Johnes disease can cost beef and dairy producers thousands of dollars each year. Not only do Johnes infected cows give less milk, but they also must be culled if the infection is found. Replacement heifers that test positive should be culled to protect the health of the rest of the herd. Once cows reach stage 3 of the disease, the poor body condition means that they will not bring as much money at the sale yard.
It is definitely important to be proactive in handling this disease. If you have a Johnes positive animal on your farm, you should work with your vet to figure out the extent of the infection. If the animal is new to the herd, most of your adult animals should be reasonably safe.
If you have a cow that seems to be eating well, but keeps on losing weight, you may want to go ahead and test for Johnes. The blood tests (ELISA, AGID and complement fixation) are fairly inexpensive, and you get results quickly. If you have a positive result of Johnes blood tests, it is certain that the cow had the disease and she should be sold for slaughter as soon as possible. However, blood work often comes back with false negatives, so if you get a negative, you should have the vet run a fecal test just to be on the safe side.
Fecal tests are considered the \"gold standard\" test for Johnes. The manure is cultured in petri dishes, and the lab observes what grows after several weeks. Fecal tests are very reliable, and they can detect MAP organisms years before the farmer notes any clinical signs of Johnes disease. The downside to this test is that fecal tests take several weeks to complete. These tests are also more expensive than blood tests, so if you have many cows that need to be tested, you can run into quite a bill from the lab.
Protecting your animals from this illness is less complicated than you might think. Of course, ensuring that animals brought on the farm are disease-free is crucial to keeping your herd safe from Johnes. A simple blood test can tell you within just a couple of days if new cows are infected. If you get a negative, you probably will want to run a fecal test to make doubly sure. You should also quarantine any new animals until you are sure about their health status.
If you have had Johnes on your farm in the past, or you are unsure about the status of your herd, simple sanitation can go a long way toward protecting your animals. Keeping calving pens clean from manure can help minimize the exposure of calves to potentially dangerous manure. Additionally, make sure that no cross contamination occurs on your farm. For instance, you should have separate tractor buckets for managing feed and manure. This is a good practice to get into anyway, just as a general herd health precaution. You should also be careful with feeding colostrum to newborn calves. Only feed colostrum from cows that you know are Johnes-free.
Johnes sounds scary, but with proper management, you can eliminate it from your herd and protect your healthy animals from the MAP organisms. The first step is to educate yourself on how it is transmitted and spread. Speak to your vet about your herd\'s risk for Johnes.
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