Management Issues

Home

Archives

Article in Print

Johnes: Manage to Solve the Problem

August 2004

“When trying to control Johne’s, make sure you identify the areas that create the problem,” Dr. Victor Eggleston told an audience of more than 80 members of the American Jersey Cattle Association during a seminar on the disease.

When making decisions to prevent, manage or even eliminate the disease, Dr. Eggleston advised, “You have to treat each herd as an individual. You can’t make one recommendation and expect it to work for all the herds.”

Dr. Eggleston, New Glarus, Wis., reported on findings from an ongoing, five-year field demonstration that he is conducting with Dr. Mike Collins of the University of Wisconsin Veterinary School, Madison, Wis. Eggleston practiced veterinary medicine for 35 years and is a past president of the Wisconsin Veterinary Medical Association.

Details of the Study

“The idea for the project started from a subcommittee of the Wisconsin Milk Marketing Board,” explained Eggleston, who credited the role of Jersey breeder and committee head, Dr. Michele Weighert, with its start.

“The main purpose of the study was to see if recommendations really work in the field,” said Dr. Eggleston.

“We decided to take a cross-section of the state: different breeds of cattle, different management styles and different environments,” Dr. Eggleston added. “We ended up with eight Holstein and two Jersey herds.” Herds ranged in size from 70 to 1,200 milking cows and were managed in tie-stall and freestall barns.

“The basic requirements we had were to blood test all lactating cows in the last third of their lactation, identify the test positive cows, collect colostrum from only test negative cows and cull test positive cows before they freshened again,” explained Dr. Eggleston. Researchers Collins and Eggleston also asked to “have more than one maternity pen, get (calves) out of the pens as quickly as possible, and administer four quarts of colostrum to newborns.”

As part of the study, “six different tests were run on individual cows in these herds. The tests included two different blood tests, three different fecal tests from different labs and a milk test.”

“However, only the results from the blood tests were reported to the farmer,” added Eggleston. “The concept was to see if just a blood test could lessen the impact of Johne’s disease in the herd.”

Dr. Eggleston advised, “If you are heading into testing, don’t put a lot of emphasis on the numbers of individual cows. These tests were primarily designed as herd tests and not for specific cows. All you are looking for is a general concept of where you are.”

He added, “We ran fecal cultures at different places and sometimes got different results. As well, they did not always match the blood and milk test results.”

Cull Heavily Infected Cows

Dr. Eggleston’s number one recommendation to producers: Cull all cows that are heavily infected, those that are strong positives.

“When they hit strong positive, cows don’t last,” Dr. Eggleston commented of the five levels of blood tests. Results range from negative, suspect, low positive, positive to strong positive. Strong positive cows “may look good, but they are not going to last another lactation.”

Explained Eggleston, “It takes three to five years for (Johne’s disease) to occur. It builds up so much scar tissue that animals can’t absorb any nutrients any more. That’s part of the reason why you see diarrhea and why they go downhill so quickly. They just aren’t able to retain the nutrients they take in.”

After 35 years of veterinary practice devoted to dairy cattle, Dr. Eggleston knows the decision to cull a strong positive cow may be a tough one for some dairy producers to make, especially if they are short on cows or if the cows are milking heavily.

“They don’t have to get rid of them right away, just don’t calve them back on the farm,” Dr. Eggleston advised.

Management Changes in the Calving Area

“Start out in the most important area: the calving area,” remarked Dr. Eggleston. “Make it clean and dry and get the calves out as quickly as possible.”

Some other recommendations, “Don’t pool colostrum. Don’t feed waste milk. And don’t house calves close to adults.”

Dr. Eggleston recommends feeding milk replacer rather than whole milk or pooled milk. Even better is the practice of feeding pasteurized milk.

Other Management Considerations

“Don’t assume anything when it comes to Johne’s disease,” warned Dr. Eggleston. “The primary objective is to keep the Johne’s contaminated manure away from heifers. Find any way you can to make sure they do not get exposed to adult fecal material.”

Dr. Eggleston advised patience and persistence in dealing with Johne’s disease. “If you make any changes right now, it’s going to be three years minimum before you see the results of those changes relative to a lower number of Johne’s-infected cows,” said Dr. Eggleston.

“But, as soon as you start testing, you’ll spend more time looking at the results and comparing them to the actions and activities of the cows,” he explains. “All of the sudden, you’ll spot these cows sooner and move them out sooner, before they actually go clinical. So, the fact is that you do see less clinical animals as soon as you start testing, even though it is not a direct result.”

Risk Assessment Programs

“One of the things the federal government is doing to help is to train veterinarians on risk assessment and management,” remarked Dr. Eggleston. “The USDA is providing funds to states and making them available to vets who will take the training.”

“The purpose of risk assessment is to find the areas that contribute to the disease,” Eggleston explained. “The training includes information and background on the disease and various tests and their significance. The veterinarian is then paid to go out and do the assessment on the farm. They use a standardized point system to evaluate management areas, identify the problem and formulate plans for correcting the problem.”

“Basically, (veterinarians) are outlining steps that (dairy producers) can go through to eliminate contamination of manure, establish a priority for each one of these and decide who is going to be responsible for taking care of it,” said Dr. Eggleston.

“Often, producers and veterinarians don’t have enough time to look at these areas closely,” Dr. Eggleston stated. “The program works out really well.” The visit addresses only the issues related to Johne’s disease and the producer doesn’t have to pay for a special vet visit.

Purchasing Animals

“Probably the best way to pick up disease is by buying somebody else’s problem,” remarked Dr. Eggleston.

He relayed research from Iowa State University that indicates 59 percent of dairy producers purchase cows from unknown sources. Eggleston encouraged cattle purchasers to do some homework before purchases are made. He added, “I think there are more than 60 percent who don’t know where they came from. They might buy them from cow jockeys. They might actually have different sources.”

Dr. Eggleston recommends doing as much as you can to learn about the herd from which you are purchasing. “Examine herd health and vaccination records and try to obtain a bulk tank sample,” he says. “Ideally, get the Johne’s disease test results from the herd.”

“If you are planning on expanding, ask your veterinarian to set up a plan for biosecurity for facilities,” advised Dr. Eggleston. “Quarantine animals when they come in. Have a separate hospital and area to milk the cows and do some pre-purchasing checks.”

“The term biosecurity has been thrown around a lot,” commented Dr. Eggleston. “Biosecurity means security against any biological disease on the farm. You can do a lot of this without ever buying an animal.

“I’ve heard people say they’ve got a closed herd, so the can’t get Johne’s disease,” Dr. Eggleston remarked. “Believe me, it can happen.”

In summary, Dr. Eggleston’s recommendations are pretty simple. “Keep things clean. Identify the (infected) cows and keep them segregated. Don’t use colostrum from infected cows. And cull heavily infected cows.”

A question and answer period followed Dr. Eggleston’s formal presentation. Some of the questions Jersey breeders asked of him are shown below.

Q: What is the difference in the reliability of test results between younger animals and older animals?

A: If you test an animal and the result comes back positive, then the animal is positive. The catch is that there are a lot of positives that won’t test positive as young animals. There is no guarantee that some younger animals that initially test negative will not test positive later on. A test will identify the bad ones, but not necessarily all of them.

Q: If vaccines work, why don’t all states allow for their use?

A: There are other issues related to their use, namely safety for veterinarians and dairy producers. And, if you manage your herd right, you won’t need it. If the vaccine were as user-friendly as the vaccine for BVD and IBR, I would recommend it.

Also, there are a lot of dairy producers who would like clean herds. Animals from herds with a Level-4 for Johne’s disease (in Wisconsin) are valuable. You can never reach Level-4 using vaccinations because the animals are constant carriers. With the vaccine, you’re giving them the disease. It’s not active, but it’s still there.

Q: You seem to be saying that the ELISA blood test is a better way to diagnose and manage Johne’s than the fecal test. In New York, it seems we are opting for the other way. With fecal tests, the results are black and white (either positive or negative). Which method should we use?

A: First, the state of New York is paying for fecal cultures. My project was to see if the ELISA test would do the trick, practically and economically. However, we did run fecal cultures on these same cows. Ironically, two of the three labs that performed baseline fecal cultures did not always agree. It is my feeling that the ELISA test, along with improved management, will reduce Johne’s in most herds. If you are a purist and want to get rid of every organism on your farm, the ELISA test is not practical. A fecal test will do it faster. But you need the dollars to do that.

Q: Where are we in terms of being able to pull milk samples and check for Johne’s that way? And, how accurate are the results?

A: Right now, Michigan Dairy Herd Improvement Association is the only one that offers testing at the time milk samples are taken, through Antel Bio.

When comparing the milk test to fecal tests and blood tests, it fared pretty well. It was not as sensitive, so did not pick up as many positives as the blood test. But, when it indicated that a cow was positive, she was. As well, it did not give false positives and that is a critical issue with a test.

The milk test provides results almost immediately. Basically, the process is the same as the blood test. There is more time in transporting samples and results back and forth than performing the test in the lab.

Q: At what age is susceptibility to Johne’s disease no longer an issue?

A: I don’t think there is ever a point when they cannot be affected. Certainly, though it takes a considerably larger load on a cow to create a problem than on a calf because the cow has developed so many more immunities. Additionally, if a cow gets exposed to Johne’s disease when it is 30 months-of-age and lasts until it is 40 month-of-age, it will not be around by the time the disease would take affect anyway.

Q: What level do you consider to be a high-risk cow?

A: That depends on the test that is run. If we look at the simple, positive or negative blood tests, the results are bothersome. Some of the cows may be close to the positive level but still read negative. In the case of the five-level blood tests (negative, suspect, low positive, positive, and strong positive), be sure to label your low positives and positives and watch them. Some of these cows might be going out for some other reason, but they can still be potential contaminates for your calves. Make sure the calves from these cows get out of the pen as quickly as possible.

Q: How often do you recommend testing an animal?

A: Once a year when the animal is dried off. Some of the larger herds have asked us to test the animals before they are bred. In that way, they are not spending cash on synchronization programs and semen. They can keep the cow as long as she’s profitable but don’t have to spend money breeding her back because they know they won’t keep her anyway.

Editor’s Note: The University of Wisconsin has a website devoted to Johne’s disease. Visit www.johnes.org for more information on the disease.