Establishing the BVD status profile of your herd
The aim of the NI BVD Programme is to eradicate BVD, so that production costs due to BVD are eliminated leading to increased resilience to other diseases and therefore fewer losses to conditions exacerbated by BVD. As we aim for eradication, the status of every bovine animal counts and the removal of every BVD Persistently Infected (PI) animal is essential.
Eradication can be achieved through farmers taking two steps: firstly, by testing their cattle for BVD (as untested cattle may be a potential reservoir of virus); and secondly, by acting on veterinary advice to cull BVD PI cattle. Cattle that obtain a BVD positive result should either be retested (3 weeks after the initial test) or culled at the earliest opportunity. Failure to remove PI cattle means that the virus has the potential to infect pregnant females in the vicinity; such infection is likely to result in BVD, and its effects on animal health and survival, persisting into the next season.
From the disease control perspective, it is industry’s aim that every animal in the NI cattle herd should have a direct Negative (BVDN) or indirect Negative (INDINEG) status. Farmers can look at their APHIS herd list to check the BVD profile of their herd.
There are currently over 15,000 homebred animals of unknown BVD status (BVDU), born on or after 1st March 2016, that should be tested as soon as possible using a supplementary tag or a blood sample taken by a private vet. These untested animals may not be moved from a holding until they are sampled and a negative test result for the samples obtained from an approved laboratory. AHWNI can carry out checks on imported (BVDU) animals against ROI BVD status data, where an approved laboratory has been used, to establish whether a negative BVD status can be uploaded to APHIS for these animals without the need to carry out further tests.
Cattle born before 1st March 2016 that do not have a known BVD status are worth checking (there are over 25,000 animals in this category) - a small number of samples may be required to complete the herd picture – by testing either a supplementary tag or a blood sample taken by your vet. Over 350,000 cows have an INDINEG status on APHIS at present – many of these were born before the start of the compulsory programme and have been assigned an INDINEG status as their calves have had a BVD Negative result.
For those farms that have a full BVD Negative profile and have not experienced BVD infection within the last year, the focus must continue to be to safeguard the herd. No calves born into a herd that is of a low risk status should be PI, unless the BVD virus has been introduced, for example through the purchase of pregnant animals carrying unborn PI calves, contacts with neighbouring stock or by infected material being carried on to the premises by people or on equipment.
A herd with all Negative status animals has achieved an indicator of health that is worth protecting. In order to maintain a BVD Negative herd profile, it is essential that biosecurity practices are taken seriously. AHWNI encourages all herdowners to speak with their vet to assess the risk of infection getting into their herd and what measures they can take to prevent this from happening.