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Monitor the vaccination site and keep good records as to which vaccines were given at each particular site in case the horse has a reaction to one of them.
administered via the nostril, is usually given later in the 6 to 8 month range. Again, the risk of contracting the disease must be considered when making these decisions.
If the dam has questionable vaccine history, such as if you purchased her late in pregnancy
or with her new foal at side and don’t have her vaccination records, you might start the foal’s vaccinations a little early. “If the foal is doing well, however, and it’s a low-risk environment and he nursed on time, you might wait the usual length of time. But this might be up to the veterinarian to make this decision. It’s not the same for every foal and every situation,” she explains. It’s always wise to work closely with your veterinarian to figure out some of these variables.
Dr. Julie Wilson, of Turner Wilson
Equine Consulting in Stillwater, Minnesota, emphasizes the fact that standard recommendations sometimes should be modified based on risk. “It’s not one size
fits all. These are just guidelines, and each
farm or horse owner needs to work with their veterinarian to fine-tune a vaccination program/ schedule to fit each situation. Until we have
a way to predict when we can successfully vaccinate each individual foal - since the passive immunity from maternal antibodies, which interfere with vaccination success, will wane at different times, in different foals - in some situations where there is overwhelming risk, you may need to start vaccinating earlier than recommended,” she says.
“This is definitely the case with foals
in Florida, with EEE (Eastern Equine Encephalomyelitis) being such a high risk during mosquito season. We’ve seen young foals from properly vaccinated mares still get the disease. During that vulnerable period before 6 months, it’s better for Florida horse owners to go ahead and start vaccinating foals at 2 to 3 months rather than waiting until 4 to 6 months,” says Wilson.
“Sometimes veterinarians make recommendations that are ignored. With the economy the way it is, many people are trying to minimize use of vaccines or may not understand where or when the risks are. I had a conversation recently with a frustrated California practitioner who has a client who thought that because his horses don’t go anywhere they are not at risk
for West Nile Virus, not understanding that
the disease is transmitted by mosquitoes, not horses,” says Wilson.
“Foals are a very special category because you can’t just say all foals should get a certain vaccination, especially if you don’t plan to appropriately vaccinate the mare ahead of foaling as well. Some horse owners want to minimize the number of vaccines given, and fail to realize that there are strong recommendations for the broodmare in late gestation to reduce the foal’s vulnerability, as well as recommendations for the foal. These are interlinked, rather than independent,” she explains.
Some foal owners also don’t realize that foals will need multiple booster shots during
that first year due to their variable immune response to vaccination, whereas a previously vaccinated adult may only need an annual booster. There is also a growing belief among horse owners that giving too many vaccines
is not healthy. This is a grave misconception, especially if people decide to stop vaccinating their horses for the potentially fatal diseases (tetanus, EEE/WEE, WNV and rabies) that are designated by the AAEP as requiring “core” vaccines for protection.
“We should try to maximize the impact
of our vaccines based on timing, frequency and choice of individual vaccines. At the same time, we have to practice good management to minimize exposure,” says Wilson. No vaccine is perfect, and individual responses to vaccines vary. A few horses don’t mount a strong immune response.
“The appropriate time to start routine vaccinations will vary, depending on the environmental risks on that particular farm. In Florida, I would start vaccinating foals for EEE at 2 months of age, knowing that it may not
be effective yet. In this instance, I would much rather over-vaccinate for that disease because
it has a 90% mortality rate than wait until 6 months of age to vaccinate and run the risk of losing a foal,” she says.
“The immunity from colostrum usually wanes between 2 and 3 months of age. If you add early weaning on top of that, you have a stressed foal with low antibody levels. This
SPEEDHORSE, March 8, 2013 31
EQUINE HEALTH
Dr. Caitlin Rothacker