 or; or Jeff Fisher, 740-947-2121.


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