BVD (Bovine Viral Diarrhoea)

What is BVD?

Bovine viral diarrhoea (BVD) is a virus disease of cattle, and buffaloes can be infected too. Despite its name, diarrhoea is only one of its effects. The virus weakens the immune system, so pneumonia, scours and other infections hit harder. Many infected adults show mild signs or none at all.

The most important feature of BVD is the persistently infected (PI) calf. If a cow is infected in the early months of pregnancy, the virus can cross into the unborn calf, which may then be born infected for life. PI calves may look normal or may be small and keep falling ill, but they shed large amounts of virus all their lives and are the main way BVD keeps spreading in a herd. Some PI animals later develop mucosal disease, a severe, usually fatal form with mouth sores and diarrhoea. BVD does not infect people.

Signs to watch for

Common signs include:

• Diarrhoea, fever and a drop in milk
• More pneumonia and calf scours than usual
• Repeat breeding, early pregnancy loss or abortion
• Weak, small or deformed calves
• Calves that grow poorly and keep falling ill
• Mouth sores with severe diarrhoea in young animals

Not every animal shows every sign. Because signs are often mild or mixed, BVD is easy to miss without testing.

Which lab tests help

The BVD Antigen ELISA finds infected and PI animals by detecting part of the virus in serum or an ear notch (a small piece of ear skin). BVD Virus RT-PCR finds the virus's genetic material in serum, blood or an ear notch. In young calves, antibodies from colostrum can affect some blood tests, so your vet will choose the right sample.

A single positive result can come from a short-lived infection that the animal clears, so a second positive test some weeks later is used to confirm a PI animal. The BVD Antibody ELISA shows whether an animal has met the virus or been vaccinated. Testing a few unvaccinated young animals, or milk, can show whether the virus is moving in a herd.

BVD can be part of other problems, so your vet may also use the Abortion Investigation Panel for Cattle & Buffalo or the Bovine Respiratory Disease RT-PCR Panel; the exact lists are confirmed when you book. A registered veterinarian interprets every result together with the herd's signs and history.

When to see your vet

See your vet promptly if your herd has more scours, pneumonia, abortions or weak calves than usual, or a calf that keeps falling ill. A young animal with mouth sores and severe diarrhoea needs a vet the same day. Before buying new animals, ask your vet about BVD testing, and ask about vaccination or prevention for your herd.

Testing in Bhopal

Pashupatinath Vet Lab is at C-200, C Sector, Shahpura, Bhopal, and provides free sample collection anywhere in Bhopal. From other districts, samples can come through your local vet, by courier or by bus parcel. The lab coordinates by phone or WhatsApp on +91 88175 01118. Reports are shared on WhatsApp, by e-mail and in My Reports on the website.