ERADICATING bovine virus diarrhoea (BVD) from your farm will not only have substantial health benefits for your livestock, it will also result in a healthier bank balance at the end of the year.

According the the National Animal Disease Information Service (NADIS) in its latest 'health bulletin' for Scotland's livestock farmers, dairy farmers would be better off by almost £16,000.

For specialist beef farmers, the bottom line could be £2400 to the good and a similar amount if your are a lowground beef and sheep enterprise.

That's because of the economic implications caused by the disease, which include reduced fertility, poorer production and increased susceptibility to other infections, especially in young calves.

The cause:

BVD is caused by a virus and the main transmission route is by direct contact with cattle persistently infected with BVD virus.

It needs only one persistently infected animal to be introduced to a susceptible herd to cause very significant financial losses and the stats show that 90% of UK herds have had exposure to bovine virus diarrhoea virus (BVDv).

Clinical signs:

Non-pregnant cattle:

- Cattle exposed to BVD virus may show few clinical signs producing protective antibodies within three to four weeks.

- BVD virus infection may temporarily lower immunity to other infectious diseases particularly in young calves.

Early pregnancy:

BVD virus during early pregnancy may cause:

- Embryonic death and return to oestrus;

- Foetal death/abortion;

- Mummification of the foetus;

- Birth defects of the nervous system and eyes;

- Weak/premature calves;

- Live persistently-infected calves which appear normal.

Importance of persistently-infected calves:

- Infection of the foetus less than 110-120days of gestation may lead to the birth of a live calf persistently infected (PI) with BVD virus.

- PI calves are born viraemic and remain so, acting as potent sources of BVDV infection to in-contact cattle.

- Growth rate of PI calves is often much less than normal calves.

Mucosal disease occurs when persistently infected animals become superinfected with cytopathic BVD virus. The cytopathic BVD virus arises from changes in the BVD virus within the PI animal. Most cases of mucosal disease occur in six to 12 month-old calves.

Clinical signs of mucosal disease:

- Sudden onset dullness

- Salivation

- Fever

- Anorexia

- Ulcers appear in the mouth and on the muzzle;

- Purulent discharges from the eyes and nostrils;

- Profuse diarrhoea with shreds of gut mucosa/blood present during the terminal stages. Rapid weight loss follows;

- Death within five-10 days.

Diagnosis for acute BVD:

- Paired blood samples three to four weeks apart to demonstrate rising antibody levels to this virus

Persistent infection:

- Virus detected in ear punch sample

- Two positive samples taken three to four weeks apart confirm persistent virus infection.


For acute BVD - treat all secondary bacterial infections that occur. For persistent infection - PI animals should be disposed of immediately as they act as a source of BVD infection for the rest of the herd.

Prevention and control:

BVD will be an integral component of the veterinary herd health plan and farmers must up their game with biosecurity, vaccination and eradication methods.


- Maintain a closed disease-free herd;

- Test all introduced stock and quarantine until results known;

- Maintain double ring perimeter fencing;

- Do not use common grazing areas.


- Two doses three to four weeks apart before first service

- Booster vaccination at 12 months' intervals


- It is possible following whole herd blood testing and elimination of all PI carrier animals

The welfare implications of the disease are considerable and cattle with mucosal disease must be euthanased immediately upon diagnosis. Calves born with eye and brain defects due to virus infection during their development must also be euthanased.