NADIS disease bulletins are written specifically for farmers, to increase awareness of prevalent conditions and promote disease prevention and control, in order to benefit animal health and welfare.

Farmers are advised to discuss their individual farm circumstances with their veterinary surgeon.

Infectious Bovine Rhinotracheitis (IBR)

The NADIS data show that December and January are the peak months for pneumonia. IBR is the most commonly diagnosed of the three viruses causing respiratory disease in cattle

What is IBR?

IBR is caused by the bovine herpes virus. This virus causes three different types of disease: respiratory disease (IBR), venereal disease, and brain disease in calves. The last two are much less common than respiratory disease

Clinical Signs

Ø Nasal discharge (can be clear but is often milky-white)

Ø Conjunctivitis (red eyes)

Ø High temperature

Ø Loss of appetite

Ø Dramatic drops in milk yield may be first sign

Ø Difficulty in breathing and coughing may occur but not consistently

Ø Death can occur in severe cases

Ø Abortion is seen in some animals with clinical signs. (Abortion without clinical signs has not been seen in the UK in contrast to the situation in North America.)

Diagnosis

· On the clinical signs described above. The signs of IBR are very variable. In some outbreaks, little more than a runny nose and red eyes is seen (although drops in milk yield can be large despite the apparently mild disease).

· Unlike PI3 and RSV (the other two main viruses), IBR is commonly seen in adult cattle.

· Your vet can take samples for virus testing from the respiratory tract or conjunctiva

· Blood testing for antibodies can identify infected cattle, particularly if paired samples are taken

· Post mortem examinations are very useful in severe outbreaks, as other disease such as Pasteurella may be involved

· Diagnosis on a herd basis can be made using a combination of blood tests and milk tests. Ask your vet for advice

Treatment

o Antibiotics are useful on preventing and treating infection by bacteria, which often develops after IBR starts.

o Vaccination in the face of an outbreak can be beneficial in reducing its spread

Prevention

1) Biosecurity – Cattle are the main source of the virus, virtually all farms with an IBR problem have bought it in. The main source of the virus is not animals with disease but animals that have recovered from disease, as these cattle still have the virus in their body (they are ‘latently’ infected) You should not buy antibody positive cattle if you are IBR free

2) Vaccination – There are several effective vaccines on the market, discuss with your vet which is the best for you. The main problem with most vaccines is that they produce antibodies which cannot be distinguished from those caused by natural infection. Thus, vaccinated cattle cannot be separated from latently infected cattle. A new vaccine is now available which does not produce the same antibodies as natural infection. This is helpful if you are trying to eliminate rather than control IBR

Richard Laven PhD BVetMed MRCVS