Farmers have been warned that cattle in the Northern Ireland herd will be “increasingly susceptible” to bovine viral diarrhoea (BVD), according to the Animal Health and Welfare NI (AHWNI) group.
The organisation, which promotes improved cattle and sheep health and welfare, said this is primarily due to decreasing levels of natural immunity to BVD.
From tomorrow (Thursday, May 1) new herd restrictions will be applied in Northern Ireland if any BVD positive or inconclusive cattle are kept for seven days. These restrictions will remain in place until three weeks have passed after the last positive or Inconclusive animal has been culled.
AHWNI is now encouraging farmers to think ahead “to future proof herds from infection with the BVD virus”.
The organisation said that some herd owners have chosen to “induce a protective immunity by vaccinating their cattle”.
But it has also disclosed that it is aware of several cases where outbreaks of BVD have occurred due to circulating virus “in vaccinating herds” where vaccination protocols were not carried out in line with the manufacturer’s advice.
In a statement AHWNI said: “BVD vaccines protect the developing foetus from infection with the BVD virus across the placenta.
“It is important to check the individual vaccine data sheets, in general, the vaccination course (either 2 shots 4 weeks apart or a single shot) should be completed three to four weeks before the breeding season.
“Booster vaccinations should be given, again according to the specific instructions. Following the correct protocol will ensure that the best return is being gained from the investment being made in the vaccines.”
Cattle
According to AHWNI, the most common source of infection in new BVD outbreaks in cattle herds has been linked to the introduction of new stock.
But it has highlighted that a larger proportion of current outbreaks are occurring in herds that “have not introduced stock” and where there was no contact with other herds during the susceptible window for infection.
The organisation has indicated that one of the factors behind these outbreaks may have been from “contaminated material” being moved on to farms on equipment or people.
“Requiring high standards of hygiene from visitors to the farm is vital in every herd.
“In breakdown herds, thorough cleaning and disinfection of pens where the positive calves have been present is important to reduce the risk of virus spread,” AHWNI outlined.
Latest BVD statistics in Northern Ireland highlight the impact that herd restrictions have had on the retention of BVD positive calves by farmers.
According to AHWNI, by the end of April, there were only 55 BVD positive animals alive in 34 herds, out of those 28 animals in 22 herds had been retained for more than seven days.
Only two herds had retained BVD positive calves for more than 28 days.
