This article is presented to you by the Poultry Health Services veterinary team
Infectious Bronchitis (IBV) is a viral disease that causes a drop in egg production and egg shell quality. This is a problem in table egg layers, as well as in broiler breeders. Although there are many other factors that can cause the above-mentioned problems in laying flocks, (ie: feed quality, low Ca levels, and poor barn environment, to name a few), IBV is always suspected and producers request that this disease be ruled out. This is, of course, a prudent approach and we always encourage dead birds and blood samples to be submitted to the diagnostics lab.
In this article, we are going to briefly update you about the problems Eastern Canada, primarily Western Ontario and Quebec, have been facing in the last few years with new strains of IBV.
Here are the main signs seen in the affected flocks:
Laying hens may cough and sneeze for 10-14 days with feed consumption and weight gain reduced. Egg production may drop by as much as 70% and mortality can reach 5%. If other pathogens are involved like E coli or Mycoplasma, mortality can be higher. This virus is present in the respiratory discharge and feces of infected hens and is spread from flock to floc or between farms through air, ingestion of contaminated water or feed, manure spread by people (on their hands, clothes or boots) and equipment.
Infectious Bronchitis is a single disease but is caused by different strains or types of the virus. This is very important to understand, as the vaccines we use only protects against a field challenge from a virus of the same type. For example, many vaccines have so called Massachusetts strain and can protect your birds only against the Massachusetts field strain (please check the label carefully next time you handle a live IBV vaccine). Unfortunately, in 2014 a strain of IBV called 4/91 affected many flocks in Ontario and during 2015/2016 a so-called California and DMV (Delmarva) strains were detected. As mentioned above, these strains caused severe losses in table layer flocks; also affecting broiler breeders and broiler flocks. Producers are faced with a significant problem as current vaccines (live or killed) do not fully protect against these viruses. This said, producers need to continue to vaccinate with the available vaccines. This brings the importance of biosecurity to the forefront in the protection of our livelihood.
To the best of our knowledge, we have not seen these viruses affecting any flocks in Alberta. However, there is no time for complacency and we ask all EFA producers to strengthen the biosecurity at their farms; submitting birds and blood samples for diagnostics and vaccinating their flocks regularly.
The Infectious Bronchitis vaccine is very fragile and can be destroyed easily if not properly handled. In our next article we will focus on proper vaccination techniques and in the meantime, please consult with your veterinarian and field service representatives if you have any concerns.