Bovine viral diarrhoea

This guidance is for Scotland

Bovine viral diarrhoea (BVD) can have very varied symptoms from inapparent infection to severe enteritis, abortion and death. It can have substantial impact on the profitability of farms. This highly contagious disease has been estimated to cost between £13 and £31 per cow in Great Britain. It impacts animal welfare within affected herds and reduces farm productivity and profitability.

Control and prevention can be achieved through improved biosecurity and vaccination.

Following pressure from the agricultural industry, the Scottish Government agreed to introduce a staged programme of increasing control measures to attempt to eradicate the disease in Scotland.

Clinical signs

Clinical signs can vary greatly, such as a bout of diarrhoea or pneumonia (often in a group of animals), or an increase in abortions / stillbirths and a decrease in fertility.

Calves contracting the disease while still in the womb can be born as 'persistently infected' animals (PIs*). Such animals continue to excrete the virus throughout their lives and are therefore the greatest risk of spread of infection. These animals, as well as failing to thrive, tend to have impaired immunity, making them more susceptible to other diseases. They are likely to die before reaching maturity. Cattle infected after birth can recover from BVD, but do suffer from a reduced ability to fight other infectious diseases.

[*For ease of reference, all animals that are BVD positive are referred to in this guide as PIs.]

BVD is spread via contact with infected cattle, particularly PIs. A thorough BVD testing regime, movement restrictions and good biosecurity controls are required to eradicate this disease.

BVD testing requirements

On 1 December 2019, Scotland began phase 5 of the BVD eradication scheme, with the aim of protecting 'BVD negative' herds at all costs. Phase 5 places further responsibilities on keepers of 'BVD positive' animals and 'BVD not negative' herds, which have been 'not negative' for more than 15 months.

Every year keepers of a breeding herd of cattle or a breeding bovine animal must take, or arrange to be taken, a sample from a set number of animals (this varies according to farm set-up) for BVD. Dairy herds must be 'check tested' twice a year if they calve all year round. The samples should not be from animals that have previously been tested and found to be negative, or dams of such animals (such dams are assumed to be negative).

A breeding herd is defined in the Bovine Viral Diarrhoea (Scotland) Order 2019 as "a group of two or more bovine animals in which breeding, whether by natural, assisted or artificial means, is intended by its keeper to take place and no steps are taken to prevent or minimise the chances of such breeding".

The sample (which can be either blood or a part of the ear taken using a special ear tag) must be submitted to an approved laboratory for testing. Only a vet can take and submit a blood sample, but farmers can take and submit a sample using an appropriate ear tag. An official tag (primary or secondary) must be used when tissue tagging calves under 20 days old.

Within five days, the laboratory must notify the Animal and Plant Health Agency (APHA) and the keeper of the results - via ScotEID - clearly stating whether the result is 'negative' or 'not negative' for exposure to BVD virus, or confirms the presence of the BVD virus.

A result of 'not negative' does not necessarily mean that there is BVD in the herd; it simply means that an animal / animals have at some point been exposed to the disease. Further advice should be sought from your vet.

Where a calf is born to an animal that was not intended to be bred from (that is, not a breeding bovine or in a breeding herd) a sample must be taken within 40 days of birth and submitted for testing. The calf must have an individual BVD negative status before leaving the herd.

Further guidance on the testing regime can be found on the Scottish Government website.

Herd status and movement restrictions

The herd status has to be updated each year and is dependent on the most recent test results. The herd status can be 'negative' or 'not negative'. The PI locator on ScotEID displays the CPH numbers of all herds with BVD-positive animals that have been in a herd for more than 40 days.

Animals from herds that are classified as 'not negative' are not permitted to move from the holding they are on, except in one or more of the following circumstances:

• they are individually tested and found to be negative
• the movement is under a licence issued by a veterinary inspector or APHA
• they move direct (not via a market) to a slaughterhouse

A breeding herd that has not been tested is classified as 'not negative' and the movement restrictions above apply. Similarly, if a breeding herd / animal is kept on the same holding as a breeding herd / bovine that has not been tested, it is also classified as 'not negative'.

Where a keeper is notified that their herd is 'not negative' and another herd is kept on the same holding, they must notify the other keeper(s) of the test result, and of any subsequent change in status, within seven days. Where a breeding animal is to be moved off a holding, other than for slaughter, the keeper must notify the new keeper (even if only a temporary keeper) or market operator of the BVD status of the animal / herd.

Bovines confirmed BVD positive must not be moved off the holding other than direct to a slaughterhouse or under licence; nor may cattle move on to the holding, except under licence from APHA. Movement restrictions may only be lifted once the positive animal is removed to slaughter or the animal has been retested and confirmed to be no longer BVD positive. The retest of any positive animal can only be undertaken by a veterinary surgeon.

Risky animals

Cattle without an individual BVD status are termed 'risky' animals. These animals fall into one of the following categories:

• born into non-breeding herds in Scotland
• brought in from outside Scotland
• come from BVD 'not negative' herds in Scotland

On arrival into the breeding herd, these animals must be tested for BVD within 40 days (unless moved directly to slaughter within 40 days). 'Risky' animals cannot leave the herd without an individual BVD-negative or assumed-negative status.

Compulsory BVD investigation

Herds that have tested BVD 'not negative' for more than 15 months, must undergo a compulsory BVD investigation (CBI). A CBI will require the keeper to test all animals within the herd to obtain a BVD-negative or assumed-negative status.

If a BVD-positive bovine is found, movement restrictions as outlined above will apply. If the BVD-positive animal remains on the holding for more than 40 days, the keeper's CPH number will be added to the PI locator list on ScotEID until the animal is removed to slaughter or tests BVD negative.

Once all the animals test BVD negative, the CBI is complete. Keepers must continue to test all calves born into the herd for a further 12 months.

Minimising risk

All BVD-positive animals must be housed indoors - consistent with good practice and separately to other cattle on the holding - to minimise the risk as far as possible of transmitting the virus.

Where there is only one BVD-positive bovine, the keeper must ensure that the PI is housed with the minimum number of other bovine animals necessary in order to protect the welfare of each animal. This is regardless of individual animals' BVD status.

Other means of reducing risk include:

• check the BVD status of any animals you bring on to your holding. This can be done on the ScotEID website (email help@scoteid.com, tel: 0300 244 9823)
• avoid buying in pregnant animals, as calves that contract BVD in the womb can become PIs for BVD. Also avoid taking pregnant animals to shows
• avoid nose-to-nose contact with cattle from neighbouring holdings
• vaccination may be an option, but this should be discussed with your vet

Can people catch the disease?

BVD is not known to affect humans, but good hygiene procedures should always be followed after contact with livestock.

Could it affect the food I eat?

No, it does not affect the food we eat and it cannot be contracted by consuming beef products.

Further information

More detailed guidance on BVD (including specific guidance on phase 5) is available on the Scottish Government website.

Trading Standards

For more information on the work of Trading Standards services - and the possible consequences of not abiding by the law - please see 'Trading Standards: powers, enforcement and penalties'.

In this update

No major changes.

Last reviewed / updated: September 2024