HEALTH ▶▶▶
find these bacteria, there is no guarantee that all the viruses have also gone.” To determine the effect of the cleaning and disinfecting pro- cess on viruses, GD has developed its own VIR Check. This test focuses on ‘naked viruses’. As De Wit explains, “‘naked’ sug- gests that you can easily eliminate them by cleaning and dis- infecting the poultry house. However, the opposite is true. Naked viruses are generally very resistant to cleaning and dis- infecting. This is not the case with viruses encased in an enve- lope. These viruses have a layer of fat on the outside which makes them vulnerable to soap and disinfectant”. Examples of naked viruses are reoviruses, the Gumboro virus, rotavirus- es and astroviruses. Unlike bacteria, viruses cannot just be picked up from the floor or wall for examination, so VIR Check uses material in the cloacas of week-old chicks. “When an ani- mal is infected, it quickly produces more virus in just a week’s time. That’s why we carry out our measurements at 6 or 7 days old,” says De Wit.
Field trial GD started a field trial several months ago in cooperation with De Hoop Mengvoeders, AdVee Veterinarians and 22 broiler farms. Its aim was to discover whether the VIR Check score also has a predictive value for the flock’s techni- cal results. The first round results at the 22 participating farms are in, while the second round is still ongoing at most farms, so these results have not yet been disclosed. Flamur Llapash- tica, poultry specialist at De Hoop Mengvoeders, has already noticed that the tests lead to greater awareness. “One poultry farmer’s first round results were all green because he had or- ganised everything very well. In the second round, the result from one of his poultry houses was dark red. It appeared that he had not soaked the poultry house prior to cleaning it be- fore the second round. He had also used a different disinfect- ant in a lower concentration. This confirmed what he already suspected: the score went up rapidly. This system more clearly shows the effect of what you are doing.” “We do not need to convince anyone of the importance of thorough cleaning and disinfection,” AdVee Veterinarians poultry vet Janny Hermans adds. “When the results are insuf- ficient, there may be four or five viruses lying in wait for the new one-day old chicks. That doesn’t mean the chicks will get sick, but controlling these viruses depletes their energy and affects growth.”
No grade
Hermans emphasises that a VIR Check result is not a grade for broiler farmers. “When VIR Check shows red, that does not mean the farmer didn’t do a good job. We can say, however, that the cleaning and disinfecting were not successful. This is often the case because it can be very difficult to thoroughly clean a poultry house. Seams, cracks and floors especially are not easily cleared of pathogens.” The trial results do not trans-
30 ▶ POULTRY WORLD | No. 4, 2020
late into a checklist for cleaning and disinfection that every broiler farmer should use. “It’s not that simple,” says Llapashti- ca. “Every farm is different. The trial with VIR Check does indi- cate however that even small adjustments to the cleaning and disinfecting process can have a major impact.”
Little attention for empty period Llapashtica concludes that VIR Check is an additional aid that can be used to work towards better results. “The empty peri- od deserves more attention at many farms. Every farmer has their own approach and protocol for end of flock, cleaning and disinfecting poultry houses. The VIR Check field trial shows that improvements can be made in many situations. It is often a matter of dotting the i’s and crossing the t’s. Soak- ing poultry houses before spraying is very important, but that can sometimes be overlooked. The length of the empty peri- od is a significant factor as well.” Another goal of the field trial is to investigate whether a good VIR Check score in 6 to 7-day-old chicks has an effect on the technical results and the slaughter process, for example, in terms of better gut health and conformation. These technical and slaughter results have not yet been processed. Llapashtica and Hermans share the view that the field trial confirms that VIR Check is a good tool for broiler farm man- agement. “Over the last few months we have noticed that broiler farmers are very enthusiastic about it,” Hermans com- mented. “Checking cleaning and disinfection with this new test appears to motivate farmers. They are very curious about the results and actively improve their routines to obtain a better score in the next round.” The new test is also useful for farms with slow growing broilers. “The prevailing thought is that pathogens do not play a large part at broiler farms. This is not correct, however. Especially with slow growers, an infection of one-day chicks with reoviruses, for example, can have a major impact on growth.”
VIR Check indicates five viruses
VIR Check is a tool which can be used to ascertain whether the cleaning and dis- infecting process in a poultry house was successful. This test determines the vi- ral pressure in a broiler house. Cloaca swabs provide the basis for the test. The broiler farmer or vet takes swabs from 6 to 7-day-old chicks and transfers them to an FTA card for testing and shipment purposes. VIR Check indicates the pres- ence and amount of five contagious viruses: rotaviruses A and D, chicken astro- virus, aviary nephritis virus 3 and reovirus. VIR Check shows three results: green, orange and red. Green indicates that the cleaning and disinfection process in the poultry house was successful. Orange is the score most broiler farms achieve. Red is a signal that cleaning and disinfection need more attention. VIR Check costs € 89. More info available at:
www.gdanimalhealth.com/lab-services/vir-check
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