Mandatory annual screening
All breeding herds are required to carry out screening for BVD annually:
- there are currently three acceptable screening methods to choose from
- samples must be submitted to an approved laboratory
- the result will be issued by the laboratory, and will set the herd status to BVD Negative or Not Negative. Results will be reported by the laboratory to the keeper and the Scottish Government
- a vet can change a herd status to BVD Negative provided that they have completed an online BVD training course and have sufficient evidence for negative status
- all keepers of non-breeding herds must test any calves born for BVD virus within 40 days of birth
Since the introduction of the BVD eradication scheme, we have seen the level of exposure to of the disease reduce from 40% of herds having a BVD Not Negative status. Evidence suggests that exposure to BVD in the beef herd is lower than in the dairy herd.
Minimum testing methods
Keepers of breeding cattle herds in Scotland must have their herds screened every year for BVD. There are three testing options available.
You do not have to individually test every animal in the herd to find out if BVD is present. Instead, you can do a screening test that will show if the herd has been exposed to BVD. The result of the screening test will tell you and your vet whether the herd is free of BVD or whether you need to do follow-up testing to find out if there is an active BVD infection in your herd.
Your vet will be able to provide further advice about which method should be used and whether it is appropriate to test for antibodies to BVD or BVD antigen/virus in your case. You must use one of the following methods:
Mandatory annual screening methods for breeding herds
Breeding herds must update their herd status annually using one of the following BVD screening methods:
1. The check-test
Whenever possible for a check test, use option (a) below. Where this is not possible options (b) and (c) should be followed in order. All of these three tests are for antibody, and show if the herd has been exposed to BVD.
Before deciding to do a check test, speak to your vet to identify how many separately managed groups you have in your herd. Your vet will decide how many animals need to be blood tested.
Five calves aged 9 to 18 months
Your vet should take samples of blood from not less than five calves in the age range 9 to 18 months in each separately managed group. If there are fewer than five calves in a group, then test all the calves in the group.
Ten calves aged 6 - 18 months
If any of your sample of calves are aged 6-9 months, then your vet should take a sample of blood from not less than ten calves in the age range 6-18 months in each separately managed group. If there are fewer than ten calves in a group, then test all the calves in the group.
Shetland only: in recognition of the successful eradication of BVD from Shetland, your vet may take blood from not less than five animals in the age range 6-18 months. If there are fewer than five calves in a group, then test all the calves in the group.
Five over 18 months and on the holding since birth
If you have no calves in either of the above age categories, but only then, can you choose to use the following method:
Your vet should take a sample of blood from not less than five animals that have been on the holding since birth in each separately managed group.
0. The dairy check-test - for year-round calving herds
The standard check test (option 1, above) is appropriate for herds that have distinct block calving periods. In dairy herds that calve all year round it can be difficult to ensure that the heifer groups are surveyed properly. To ensure that exposure is detected in these herds more animals must be sampled more frequently.
If you have a dairy herd that calves all year round, your vet should blood sample no less than 10 calves between the ages of 9-18 months, the five youngest and five oldest unvaccinated cattle within each group. Before deciding to do a check test, speak to your vet to identify how many separately managed groups you have in your herd. Your vet will decide how many animals need to be blood tested.
This test must be carried out twice per year, roughly six months apart; more than seven months apart will indicate an expired test result. If you have a dairy herd that calves in distinct seasons you can use the normal check test providing all separate groups are tested.
The number 0 has been allocated for the dairy test in order that the database can recognise that the dairy check-test has been used.
2. Calf screen - test all calves
Individually test all calves born in the herd in the past year for virus by blood or tissue sample. You can test the calves as they are born or all at once. Ear tissue tag testing (explained below) can be a particularly useful way to do this and is the only method, apart from 'method 3: test all animals' (detailed below) that you may do without the assistance of a vet.
Ear tissue tags
Ear tissue sampling tags are designed to take a tissue sample from the ear whilst tagging the animal. The tissue goes into the labelled capsule when the animal is tagged, which you then snap off and send to the laboratory.
If you want to purchase ear tissue sampling tags then contact your usual ear tag supplier. If they do not stock them they should be able to direct you to somewhere that does. If you are sampling calves under 20 days old, you must use an official id tag to take the BVD sample: this minimises the number of tags that are applied to a calf’s ear and reduces typographical errors at the BVD testing laboratory. Management tags can be used to take samples from other cattle (e.g. dead calves, older animals).
3. Whole herd screen - test all animals in the herd
Individually blood or tissue sample all the animals in the herd at the time of sampling. This is a test for virus and has the advantage that all the persistently infected (PI) animals in the herd can be identified and removed. The farmer may choose to tissue tag, in which case a vet does not need to be consulted, however, if they choose to take blood samples a vet will need to be involved. If all the animals are negative for BVD virus this will constitute a negative result for that year.
This testing method is the most expensive option, but it may suit herds where BVD infection is suspected or herds where no other method is entirely suitable.
Important welfare note on ear tagging
If you wish to use tissue sampling tags you should minimise the number of tags applied to each animal. Applying additional ear tags can cause welfare problems for cattle.
If you decide to use tissue sampling tags, make sure you use the correct applicator – some may appear to work with other tags but can apply them too tightly, causing pain and leading to infection.
Testing options summary table:
|No.||Testing option||Dairy/beef||Test for antibody/antigen (virus)|
|0||Dairy with year-round calving
10 animals 9-18 months twice a year
|1a||5 animals between 9-18 months per separately managed group||Either||Antibody|
|1b||10 animals between 6-18 months per separately managed group
Shetland only: test five animals from this age range
|1c||If neither above are possible - 5 animals 18 months+ on holding since birth per separately managed group||Either||Antibody|
|2||Calf screen||Either||Antigen (virus)|
|3||Whole herd screen||Either||Antigen (virus)|
Antibody: tests for exposure to the virus
Antigen (virus): tests for the presence of virus
Mandatory testing methods for breeding herds with a long term 'not negative' status
Breeding herds that have been BVD Not Negative continuously for 15 months must undertake a Compulsory BVD Investigation (CBI) followed by a year of testing all calves. The CBI requires all animals in the herd to have a BVD status with 13 months. As soon as all animals have a BVD status and they are BVD Negative (i.e. any PIs have been removed from the herd) an Approved Vet must sign a CBI Completion Certificate and all calves born in the herd over the next 12 months must be tested for antigen (virus).
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