Farmers are well aware of the rigorous and ongoing testing of calves for the presence of Bovine Viral Diarrhoea (BVD) since it became a mandatory compliance, as part of the BVD Eradication Programme back in 2013.
Eight years on, we take a look at some of the recent figures regarding calves that have been BVD tested this year, and assess the progress that has been made in trying to eradicate the disease.
Animal Health Ireland (AHI) has revealed that by the end of March 2021 over 1.1 million calves had been tested, representing approximately half of the anticipated calf crop for the year.
Dr. Maria Guelbenzu from AHI has stated that the prevalence of BVD virus positive (BVD+) calves’ births in 2021 continues to decline – with only 0.02% of calves tested in the first quarter of this year being found to be infected with BVDV.
These positive-testing calves were located in 0.31% of breeding herds tested to date.
Looking at the progression made since the eradication programme began, this represents a decrease in calf prevalence of more than thirty-fold since the start of the compulsory phase of the programme in 2013, when 0.66% of calves born were classified as BVD+.
At the end of the first quarter this year, there were 93 persistently affected (PIs) alive in 40 herds.
According to Dr. Guelbenzu, the status of almost all animals in the 83,000 breeding herds in Ireland is now known – with the main exception being a decreasing number of animals born before the start of the compulsory programme in 2013 that have neither been tested nor produced a calf.
At the end of March the number of these animals was approximately 1,500, representing 0.02% of the entire breeding herd population.
The majority of these animals are in beef herds, and the majority are also male. Dr. Guelbenzu went on to state how important it is that these animals are tested in the coming months.
Achieving BVD negative herd status
As part of the BVD testing, herds qualify for negative herd status (NHS) by meeting the following requirements:
- Existence of a negative BVD status for every animal currently in the herd (on the basis of either ‘direct’ or ‘indirect’ results);
- Absence of any animal(s) deemed to be persistently infected with BVD virus from the herd in the 18 months preceding the acquisition of NHS.
According to AHI, by the end of March 2021, around 95% of herds had acquired NHS, with a further 3,600 only being ineligible due to the presence of a small number of untested animals.
From a financial point of view having a NHS will lead to some laboratories that use the RT-PCR test method, offering testing at reduced costs to herds.