Page 108 - January 2017

Carolyn Hammer, Director of the Equine Science Program at North Dakota State University, suggests vaccinating foals ahead of weaning stress, which can lower immunity,
so they have a chance to start building their immune system before they are weaned. For recently purchased foals, vaccinate as soon as possible to ensure protection.
It always helps to know the foal’s situation and risk and vaccinate accordingly. “There are vaccines for many different diseases, and some may not be needed, if your foals don’t have exposure and would be unlikely to get those diseases. On a large breeding farm this could save a lot of money if there are some vaccines
you don’t need,” she says. It’s also good to know each mare’s vaccination history, espe- cially if you purchase a broodmare or a mare with a young foal at her side.
“There are many diseases and many differ- ent vaccines, and this is good reason to work with your veterinarian to determine which vaccines should be used and which ones might be best for the mares and foals on your farm,” she explains.
Carrie Hammer, State Horse Extension Specialist and Director of the Equine Science Program at North Dakota State University, has two sets of recommendations for horse- men-those who are raising their own foals and those who are buying weanlings or yearlings. They need to know the vaccination history on those young horses, if possible.
It is important to follow label directions
on every vaccine and give the booster doses
at appropriate intervals. Adult horses that
have already been vaccinated—having gone through the booster series as foals and having received annual boosters thereafter—only need one shot to kick up the immunity. “Almost all vaccines, except rabies, are gener- ally a 3 dose series initially. You start with
the first one at 4 to 6 months of age, then a booster 4 to 6 weeks later and then the foal should get the third dose at about 10 to 12 months of age. After that, they are good for a year or 6 months, depending on which vaccine it is and how frequently it needs to be boost- ered,” she says.
Timing and when to start the vaccines
can sometimes be a hard decision. “We talk about vaccinating about weaning time (4 to
6 months), but doing it at the same time you pull the foals off the mares, when you handle the foals 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 happening,” 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 vaccinated. This is all the more reason to make sure it gets booster shots, since the immune system may have suppressed at the first vac- cination,” 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 accomplished. Having a good plan for weaning and vaccinat- ing is always a good idea.
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 recom- binant, or modified live. It can be confusing, when trying to decide on what to use, with several different brands and combinations. Your veterinarian 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 anti- dote 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 com- bination vaccine containing 4 or more antigens
If possible, vaccinate before 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.
106 SPEEDHORSE, January 2017
equine health