Serology: The defensive line of the turkey flock

Serology is the study of blood serum. More importantly, it is how we can evaluate the level of antibodies in the blood that can fight specific diseases. Anytime an animal encounters a pathogen, either through illness or vaccination, the animal or bird has an immune response. As long as the bird recovers, the bird will realize an increase in antibodies to that pathogen. Although the bird will still be infected with the disease regardless of the antibody level – the higher the antibody levels, the faster the bird will get over the infection and the less shedding of the virus there will be.

Serology is an underutilized tool in the toolbox of turkey health success. Many folks either do not take serology samples or do so at times that decrease the tool’s usefulness. The following are answers to the most common questions about serology.

When should we run serology?
Whenever a test is done, there must be a need for that information, and we have to do something with it.

Serology is the use of blood serum to identify what the bird has been through and survived. It does not work for some other diseases such as HPAI and Cholera, because the birds do not typically live long enough for the body to set up defenses in the blood. Serology works for diseases like Newcastle Disease, Hemorrhagic Enteritis, and Bordetella.

It takes a minimum of seven days to see any response in the blood; usually, the response is detected at ten to fourteen days. Keep that in mind when selecting the appropriate time to bleed the birds. Whatever life stage you are evaluating, bleed the birds seven days after the move as that will offer the most transparent picture of what is in the brood barn. In the face of an unknown disease, bleed during the disease and then again in fourteen days to capture the change in antibodies in the birds’ serum that survived the challenge.

Why is serology useful?
Not only can we use serology to confirm the identity of a viral infection, but it is also a great way to gain the information necessary to tailor a vaccine program to the birds. Serology can also help you identify diseases that are hard to culture or behave abnormally, such as an odd HE infection or anything with an unusual disease curve.

How do we run the serology?
Take twelve blood samples, which allows for some to have poor serum separation. Submit them to the lab of your choice. My personal preference for blood work is South Dakota State University, as they are effective and efficient with the results and have had the quickest turnaround time of any lab I have used. However, the University of MN and the State Lab in Willmar or Iowa State can also help with your needs.

Serology is one of the easiest ways to get a baseline on diseases in the flock, and it is also one of the more affordable. Often by using tailored serology, we can improve livability with that alone. With that in mind, I encourage you to examine the defensive line in your turkey flocks and to loop your veterinarian in to help you evaluate the results. If you need help, I’m always up to look at blood work. Contact me or another Sioux Nation Ag Center employee, and we will do whatever we can to be of service.