What is the viral disease of cattle called?

There are many viral diseases of cattle, so it's difficult to say which one is the "most" viral. Some of the most common and impactful include:

* Bovine Viral Diarrhea (BVD): A highly contagious disease that can cause severe illness and death in calves.

* Foot-and-Mouth Disease (FMD): A highly contagious and devastating disease that can cause severe economic losses.

* Bovine Respiratory Syncytial Virus (BRSV): A major cause of respiratory disease in cattle, especially in calves.

* Bovine Herpesvirus 1 (BHV-1): A common cause of respiratory disease, abortion, and neurological problems.

* Infectious Bovine Rhinotracheitis (IBR): A highly contagious respiratory disease that can cause significant losses in cattle herds.

* Bovine Papillomavirus (BPV): Causes warts on cattle.

It's important to note that there are many other viral diseases that can affect cattle, and the prevalence of specific diseases varies depending on the region.

Can you be more specific about what you're looking for? For example, are you interested in a specific type of virus, or the most common viral disease in a particular region?