A proper vaccination program structured around your horse herd, their movement, time of year and geographic location is only one part of a complete farm management plan, but it is a crucial one. In these harsh economic times, people start skimping here and there and many may not be vaccinating their horses as they have in years past—which can have an effect on everyone’s horses. While it may save them a few dollars short term, an illness to a horse that can come into contact with the horses in your care, will end up costing you and your clients.
Dr. W. David Wilson from the University of California Davis School of Veterinary Medicine lists the following as factors to consider when evaluating risk of exposure to various diseases: age, type, gender, number, use and stocking density of horses; season of the year; environmental conditions; and the farm’s facilities, management practices and geographic location.
Once you have worked out what vaccines your program requires, you can also potentially save costs by giving some of the intramuscular (IM) injections yourself. This is another area to first discuss with your veterinarian because there is always risk involved in giving a horse a shot, and your vet is well trained to handle emergency situations when they arise. He or she can show you the proper way to give an IM injection and together you can determine if you are comfortable doing it. From a liability standpoint, a do-it-yourself approach to vaccinations should only be done on your own horses, and not on your clients’ horses.
The Bare Minimum
First and foremost, it is important to remember that no vaccine can guarantee 100% protection, but most vaccines are highly effective. If possible, shots should be given at the same time to all horses in the herd. This allows for more efficient management, easier record keeping and lower farm call expenses.
The American Association of Equine Practitioners (AAEP) divides vaccinations into two categories: core vaccinations and risk-based vaccinations. Core vaccinations “protect against diseases that are endemic to a region, those with potential public health significance, required by law, virulent/highly infectious, and/or those posing a risk of severe disease. Core vaccines have clearly demonstrated efficacy and safety and thus exhibit a high enough level of patient benefit and low enough level of risk to justify their use in all equids.”
The AAEP lists the following as core vaccines and should be considered the bare minimum for all horse operations: Eastern/Western Equine Encephalomyelitis (EEE/WEE), rabies, tetanus, and West Nile Virus (WNV). The timing of vaccines that protect against vector borne diseases can vary by region. In the southeastern U.S. the need will be much sooner than those horses living in cold or dry climates that don’t see mosquitoes emerge until later in the spring. It may also be necessary to give a second booster in mid- to late summer before the disease peaks. In the case of tetanus vaccine, annually is fine, but Dr. Wilson suggests that a horse facing surgery or that receives a puncture wound should be given a booster if the previous dose of toxoid was given more than six months prior.
For horses living in the Western United States, Dr. Wilson recommends the same core vaccines with the exception of rabies. However, he does say that it should be added to the core list when significant risk of exposure to wildlife vectors of rabies exists.
Venezuelan Equine Encephalomyelitis (VEE) vaccine may only be needed when there is a threat of exposure or as required for interstate or international travel. It is typically available in combination with EEE and WEE.
In knowing your specific situation, additional vaccines to those listed above may be necessary. These are the risk-based vaccinations and may vary between individuals, populations and geographic regions. The AAEP recommends that a risk assess “should be performed by, or in consultation with, a licensed veterinarian to identify which vaccines are appropriate for a given horse or population of horses.” The additional vaccines listed below are not necessary for all programs. “Vaccine scheduling is provided for use after it has been determined which, if any, risk-based vaccines are indicated.”
The AAEP lists the following as risk-based vaccinations: anthrax, botulism, equine herpesvirus (EHV), equine viral arteritis (EVA) for colts and breeding stallions, equine influenza, Potomac Horse Fever (PHF), rotavirus, and strangles. The anthrax vaccine should not be given to a horse currently on antibiotics and extreme caution needs to be taken during storage, handling and administration. Your vet may suggest bi-annual vaccination for EHV in horses that are under five years of age, horses on breeding farms or in contact with pregnant mares and performance horses at high risk. Similarly with PHF, a revaccination interval of three to four months may be considered in endemic areas when the disease risk is high. The rotavirus vaccine is only needed on endemic breeding farms or when the risk of infection is high. Finally, it is important to note that in the case of strangles, vaccination is not recommended as a strategy to control an existing outbreak.
As you can see, there are a variety of diseases that can be managed by vaccinations, but not every horse needs to be vaccinated for every condition. Work with your veterinarian to develop a program for your barn and review it annually or as your needs change.