BVD eradication scheme phase 5 - December 2019: guidance

5. Mandatory Screening Methods

For Breeding Herds

If you currently have a BVD Negative herd status or you have been BVD Not Negative for less than 15 months, you can continue to do a check test for antibodies that will indicate if your herd has been exposed to BVD. You must test a minimum of 5 animals annually, larger herds will need to test more than 5. Your vet will advise you on how frequently and what groups of animals you should test. You have 12 months from your test date to test your animals again. Your vet will be able to provide you with further advice about which of the three methods should be used, and whether it is appropriate to test for BVD antibodies or BVD antigen/virus.

0. The dairy check test - for year-round calving dairy herds.

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 than for the standard check test. If you have a dairy herd that calves all year round, your vet should blood sample no less than ten unvaccinated calves, between the ages of 9-18 months, within each separately managed group. This test must be carried out twice a year six months apart, more than seven months apart will result in an expired herd status. If you have a dairy herd that calves in distinct blocks you can use the standard check test, providing all separately managed groups are tested.

1. Standard check test

The standard check test is appropriate for herds that have distinct calving periods. Whenever possible use option (a) below. Where this is not possible, perhaps as a result of animals leaving the herd before the age of nine months, options (b) and (c) should be followed in order. Before deciding to do a check test, speak to your vet to identify how many groups you have in your herd. Your vet will decide how many animals need to be blood sampled and will also advise on how best to test herds with very low numbers of cattle.

(a) Five calves aged 9-18 months

Take blood samples from no less than five calves in the age range 9-18 months, in each separately managed group (see section 7 for more information). If you have less than five animals in this group, you should discuss with your vet, whether it is appropriate to test under these circumstances. Your vet may check with the lab.

(b) Ten calves aged 6-18 months

If any of your sample of calves are aged 6-9 months, take a sample of blood from not less than ten calves in the age range 6-18 months in each separately managed group. If you have fewer than ten animals in this group, you should discuss with your vet, whether it is appropriate to test under these circumstances. Your vet may check with the lab.

(c) Five homebred animals over 18 months

Only if you have fewer than ten calves aged 6-18 months, and only if your vet advises you, you may choose to use the following method: Take a blood sample from no less than five animals over 18 months that have been on the holding since birth in each separately managed group. If you have less than five animals in this group, you should discuss with your vet whether it is appropriate to test under these circumstances.

Shetland only: in recognition of the successful eradication of BVD from Shetland, you may take blood from no less than five animals in the age range 6-18 months. If you have less than five animals in this group, you should discuss with your vet whether it is appropriate to test under these circumstances.

2. Calf Screen - Test all calves

Individually test all calves born in the herd within the 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 is a useful way to do this, and applying tags early in life helps you to identify and remove PIs promptly.

It is up to the farmer to declare that all calves born within a year have been tested. You must test all calves that are registered as born on your holding. It is also advisable to test any animals that abort a foetus, do not produce a live calf, or die before being registered to ensure these are not persistently infected.

3. Whole herd screen - Test all animals in the herd

This way of screening is the most thorough test and should be considered for herds where a test has resulted in a 'BVD Not Negative' status. Individually blood or tissue sample all the animals on the holding at the same time. This is a virus test and has the advantage that all the PI animals (see section 7 for more information) in the herd can be identified and removed. The farmer may choose to tissue tag every animal, in which case a vet does not need to be consulted. However, if they choose to take blood samples, a vet must be involved. It will constitute a negative result for that year if all the animals are negative for BVD. To maintain your status for the future, you will only need to test animals not included in the initial screen, such as any animals brought in or born. In future testing, you would test all calves and any animal that doesn't have a calf (see section 4 for details of Assumed status).

For Non-Breeding Herds

If you have a non-breeding herd, you only need to test for BVD whenever a calf is born into the herd. You must test these animals within the first 40 days of life. If you are testing a calf under 20 days old, you should use an official ID tag that takes a tissue sample - these are available from most ear tag suppliers. The sample should be sent to an approved laboratory and tested for virus. You must not move these animals until they have been tested and shown to be BVD Negative.