Vaccines used in the food animal industry not only to help fight animal disease but prevent human illness by lowering the risk that consumers come in contact with contaminated food. Vaccines are weakened or killed organisms, such as a bacteria or virus, that when ingested causes an antibody response to produce future protection against the organism. Many food safety programs in the egg industry require the employment of a vaccination program as one of the many ways to reduce Salmonella Enteritidis (SE) prevalence within the hen and the hen’s environment. Egg producers work with veterinarians to create an ideal vaccination program specific to each farm. Two major types of vaccines are used in the food animal industry today—live and killed vaccines.
Live, or attenuated, vaccines contain weakened forms of the organism or similar organisms that cause the disease. Live vaccination programs are used early in a bird’s life to provide protection during the growing period. The antibodies produced from exposure to live vaccines do not last long, so live vaccines must be given a few times throughout the hen’s life. Live vaccines are usually applied by spraying the vaccine over the chicks soon after they are hatched. The vaccine is then ingested by the chicks as they preen themselves and each other. Live vaccines can also be mixed into the drinking water of older hens and ingested that way as well.
Killed, or inactivated, vaccines provide a much higher and longer level of protection than live vaccines. They are given to birds as their immune systems start to mature, near the end of the growing period. These vaccines stimulate the bird’s immune system to provide circulating antibodies that are intended to last throughout their life. Not only do these antibodies protect the birds, they also have the additional benefit of providing a level of protection to the egg if Salmonella tries to grow. Because of the nature of the vaccine, killed vaccines are administered a little differently than live vaccines. They are injected into each individual bird in a similar method as pet and human vaccinations are administered.
Vaccination of hens is one of the many ways that egg producers protect the health of their hens as and provide the safest product to consumers.