Page 28 - Canada Spring 2019

Some horses react negatively to certain vaccines. Instead of giving a combination vaccine with multiple antigens, administer vaccines individually. This way, you can single out any that may cause a reaction and plan boosters accordingly.
When vaccinating foals, make sure the foal is well restrained, use proper techniques, and follow label directions for the product. “There are several types of vaccines that come in dif- ferent forms—such as inactivated, or recombinant, or modified live. It can be confusing, when trying to decide on what to use, with several different brands and combinations. Your vet- erinarian can answer questions about the vaccines and proper vaccination techniques, or tips on vaccinating a foal versus an adult horse,” she says.
“Foals are more likely to have some adverse reactions to modified live vaccines than are adult horses, so it’s good to be prepared and know what to watch for and how to handle those and not get too concerned if it’s just a mild reaction. It’s always good to have an antidote on hand in case of a more severe reaction,” says Hammer.
Some horses react more adversely
to certain antigens, or adjuvants, and if you give a combination vaccine containing 4 or more antigens you wouldn’t know which part caused the reaction. “Sometimes it’s wise to sepa- rate these out and not give everything all at once in a 7-way vaccine. When I work with owners whose horses react, we give the vaccinations separately until we figure out which one is the culprit and plan the subsequent annual boosters accordingly. But with a foal, it will be the first time it’s ever been vac- cinated, and it may be wise to not give everything all at once,” she says.
“The literature tells us, from a research standpoint, that it is better to give the vaccines singly and not all at the same time. But for practi- cal purposes, this isn’t always pos- sible. If you give one, wait a week,
and do something with them, may not be the best time to vaccinate them. There has been research in cattle, swine and other animals showing that the immune system is suppressed by stress, such as during weaning. Recent research at the University of Kentucky, looking at this scenario in horses, shows the same thing is hap- pening,” says Hammer. It’s best
to vaccinate foals ahead of their weaning stress, so they have a chance to start building immunity before they are weaned.
“You don’t always have this opportunity, however. If you have just bought the foal, you generally want to get it vaccinated as soon as possible, to have protection. If a foal has just been weaned (maybe at a breeder’s production sale,
with the pair coming in together and then mare going out one door and the foal another—to the new owner), you want to get it vacci- nated. This is all the more reason to make sure it gets booster shots, since the immune system may have suppressed at the first vacci- nation,” says Hammer.
If it’s your own mare or group of mares, you might be able to vaccinate ahead of weaning or utilize a weaning strategy that is less stressful for the foal—such as mare and foal in adjacent stalls or fence line weaning where they can be next to each other. The foal can’t nurse but still feels secure until weaning is accom- plished. Having a good plan for weaning and vaccinating is always a good idea.
28 SPEEDHORSE CANADA, Spring 2019
EQUINE HEALTH