Johne's Disease and PCR Testing

[Lonesome Pine]

Hello All,
Looking for help in assessing the result of a PCR test done on our 9 year old Jersey/Aberdeen cross cow. We had the vet out for another reason but while here she witnessed diarrhea from this cow. I had wormed everyone about a month ago and was concerned that perhaps the Bovimectin pour on hadn't worked for her. No sign of worms in test result but I authorized the vet to do the Johne's test, never thinking it would come back positive. So, the test was performed 36 rounds, with the limit being 42, before the shedding of the anti-bodies was found. She is healthy, eating well, no body condition change and about to calve.
Any thoughts would be most appreciated.
Many thanks,
Mary

 

[Stickney94]

It's been a bit since I had Johne's testing done -- my recollection was that blood was drawn and the test results came back in a range. Are you saying that the animals score was 36 out of 42 -- so high likelihood of positive? What did your vet recommend?

With that said, Johne's is a devasting disease to have in your herd. If you have an animal that tests as a potential carrier I'd cull the animal immediately.

 

[A.J.]

Hi Mary. I'm sorry to hear she has Johnes. That puts you in a tough predicament since she is about to calve. If she were mine, I would still go ahead sell her as soon as possible to help minimize the risk of further spread to the rest of your herd. If you don't want to sell her before she calves, I would quarantine her away from the rest of your herd, and sometime soon test the rest of your herd to see if any of the others might have it as well. Testing can be difficult though, as others might be carriers, but not test positive for it yet. That's one of the tough things with Johnes is they typically keep a strong appetite and seem fine overall other than the diarrhea, until they get in advanced stages and start losing weight rapidly. Many times stressful events like calving can trigger it and they can go downhill fast. @Lucky_P on here is a great source of information for this from a veterinary perspective.

 

[Ebenezer]

It's been a bit since I had Johne's testing done -- my recollection was that blood was drawn and the test results came back in a range. Are you saying that the animals score was 36 out of 42 -- so high likelihood of positive? What did your vet recommend?

With that said, Johne's is a devasting disease to have in your herd. If you have an animal that tests as a potential carrier I'd cull the animal immediately.

PCR is more accurate than the blood test from what I have read.

 

[SBMF 2015]

I've delt with a few Johnes cows over the years for other producers. There's a smell you'll never forget.
If a cow comes up suspect or positive on the blood test then quarantine and PRC test them.
I have never knowingly put a Johnes positive cow in the food chain. We have always destroyed them.

 

[CVHFarmsLLC]

I suspected Johnes in our herd at one point and remember a bit about the diagnosis. If I remember correct, you would be pretty safe with a nine year old cow as I believe Johnes symptoms shows at a much younger age. I guess maybe there is a chance it was picked up later in life.

As others have said, PCR is most accurate. We had a positive around 38 of 42 (I could be off a bit). I talked with the head vet at the Texas A&M lab and he explained that it could easily be a false positive. We now suspect it was acidosis I caused by poor feeding decisions I made in our first year in the business. We culled the cow and have had zero signs of Johnes since. I guess my point is, there is a reasonable chance something else is going on and you don't have Johnes. Looking back now, I laugh about it because I was absolutely convinced we had it and I had ruined our family's cattle business.

 

[pfox]

I just purchased a farm and someone informed me that prior to me buying it, there had been Johnes on the farm. After doing some research, it seems like a serious, hard to eliminate disease. last year I purchased about 10 cows who have now calved, should I be concerned about the existing corral area which has been used a bunch. Should I be concerned about my cows getting this through the manure throughout the farm? I don't remember worrying about this with my cattle in No. CA so I appreciate any help or suggestions.

 

[SBMF 2015]

I just purchased a farm and someone informed me that prior to me buying it, there had been Johnes on the farm. After doing some research, it seems like a serious, hard to eliminate disease. last year I purchased about 10 cows who have now calved, should I be concerned about the existing corral area which has been used a bunch. Should I be concerned about my cows getting this through the manure throughout the farm? I don't remember worrying about this with my cattle in No. CA so I appreciate any help or suggestions.

The time lapse between the previous infected cattle being there and you cows now should be a big help.
Clean things up the best you can.
Young calves are more susceptible than adults.
Overall I'd think your pretty safe.

 

[farmerjan]

We had a bull show up with Johnes..... a bought bull...a year after we had bought him.... Vet was there to do preg checks, blood tested the bull, he was "loose" and losing some weight, but he looked suspect. Came back positive... off the chart he said.
Bull had been isolated in one lot and the vet said to not let any breeding animals, cows/calves have access to that field for 18 months... By then the manure would be worked into the grass/ground. The bacteria has a normal "life" of about a year...so after 18 months it was pretty sure that the bacteria had died and the manure had been incorporated into the soil. We have never had a problem with it since... no one getting loose manure etc... we buy and sell some cattle so have a higher possibility of them being exposed somewhere.
It is less common in beef cattle than in dairy cattle, but beef people are getting more aware of the problems. Usually it is triggered by a "traumatic" event... such as calving.. that causes the animal to start losing weight and such... it can live in an animal and you never know it and the animal gets culled.
Clean the facilities as best you can , and make sure you calve the cows on ground that is green grass with as little manure residue as possible.

 

[suzorse]

cows get Johnnes as calves by ingesting manure or colostrum from a positive cow , and it usually shows up when they are older 5+ , I bought a 300lb dairy heifer , and after she had calved her calf got an ear infection so I did a milk test looking for Mycoplas , and went ahead an tested for BLV , BVD and Johnnes , she came back positive for Johnnes , so vet run fecal tests on all 3 of the cows I had and she was positive also on the fecal , she had been kept seperated since before calving and was just 2 years old , I had been milk testing all new cows before leaving Quarantine, but since she was a heifer she was not done after her 30 days , you can run steers on a pasture after a positive cow as they generally do not live long enough to shed the virus , dry pastures (non irrigated ) 1 to 2 years , irrigated wet environments it will last longer in the soil , I also tested every 6 months afterwards and now do yearly when I do my TB and Brucellosis testing , only way to keep the calf is to keep her in quarantine and do not wear the same shoes for her as any where else , and as soon as she calves pull the calf immediately and give colostrum from a neg cow , and then cull the cow and deep clean the pen and the equipment used for cleaning the pen , this would be only if she was close to calving
Suzanne

 

[redcowsrule33]

In some cases it can be transmitted in utero so even isolation from the dam at birth isn't 100%.