BVD outbreak resulted in loss of over three-quarters of calves
Paul, who farms at Donooney, Adamstown, experienced the BVD nightmare in spring 2014. He calved 52 cows in 2013. All calves were tissue-tagged and were negative for BVD. He was very conscious of disease prevention.
Cows were vaccinated against leptospirosis and salmonellosis. They were also vaccinated pre-calving to protect against scour in calves and he also had an IBR vaccination strategy in place.
He had previously operated a closed herd and therefore did not feel the need to vaccinate against BVD.
In summer 2013, he bought in eight heifers. And that is when the BVD horror story began.
“I noticed one of the heifers was not thriving as well as the rest, but I had no reason to suspect there was anything seriously wrong with her,” said Paul.
In September 2013, 53 animals were scanned in-calf, including the bought-in heifer. But everything changed when the cows started to calve in 2014. Paul tells the gruesome story.
“It was an absolute nightmare. Thirteen cows lost their calves before calving, including the bought-in heifer who aborted after about four months in-calf. Of the 40 calves that were born, we finished up with 12 that lived.
“Some were born dead or died immediately after birth. Over 20 lived, but got pneumonia and scour and anything else you could think of. With a lot of help from my vet Tomás O’Shea of Moyne Veterinary Clinic, we tried to keep them alive, but they failed to respond to all treatments. They were in a shocking state.
“In the end, I agreed with Tomás that the only option was to put them down. Every single one of the 28 that died or were put down was a PI.”
When the first signs of the impending disaster began to appear, Tomás O’Shea blood-tested all breeding stock. One – the suspect bought-in heifer that had aborted – tested as a PI. She was immediately removed from the farm.
The cows that did not produce a calf were sold. All remaining breeding stock were given a primary and booster vaccination with Bovilis BVD in advance of the 2014 breeding season. Annual BVD vaccination is now a rigid part of Paul Barden’s animal health programme.
The number of cows in the herd dropped to below 40 in 2015. Paul bought in weanlings in order to “keep up numbers”. He has gradually increased the size of the suckler herd and will calve around 45 cows this year – a mixture of Salers and Limousin – with the progeny being reared to forward stores or beef.
Animals can now be given a combined booster vaccination against BVD and Infectious Bovine Rhinotracheitis (IBR). This means that Bovilis BVD and Bovilis IBR Marker Live can be mixed together and given in one single 2ml intramuscular injection.
The combined vaccine should be used as a booster dose in cattle from 15 months old, helping to simplify vaccination against two of the most important and debilitating diseases.
Bovilis BVD and Bovilis IBR Marker Live should be used separately when administering the primary vaccine against BVD and IBR.
Talk to your vet about best practice in administering the combined booster vaccine.
“Vaccination, combined with identification and removal of PIs, good bio-security and ongoing monitoring, are crucial in controlling BVD,” said veterinary adviser Joanne Cregg.
“Two injections of Bovilis BVD, given four weeks apart, are needed in non-vaccinated cows and heifers. The second shot should be given no later than four weeks before breeding.
“All vaccinated animals should then get their annual booster vaccination at least four weeks before breeding,” said Joanne, who is veterinary adviser with MSD Animal Health.
When administered at the correct time, Bovilis BVD is licensed to provide protection of the foetus during the risk period.
Leptavoid H, a vaccine for controlling leptospirosis, can be given at the same time as Bovilis BVD.
Veterinary practitioner Tomás O’Shea of Moyne Veterinary Clinic in Enniscorthy said Paul Barden’s experience is a classic example of what can happen when a BVD-positive animal is introduced to a closed naïve herd.
“This was the first time in many years that Paul bought in. Once the PI animal was introduced, the herd was just ripe for infection,” said Tomás.
“We are still seeing plenty of PIs, mainly because farmers have stopped vaccinating due to the mistaken belief that the absence of PIs means there is no risk of infection.
“I continually stress to farmers that even when a PI animal is removed, this does not mean that the herd is free of BVD. Equally, where no PIs are identified and where a closed policy is operated, there is still a constant risk of infection from neighbouring herds or on equipment and people,” he said.
He gave the example of a dairy farmer client who operated a strict biosecurity policy and was regularly monitoring for BVD. Animals from a neighbouring herd broke into heifers he was grazing on an outfarm. The animals were removed in less than four hours but the damage was done.
“The result was poor fertility, abortions and a number of PI calves born. It highlights how rapidly a naïve herd can be infected with this disease,” he said.
“Because of the multitude of methods by which the BVD virus is transmitted, annual vaccination against BVD is an absolute necessity on every farm,” he advised.
“I know of farmers who stopped vaccinating because they thought the risk of infection had disappeared. Many are now vaccinating again because of the recurrence of PIs or stories they have heard from neighbours about a fresh outbreak. There really is no alternative to vaccination until we rid the country of this serious disease,” he stressed.
He said the name and shame policy, combined with the improved compensation and the requirement for a veterinary investigation when a PI animal has been identified, has led to a big improvement in the rate of immediate removal of PI calves from herds.