BVD and the Cattle Industry

Posted by Dr. Brian Dorcey on July 13 2009 15:01

The Industry

• No matter if you are a feedlot operator, a cow-calf producer, backgrounder, or a dairy farmer, BVD impacts your daily life
• This disease is believed to cost our industry over $3 billion per year, in death loss, abortion, decreased milk production, increased treatment cost, and poor feed efficiency.

What is BVD?

BVD is a virus

• Other viruses in this family include the border disease virus of sheep, and hog cholera.
• It was first documented in New York in the 1940's
• BVD may have a reservoir in our wildlife populations (studies are currently underway)

Biotypes of BVD

Cytopathic vs. Noncytopathic

• Laboratory terms...doesn't matter a hoot in the real world, only that most PI cattle are caused by the noncytopathic biotype. One causes just as much disease as the other. 

Type I vs. Type II

• They are related, but distinctly separated
• The dissimilarity between type I and type II BVDV is as great as the dissimilarity between BVD and the hog cholera virus

New Type II Research

• Cattle with an acute type 2 infection usually experience a more severe disease syndrome than cattle infected with type 1
• Type one and Type 2 BVDV each include hundreds of different strains
• Many of our vaccines up to this point have only included type 1

Types of Infection

Acute

• Occurs 7-14 days after infection, lasts for 1-3 days, and is followed by rapid recovery after antibody to the virus has been produced
• Clinical signs can vary, may have one or all of the following
  • Fever, depression, increased respiratory rate, diarrhea, open sores in the mouth, open sores around the hoof and between the toes, and red eyes.

Mucosal Disease

• Mucosal disease is a highly fatal form of BVD seen in persistently infected cattle. They occur when PI cattle become super-infected with another BVD virus, or the one they have undergoes a mutation.
• Clinical signs
  • Fever, diarrhea, ulcers on the mouth and nose, and gradual wasting away. Sores around the top of the hoof and between the claws are common and death with a few days

Persistently Infected

• In utero exposure of the calf to BVD between days 45 and 135 will trick the calf into recognizing the virus as its own tissue and be born persistently infected.
• Persistently infected (PI) cattle shed the virus in mucus, saliva, feces, and urine
• These calves are the "Typhoid Mary's" of the Bovine world

Clinical signs of BVD in calves

• Calves weak at birth
• Unable or reluctant to rise
• Immature (small calves)
• Occasional abortion or mummified fetus
• Dummy calves
• Domed shaped heads
• Birth defects
• Red crusted muzzle
• Cataracts
• Blood clots in the white of the eye
• Occasional skeletal defects
• Poor doing
• Die later from scours, pneumonia, abscesses, etc. (immune dificient)

Bottom line to prevent BVD in your operation

1. Biosecurity!!!
2. Newly purchased cattle should be vaccinated before entering the herd and isolated on the farm for two to three weeks.
3. Colostrum is the first line of defense against BVDV Types 1 and 2, as long as the cow has been vaccinated. This protection usually lasts 4-8 months
4. Design a strong BVD vaccination progam
5. Producers can identify possible PI animals with an ear notch test and cull them to decrease the amount of BVD virus circulating on the operation.
6. Cow-calf producers vaccinate with MLV fetal protection vaccines