25-04-2025
Number of BVD positive herds up nearly 20% year on year
The number of Bovine Viral Diarrhoea (BVD) positive herds has increased by nearly 20% since this time last year – increasing to 113 positive herds in week 17 of 2025 from 92 positive herds in the same period last year.
According to Animal Health Ireland's (AHI) latest BVD free programme results the number of BVD positive calves at week 17 of 2025 was recorded at 367 head compared to 189 in the same period of 2024.
The number of BVD positive calves represents an 85% increase from the same period in 2024.
AHI told Agriland that 'it has been a disappointment to see a rise in positive BVD test results in 2025 to date when compared to last year.'
Out of the 1,472,699 calves that have been tested so far in 2025, 99.25% of those calves tested have come back as negative results, three returned as inconclusive, and 10,561 (0.72%) came back as empty.
BVD
Agriland had asked AHI if the rise in BVD positive calves and the number of herds affected was a concern for their programme.
In response AHI's programme manager for BVD and IBR, Maria Guelbenzu said: 'Significant progress has been made by the Irish BVD Eradication programme.
'Last year alone saw a 31% reduction in affected animals and a 24% reduction in affected herds compared with 2023.'
Guelbenzu added that 'While it is early in the year to assess the impact of this increase and whether it will sustain, Animal Health Ireland is currently performing analyses to assess the reasons behind the increase and remains in constant contact with the Department of Agriculture on the issue.'
The programme manager said that one of the reasons for the rise in cases from last year is the occurrence of large outbreaks in dairy herds.
Guelbenzu added: 'While investigations into the source of these particular outbreaks are ongoing, we believe several factors may be contributing to this including a decline in herd immunity on farms.'
She also said that while the number of affected herds is 'still small' – 113 out of 42,279 of herds tested to date this year – the effect on those herds can be substantial.
Guelbenzu has urged farmers 'to be vigilant, sample and test their calves promptly, keep untested animals separate from pregnant animals and act quickly if a positive result is obtained'.
For farmers who are in close proximity to positive BVD cases, Guelbenzu also advised them to 'review their biosecurity protocols and consider additional precautions, including vaccination. Programme maps are updated monthly and available in AHI's website.'
She added: 'Irish farmers have put in an enormous effort to achieve freedom from the disease and it is crucial that we continue to pursue the collective goal of becoming BVD free.'
Preventing the spread
The longer a BVD-positive (BVD+) calf remains on the farm, the greater the risk of infection spreading, both within the herd and to neighbouring farms.
Farmers should follow the following tips:
Tag all newborn calves as soon as possible after birth. Ensure that calves are dry before tagging to minimise the occurrence of 'empty' tags (tags without tissue samples);
Isolate newborn calves from pregnant cows and maintain strict biosecurity measures until a negative test result is confirmed;
Farmers participating in the National Genotyping Programme will receive double tissue tags. Note that BVD sampling under this scheme requires a different set of taggers. BVD sample bottles/vials and lab envelopes are white, while DNA sample bottles/vials and lab envelopes are pink. Ensure each sample type is sent to the correct laboratory.
Farmers in proximity to positive BVD cases should review their biosecurity protocols and consider additional precautions, including vaccination.
Quarantining new cattle entering a yard is also crucial as is ensuring that people entering the yard dip their boots in disinfectant, especially with an AI technician frequenting a yard during the breeding season.
