Empty BVD tags double on last year

Concern is growing about the escalating number of BVD tissue tags that are being classified as empty.

This year up to 8 March, over 6,500 tissue tags presented for BVD testing have been evaluated as empty, necessitating a retest. A replacement tag must be ordered, the tissue sample collected when tagging and posted to a laboratory.

The costs incurred of about €4/head are dwarfed by the cost of maintaining a calf until the second sample is tested, should the animal turn out to be persistently infected (PI).

Almost 700,000 samples have been delivered to the 11 testing centres so far this year. That’s a 30,000 reduction (4%) on last year, just another indicator of slower calving, particularly in the dairy herd, this year to date.

Of these, 6,557, just shy of 1% of samples, are empty.

Last year the corresponding figure at this stage was 3,444 – half the proportion of empty sample tags.

Since last year, a number of changes have occurred.

Mullinahone had previously been the only tag provider. Its Eurotag, the only tag type before this year, has changed since last year.

In addition, two new tag providers, Cormac Tagging and Datamars, have introduced the Caisley FLEXOPLUS and the Typifix, respectively. Furthermore, testing labs have invested in new equipment to test the new tags.

Detailed analysis

The IFA is seeking a detailed analysis of the current spike in the empty samples occurring.

“This issue must be addressed due to the costs being imposed on farmers,” said animal health chair Bert Stewart. “It’s vital that whatever has contributed to this unwelcome trend is discovered and addressed.”

In total, 735 persistently infected (PI) calves have been identified this year so far. PI numbers have fallen sharply each year since compulsory testing began in 2013.

The 735 PIs represent 0.11% of calves tested, compared to a PI incidence of 0.77% from 2013. Some 483 herds have so far recorded a PI case – a little over 1%.

Just 12 herds have retained a PI for more than five weeks after the first test in 2017.

This compares favourably with the 72 herds who had retained an animal for more than the seven-week limit last year.

It seems the combination of carrot (extended payments for early delivery of PI animals) and stick (restriction of herds containing PI animals) is having an effect.