BVD virus can be a problem

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 By David Kessler

Marion County Agent for Agriculture and Natural Resources

 The Marion County Cattlemen’s Association held its regular meeting on June 3 at Floral Hall. Dr. Beth Johnson, DVM from the Office of the State Veterinarian, spoke on the topic of calves persistently infected with the BVD virus. 

I wrote about this disease in cattle several weeks ago, but Dr. Johnson provided some details and new information that could help understand and combat this disease.

BVD stands for Bovine Viral Diarrhea, but Dr. Johnson said the actual diarrhea effects of the disease are usually minimal. The worse affects from the disease come from severe cases that cause suppression of the immune system, which allows the animal to contract separate diseases like pneumonia or other respiratory diseases. BVD is a virus, which cannot be treated with antibiotics. Newborns normally get antibodies from their mother and vaccinations can help animals fight the disease if they are exposed to it. 

Persistently infected or PI-BVD cattle can be born to cows that are infected with the BVD during the first 20 to 150 days of pregnancy. During this period the fetus’ immune system is developing and it thinks the BVD virus is normal so it does not recognize the vires as a pathogen; for the rest of its life the animal’s immune system does not try to fight the virus, hence it is persistently infected. 

The animal may or may not have symptoms of the disease but the virus is always present and can be spread to other animals the PI animal comes into contact with. One animal can infect the entire herd with BVD, which causes the immune system repression that leads to other diseases. 

These widespread illnesses can be costly at best and devastating at worst when multiple animals die from the associated diseases. Worse is if the PI animal is still in the herd it can infect animals that do recover.

The good news is the BVD virus has no effect on humans; eating beef from animals with PI-BVD or transient BVD infections has no ill effects. 

Also, less than half of one percent of all calves are PI, a calf cannot become PI infected after it is born, although it can be transiently infected, and testing for PI-BVD is very inexpensive when compared to the value of the animals in the herd, about $3 to $4 per head.

Dr. Johnson said the best way to prevent PI-BVD calves is to test all calves for PI. If any are positive, check their dam for PI. If a cow is PI infected her calf will always be PI infected. This will weed out existing presence of PI in the herd. In a closed herd this should only need to be done once if ongoing BVD vaccinations are maintained. To keep the herd BVD free, vaccinate all cows and heifers thirty days prior to AI breeding or turning bulls in with the females. Dr. Johnson recommends a modified live vaccine, but consult your veterinarian for the best possible option. 

Vaccinate all calves 30 days prior to weaning and booster at weaning with a modified live vaccine. All new additions to the herd should be isolated and PI tested. 

New animals should have BVD vaccinations prior to entering the herd. If you have bred cows entering the herd and are unsure of their vaccination status, consult your veterinarian for appropriate action as using modified live vaccines during pregnancy may cause abortions. 

All bulls should be PI tested prior to entering the herd, but remember that this only needs to be done once; if an animal is born PI free it cannot become PI infected.

PI-BVD has probably always been around but we never had a way to test for it. There have always been poor performing animals and herds where it seems every animal suddenly becomes sick. 

If we test and find we have a PI animal we may lose on that animal because it is illegal to sell it or move it from the farm without a permit from the State Veterinarians Office, but the rest of the herd will be much healthier and perform much better than it would if that animal were to remain in the herd unidentified. 

A number of people at the meeting asked if they could get a copy of Dr. Johnson’s PowerPoint presentation. She has sent it to me. Call the office and we can email or send you a copy. If you would like help getting your herd tested call your veterinarian or call me at the office and I can get you more information.

The Central Kentucky Premier Heifer sale was held this past Saturday at the Marion County Fairgrounds. Farmers from Marion and Nelson Counties sold 143 bred heifers due to calve this fall. The combination of a very robust cattle market and the high quality of livestock offered for sale resulted in an all-time high average sale price of $2344 per head. 

The Marion County Farmers Market is now open on both Wednesdays and Saturdays from 9 a.m. to 2 p.m. at the Farmers Market pavilion on M. L. King Avenue. 

A wide selection of fresh produce, canned items, baked goods and crafts will be available. All items are produced in Marion County so you know you will be supporting our local farmers! 

New vendors are always welcome. If you are interested in selling at the market call the extension office for details.

The next Beekeepers Meeting will be tonight, Wednesday, June 11, at 6:30 p.m. at the Extension Office.

We will have a Tobacco Field Day on July 24, at 5 p.m. at Steve Downs’ farm. UK Tobacco Specialist Bob Pearce has arranged demonstration plots of no-till, strip till and conventional tillage with 11 different varieties of tobacco. We will provide more details as we get closer to the field day.

The next edition of the Container Gardening Classes will be held Thursday, June 19, at 5:30 p.m. at the Extension Office

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