Testing for persistent infected bovine viral diarrhea in cattle can be beneficial.
Often producers look at the expense of something not realizing that a small investment in one test could save several more dollars in the long run. I believe testing for P.I. BVD in animals is a no brainer when it comes to backgrounding calves or even in some cow herds. One P.I. animal will cost the producer a lot of money in terms of abortions, lowered conception rates, weight loss and medical expenses than for the testing expenses for that pen of animals.
First some producers will ask what is P.I. BVD? When a cow becomes exposed to pathogenic form of bovine viral diarrhea virus (BVD) between 40 and 125 days of her pregnancy that offspring in that cow may become persistently infected with BVD virus. This means that the calf as it is born and grows will not be able to fight off the BVD infection, and therefore will persistently be infected with the BVD virus. Infected cattle can shed millions of virus particles daily within the environment causing a constant exposure to all of the pen or pasture mates. A non P.I. cow exposed to pathogen BVD virus at 40 to 125 days of gestation can produce a P.I. calf. It is important to test all calves born before turning out the bull to eliminate any calves that test positive. A producer should always check open cows that do not calve during that calving season as well. Even the bull should be tested for persistently infected BVD.
In a backgrounder situation, I believe that one should quarantine all new animals and test them, culling all that are infected. Individuals will make a big difference not only in that pen of calves but all the cattle in that pen. A P.I. BVD cow/calf within one pen or even adjacent pens will cause enough stress that a tremendous amount of expense will be inccurred in weight loss, feed, efficiency, death loss and vaccinating and antibiotic therapy.
The testing procedure is simple and very inexpensive. The test can also be done by the producer without the need of the veterinarian. To test for P.I. BVD a small ear notch is taken from the animal, put in a test tube, labeled with the animal’s I.D. and sent to a lab that test for P.I. BVD. Some testing facilities will supply the tubes, which have a small amount of preservative in them as this helps preserve the sample during shipment. Call your local veterinarian to see which lab he/she recommends.

Things to Remember:
1. Not all P.I. BVD animals will look sick. Some of them will not show any sings at all.
2. P.I. BVD infected animals are not the only expense. A major expense will occur due to abortion, weight loss, medical expense and even sometimes death.
3. Vaccinations are not 100 percent effective. Vaccine failure can be related to stress, nutrition or maternal antibodies.
4. Vaccinations alone will not stop P.I. BVD.
Dr. Rusty Waide, DVM, has been the owner of Buffalo Veterinary Clinic in Buffalo, Mo. for 21 years.


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