QUESTION: I have a 6-year-old cow that is wasting away. My neighbor says the cow has Hardware disease, but my veterinarian thinks it could be Johne's. The blood test for Johne's was negative. What do you think?
ANSWER: Johne's disease is a chronic wasting disease. Cattle are most susceptible when they are young. Infected cows shed the bacteria in their stool and young cows ingest the manure. Infected cattle can take years to show clinical signs. The most common symptoms are diarrhea and weight loss. A positive on the blood test means the animal has Johne's, but a negative does not mean the animal isn't incubating the disease.
We use a fecal culture in which we try to grow the bacteria in the lab. This takes up to 16 weeks but is more accurate. With Hardware disease there is no definitive test outside of exploratory surgery.
Both Johne's and Hardware are best dealt with by prevention. Wire, nails or other small metal pieces a cow might eat should be cleaned up. Johne's bacteria are best transmitted through mud and manure, so muddy areas should be eliminated as much as possible. Watering areas, feed troughs and equipment used for feeding should be kept clean.
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