'˜Tag and Test' scheme reminder

BVD is a major cause of infertility, abortion and weakly new born calves and predisposes cattle to other diseases along with being a significant cause of on-farm antimicrobial use.

Furthermore, some calves born to infected dams become persistently infected and most of these calves will die before reaching slaughter weight. It is estimated that the virus costs Northern Ireland’s farmers over £20 million each year.

BVD is spread when calves become persistently infected (PI) as a result of their mother being exposed to the virus during the second to fourth month of pregnancy (or if the mother is PI). PI cattle are the main source of infection within herds and the spread of infection between herds.

The key to eradicating the virus is to identify and remove all PI cattle from the national herd. This can be done cost-effectively by testing ear punch samples collected by farmers as part of the official identity tagging process.

The programme works by using specially adapted tags which collects a tissue punch from the calf’s ear during the tagging process. Please note that a new applicator may be required. The cost of the ear tag test is included in the purchase price. Samples must be sent to the laboratory using the envelope supplied with the tag within seven days of the sample being taken. Testing the calf in this way also tests the dam of the calf. Results will be issued by AHWNI using SMS (text) messages and/or letters and will be available within the AHWNI database which can be found at www.animalhealthni.com.

While apparently normal at birth, PI calves usually become ill-thrifty and die before reaching slaughter weight. During this time they remain a source of infection for other cattle, which may lead to infertility and abortions in cows and the birth of further PI calves. It is recommended that PI cattle are culled as soon as possible after being identified. However, in most cases calves will test negative. This indicates that the calf and the dam of the calf are not PIs.

Where BVD virus positive calves are detected, there is the option to confirm them as PI using a blood test or a supplementary tissue tag taken at least 21 days following birth. The dam of the calf will also require a follow-up test which should be arranged with the veterinary practitioner.

UFU and AHWNI would recommend that when purchasing calves born on or after 1st March 2016 you ask for a valid BVD negative test declaration certificate for each animal being purchased. Vendors (or their agents) selling animals can download and print these declarations from the AHWNI website (www.animalhealthni.com).

The BVD control order will require all herd owners to ‘Tag and Test’ all calves born on or after 1st March 2016. This will include those herds that have been testing within the voluntary phase of the BVD.

For those herds that have successfully controlled infection during the voluntary phase, the purpose of this ongoing testing is to ensure, firstly, that infection is not re-introduced into the herd and, secondly, that PI animals are not inadvertently sold onwards as a result.

While legislation will require all herds to test their calves, AHWNI is currently seeking ways to recognise herds that have been testing for three years and have a high probability of being uninfected.

For further information contact your local veterinary practitioner and the AHWNI website (www.animalhealthni.com).