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Infectious Bovine Rhinotracheitis

Infectious Bovine Rhinotracheitis

We’ve recently had a spate of Infectious Bovine Rhinotracheitis (IBR) cases, often in herds that have been infected for years. For this reason, here’s a refresher on this important disease.

IBR is caused by a herpes virus and presents itself in 3 ways: respiratory disease, venereal disease and neurological disease in calves. The most important presentation for us is the respiratory disease and outbreaks in adult cattle can result in severe production losses (growth and milk), abortion and mortality.

Clinical signs include:

  • Fever (up to 107oF/42oC)
  • Lethargy and loss of appetite
  • Conjunctivitis (red eyes)
  • Nasal discharge (clear to green)
  • Severe milk drop
  • Infertility and abortion
  • Coughing and struggling to breathe

 

The disease is often complicated by a secondary bacterial pneumonia.

Once infected, an animal remains infected for life as the virus walls itself away from the immune system. Any stress to the cow causes a check to its immune system and allows the virus to multiply and starts to be shed by the cow.

If your herd is chronically affected by IBR this may be of no consequence but we often see clinical disease in naïve heifers just brought into the milking herd.

IBR can be diagnosed from the clinical signs and history in the herd. This can then be confirmed with nasal and conjunctival (eyelid) swabs interpreted alongside milk and blood samples.

There is no specific treatment for IBR as it is a virus. Treatment of individual cases involves covering the animals with antibiotics to prevent secondary infection (Draxxin® in non-milkers, Excenel® in milking cows). The animal should be given an anti-inflammatory to drop the fever, such as Finadyne® or Ketofen®.

If an outbreak is occurring at-risk animals can be vaccinated with IBR live vaccine. This can be administered most effectively up the nose or in the muscle and animals from 2 weeks old can be treated. 

If you have IBR endemic within your herd vaccinating your cows with an inactivated vaccine (e.g. Rispoval IBR inactivated®) will reduce the amount of shedding by infected animals. This will then prevent the spread of the virus to naïve animals.

Vaccination does not eradicate disease from the herd, so followers and young stock should also be vaccinated before entering the herd.

Biosecurity should always be considered when buying in animals. Infection status of bought in stock should be ascertained before purchase. Animals positive to IBR should not be introduced to a naïve herd, just as naïve animals should not be introduced to an infected herd.

If you’ve any further questions, please feel free to contact us at the practice.