- BVDV is a highly contagious virus that can infect both beef cattle and dairy cattle
- Most infections are subclinical, meaning cattle show few or no signs
- The virus mutates and changes over time
- The most common BVDV subtypes include Type 1b, which is the most prevalent strain, Type 1a and Type 21
- BVDV can contribute to reproductive disease (abortions, persistently infected calves and birth defects), respiratory disease and, less commonly, diarrhea
How BVDV Is Spread
![Image showing how vertical transmission of BVDV can move in cattle](/cattle/sites/default/files/2023-11/HowBVDVSpread-Chart1.png)
1. From a Persistently Infected (PI) Dam to the Fetus:
If they’re able to viably gestate, PI dams will always produce PI calves. Many will die before 1 year of age; others typically show no clinical signs.
![How BVDV spreads portrayed in graphic form](/cattle/sites/default/files/2023-11/HowBVDVSpread-Chart2.png)
2. From a Transiently Infected Dam to the Fetus:
Calves that become infected in the uterus can be born PI, spreading the virus for a lifetime.
![How horizontal transmission works in Cattle BVDV](/cattle/sites/default/files/2023-11/HowBVDVSpread-Chart3.png)
3. From PI or Acutely Infected Cattle to Healthy Cattle:
Infected animals can shed the virus in saliva, nasal and eye discharge, urine, feces, milk and semen. Infection then occurs from nose-to-nose contact or when the virus is ingested or inhaled.
Two Types of Infection
![Persistent infection - 5% of infections](/cattle/sites/default/files/2023-11/TypesOfInfection-Chart1.png)
- 1. Acquired from dam while in uterus
- 2. Lasts a lifetime
- 3. Major source of viral shedding
![Transient infection - 95% of infections](/cattle/sites/default/files/2023-11/TypesOfInfection-Chart2.png)
- 1. Acquired from other animals after birth
- 2. Lasts a few weeks
- 3. Minor source of viral shedding