NWhen a concerned West Flemish pig farmer reported a sudden increase in preterm births in the young sows on his farm to his company veterinarian, the latter immediately jumped into action. He confirmed his diagnosis of PRRSV through examinations and adjusted the vaccination schedule for PRRS. However, the situation escalated and the problem spread to rejects and preterm births in sows of all parities, plus a decline in the number of weaned piglets. This was the signal for them to call in external help. For example, Caroline Bonckaert, regional veterinarian at DGZ, came to the company.
Vaccination is a tool, not a panacea
The first thing Caroline did was discuss the whole situation in detail with the farmer and his vet. “I knew that the vaccination schedule had already been adjusted by the company veterinarian. That is why we went through the procedures together for correct storage and administration of the vaccine. It was clear that the farmer carries out the PRRSV vaccination correctly and with precision, so I couldn’t identify areas for improvement,” says Caroline.
“But there are so many other things involved in getting PRRS under control on a farm. Vaccination is after all an aid in the approach to PRRSV on the farm, but also not a panacea. That is why we continued to work on identifying and tackling other risk factors as well.”
Is the search bear protected?
There is one search bear on the farm. This search bear is, as is often the case, a bear that has been ‘forgotten’ to castrate and which goes through the route like a meat pig. Since the piglets on this farm are not vaccinated against PRRSV, there is no certainty about the protection of the animals against PRRSV infection with the finisher pigs – and therefore also with the search boar.
When inquiring about the age of the search boar, it emerged that a new search boar had recently been introduced from the finisher barn to the sow barn and that no quarantine or adaptation phase had preceded this. “This is a pain point for many companies with potentially major consequences. The search boar is removed from the finisher barn without additional measures. People are often not aware of it, but at that time this bear could pose a great risk not only for spreading PRRSV, but also other diseases,” said Caroline.
Caroline Bonckaert therefore advised that the search boar should be vaccinated immediately with the group vaccination of the sows and that, when a search boar is introduced next, to isolate and vaccinate the animal, not only against PRRSV, but also against other relevant pathogens.
Adjust the way of working
The pig farmer of this company grows his gilts himself and does not buy anything. This is definitely a plus when it comes to PRRS control, as PRRSV introduction is often done through live animal purchase. He keeps the gilts in a separate section, separate from the finishers. Every 4 weeks a new selection of future sows comes into the rearing pen and at the age of 5.5 months they are vaccinated once. The equipment of the rearing department is shared with the fattening pig departments, as they reside under the same roof.
“However, this way of working entails a number of risks,” says Caroline. “The rearing house is almost never empty, which means that it is not possible to thoroughly clean and disinfect. And by sharing the material across the different departments, PRRSV can spread between finishers and rearing gilts. In addition, the single vaccination can create subgroups of rearing gilts, each with a different PRRSV status.” The advice was to adapt the working method in the rearing barn and to create uniform protection for the gilts.
Evolution towards negative results
To monitor the situation in a simple way, processing fluids (castration fluid) examined for the presence of PRRSV by means of PCR. Over a period of several months a clear evolution was seen from a strong presence of PRRSV to negative results. This result also corresponded with what the farmer saw in the barn: there was more rest, there were fewer premature births and fewer sick animals.
“It took some searching, but by putting our heads together, some important action points came to the fore,” says the pig farmer. “The fact that Caroline Bonckaert was able to view the entire situation with an external, fresh perspective turned out to be an absolute added value. Thanks to the tips she gave us, I am convinced that from now on I will finally be able to control PRRS together with my company veterinarian.”
Charlotte Brossé, DGZ
All information about PRRS can be found on the website www.sdrp-prrs.be.