April 16, 2009
Don’t risk your horse’s health: Listen to this vet’s advice to get the most out of your vaccinations.
By The American Quarter Horse Journal horse health columnist Dr. Tom Lenz
Vaccines are an important part of any preventive health program, but there are a number of factors that we need to consider if we are going to ensure that our horses develop the best possible immune response and disease protection.
The first factor is the type of vaccine used, as well as the antigens in the vaccine. Antigens are the portion of the vaccine that stimulates the horse’s immune system to produce antibodies and specific white blood cells that attack the disease if it ever enters the horse’s body. Most vaccines contain multiple antigens.
Common combinations are tetanus and sleeping sickness (eastern and western encephalomyelitis) or flu (influenza virus) and rhino (equine herpesvirus). Currently, West Nile virus can also be found in combination with these antigens.
Dr. Lenz brings you up to date on West Nile virus and other common conditions in Disc 1 of AQHA’s “Your Horse’s Health” DVD set. Along with Dr. Kenton Morgan, Dr. Lenz gives you important health information that every horse owner needs to know.
When selecting a vaccine for your horse, make sure it contains the specific disease antigens you want to protect your horse against. You may want to choose a vaccine from AQHA’s official vaccination sponsor, Fort Dodge. Your local American Association of Equine Practitioners veterinarian is the best source of information on the specific diseases you should immunize your horse against in your part of the country.
The second factor to consider is the care and handling of the vaccine. Vaccines must be maintained at the appropriate temperature from the time they leave the manufacturer to the time of administration. Most vaccines should be stored in the dark and kept refrigerated at temperatures between 35 degrees and 45 degrees F.
Avoid freezing, and be sure to shake the vaccine well before using it to ensure uniform suspension. Exposure to heat, excessive light or freezing can damage vaccines and make them useless. Damaged vaccines can also be responsible for an increase in injection-site reactions.
The third factor to be considered is the individual animal and its ability to mount a good immune response to the vaccine. Individual horse factors can include the presence of maternal antibodies in foals, concurrent disease, poor nutritional status and stress, just to name a few. Maternal antibodies that are consumed by foals with the mare’s colostrum will block vaccines. We don’t recommend vaccinating foals before they are 4 to 6 months of age.
Since your individual horse will respond differently to vaccinations based on their current health condition, it is important to be knowledgeable about nutrition and other aspects of horse care. In AQHA’s “Your Horse’s Health” DVD set, Dr. Lenz gives a wealth of information about care for your horse, especially foal care and mare care.
Geriatric horses have weaker immune systems and might not be able to respond to vaccination as well as younger horses. Without a doubt, one of the biggest factors in preventing a good immune response is stress. Stress can alter the horse’s immune system and increase susceptibility to disease or negatively influence the animal’s response to vaccination.
Horses that experience prolonged exhaustive exercise or are placed in a new environment are most at risk. It is always a good idea to vaccinate horses when they are rested and prior to entering a rigorous training or showing program. Foals should be vaccinated a few weeks before they are weaned rather than immediately after when they are stressed.
Make sure that your vaccines are handled carefully, your horses are rested and healthy, and that you’ve visited with your local veterinarian about the specific diseases in your area that you should be vaccinating against.