16 Sept 2025
Karen Bond BVMS, MRCVS and Jude Roberts BVM&S, CertCHP, PhD, MRCVS review a serious condition that can cause other diseases and how it can be managed
Infectious bovine rhinotracheitis (IBR) caused by bovine herpes virus 1 (BoHV-1) was first described in Great Britain in 1961. It can cause respiratory disease, reproductive disease and conjunctivitis as well as pyrexia and milk drop, leading to significant production losses.
Vaccinations to protect against IBR have been available for many years, with marker vaccines introduced in 2001 and a move towards integrated control through prevention, diagnostic monitoring and vaccination. This article will summarise the diagnostic testing available, vaccination options and how IBR control can be successfully achieved.
Respiratory infection is the most common manifestation of IBR and can vary from mild nasal secretion to acute upper respiratory disease and ultimately to severe and potentially fatal pneumonia. Infection often causes pyrexia and a notable drop in milk yield in adult cattle and there is frequently a conjunctivitis.
Reduced appetite and excessive salivation may occur in some cases due to oropharyngeal and tracheal ulceration, in the worst cases with a severe necrotic tracheitis.
In young calves, the virus may be present as part of the respiratory disease complex, alongside pathogens such as BRSV, PI3 and Mycoplasma bovis. Reproductive disease in adult animals can cause abortion, typically in the second trimester and 3 to 12 weeks following infection. Infectious pustular vulvo-vaginitis (IPVV) is less common, but can be spread through natural service and can cause pain in affected individuals, which deters them from being served. In bulls, infectious pustular balanoposthitis can mean a bull is reluctant to mate, although his libido may still be strong.
One challenge with IBR, similar to other conditions caused by herpes viruses, is that once infected an animal can remain infected for life – this is termed latent infection. The virus survives in neural tissue and can be reactivated and shed following periods of stress, for example, transportation, regrouping within a herd or concurrent disease. Latency can be established when naive animals are exposed to wild virus, even when vaccinated. The disease can cause significant production losses in affected herds.
Two antibody ELISA tests are commonly used in IBR diagnosis and monitoring. The first test targets either the whole virus, or looks for antibodies raised against the gB protein of the virus. These tests will give a positive result in animals infected with wild virus and also those that have been vaccinated with a conventional vaccine. The second test looks for antibodies raised against the gE protein portion of the virus. This test will give a positive result in animals infected with wild virus, but not in animals vaccinated using a gE deleted marker vaccine.
Given the nature of IBR infections, negative bulk milk IBR gE results are likely in herds with less than 10% of milking cows latently infected and where there is little or no virus circulation. Positive bulk milk results will be seen in herds with higher levels of latently infected animals or recent virus circulation. Vaccination will impact gB results so it is important to know the vaccination status of all animals contributing to the bulk tank. Regular testing of bulk milk samples provides useful, cost effective surveillance for dairy herds.
Further proportional sampling of herds can be used to estimate the seroprevalence, or whole herd testing can be undertaken to identify latently infected animals and determine the appropriate control strategy for the herd.
Control of disease includes consideration of herd-level biosecurity alongside use of vaccination in most situations. In some circumstances, it may include culling of infected animals if eradication is to be achieved. Updated this year, the Cattle Health Certification Standards (UK; CHECS) technical document on cattle health schemes describes three IBR programmes – accredited free (AF), vaccinated monitored free (VMF) and an eradication programme. The programmes rely on testing, with or without culling of infected animals, either alone or in conjunction with vaccination. In the AF programme, the installation of double fencing or other boundary to provide a gap of 3m between the herd and any neighbouring cattle is mandatory. A gE deleted marker vaccine can be used in any of the programmes provided the information is recorded and noted on laboratory tests.
What is the primary goal of vaccination?
The vaccination programme needs to provide onset of immunity prior to disease challenge. This, therefore, means the age at which the primary course can begin should be taken in to account, especially if animals are exposed to stock from other units as calves or youngstock.
Cell-mediated immunity is usually rapid in onset and aimed at disease prevention, which is generally achieved through use of a live vaccine within the vaccination programme (Mars, 2001). Refer to the vaccination datasheets for full protocols and vaccine programmes.
A live vaccine administered by the intranasal route is the quickest and most effective way of initiating rapid cell-mediated immunity. This should then be followed up with a second dose to complete the primary course in accordance with the datasheet. Specific vaccines with licensed indications are available for use in this way.
This is a common situation on farms, with repeated tests showing evidence of exposure to wild type infection. Any of the longer-term vaccine protocols should be used in this situation in accordance with the datasheet and taking in to account any specific requirements, for example, prevention of abortion or coadministration with another vaccination.
When vaccination is already being used, but the herd status remains positive for wild virus, three areas should be checked:
Eradicating IBR from a seropositive herd can be challenging. Using an established cattle health scheme, for example, CHECS, can aid all members of farm staff in working towards a common goal. Most eradication programmes will allow the use of vaccination. Testing of individual animals in the herd can help establish whether seropositive animals can be culled as part of an eradication programme, particularly if low numbers of animals are affected.
Vaccination should be used to reduce the impact and spread of disease, using the same aforementioned principles of minimising disease in a seropositive herd.
The uptake of IBR vaccines in the UK is around 33% (AHDB). This has steadily increased in the past few years, but still highlights that a proportion of the population is at risk or unprotected. Several areas need to be considered when designing a vaccination protocol for dairy herds. Protocols should therefore be farm specific and be reviewed regularly, alongside appropriate diagnostic monitoring.
Several vaccine options and combinations are licensed by the VMD that can be used as part of an IBR control programme.
The vaccines should be used in accordance with their datasheet(s), utilising a programme that is designed with the individual requirements of each herd in mind.
IBR is an important endemic disease affecting GB cattle that can have a detrimental impact on productivity and cause significant clinical, as well as subclinical, signs.
Diagnosis can be achieved straightforwardly through performing the appropriate test, depending on the herds’ vaccination status. Control is generally achieved through vaccination and then good biosecurity.
Vaccination protocols should be chosen based on the disease status of the herd and implemented in accordance with the datasheet.
The authors acknowledge they have no conflicts of interest.
Karen Bond took a circuitous route through veterinary medicine after graduation from the University of Glasgow vet school in 2000, including first opinion mixed and farm practice, a farm animal residency, laboratory and field research, knowledge exchange and extension, and now leading the Vet Services Team at NMR (National Milk Records). With a particular interest in infectious diseases of cattle, Karen spends much of her time working with vets to help them best utilise disease testing to make the best management decisions on farm.
Jude Roberts graduated from the University of Edinburgh vet school in 2003. After almost 10 years in predominantly farm practice she moved to work at a pharmaceutical company before joining Map of Ag as a veterinary consultant in 2020. She provides a wide range of consultancy and advice to vets, farmers and within the supply chain and wider industry. Her main interests are in infectious disease control, medicine use and pharmaceuticals and udder health.
