- This virus is in our cattle herds and is causing significant problems.
- Transmission between animals is by direct contact.
Persistently Infected (PI) animals are the major source of infection in the herd:
- All persistently infected cattle are first infected when they are a fetus
- These persistently infected calves can be born normal and grow to a mature animal, some are unthrifty, and others look normal.
- A persistently infected animal will shed BVD virus in the herd all of its life. The only way to stop shedding the virus is by natural death or slaughter.
- Day 0-42 of pregnancy: infertility, abortions, early embryo death
- Day 42-125 of pregnancy: results in a persistently infected fetus
- Day 125-180 of pregnancy: birth defects, deformed or weak calves, stillbirths, cloudy eyes, poor doers etc. (Sometimes these symptoms are confused with vitamin or Selenium deficiency, or poor nutrition. That is the feed company gets blamed, if feed was bought. Sometimes it gets blamed on genetics or the bull supplier). Usually it is BVD.
Mucosal disease: (Syndrome of persistently infected animals)
Signs: Depression, off feed, diarrhea, fever, sores in mouth. Usually happens shortly after weaning but can happen up to two years of age.
Respiratory disease: BVD virus contributes to pneumonia outbreaks in feedlots. The BVD virus is commonly detected in calves that die of pneumonia.
Control of BVD comes down to VACCINATION
– Maintain high immunity in the cowherd.
- If infection does occur, the cow’s antibodies will remove the virus,before the fetus is infected.
- This is best done with a modified-live vaccine given to cows 3 weeks prior to breeding.
It has been proposed that within the next 10 years, there will be a move in the cattle industry to eradicate BVD. This will mean testing all animals and culling all the carriers. One can anticipate that this will probably be met with as much enthusiasm as did the CCIA cattle identification or the current gun legislation.
Contact your local veterinarian for more information on how to control this silent killer disease.