Dr. Mickelson, DVM
Equine Vaccination and Deworming Protocols
Equine Vaccination and Deworming Protocol
If you are unsure of a horse’s vaccination history or if you have a horse that has gone over 18 months without vaccinations, treat that horse as if it has never been vaccinated and follow the recommended booster schedule. Foals should be vaccinated for the first time at 3-4 months old.
Booster Schedule: Vaccines should be administered in the spring (March, April or May) and boostered annually (yearly). Horses receiving vaccinations for the first time should receive another dose of the same vaccine 3-4 weeks after the initial vaccine. Horses traveling to the southern states during the late fall and winter should be boostered in October.
Low Level of Exposure
Horses that do not come into contact with other horses.
Eastern and Western Encephalitis, Tetanus & West Nile ( E, W, T, West Nile)
Eastern and Western Equine Encephalitis & West Nile virus are spread by flying/biting insects. They are viral diseases that affect the nervous system of horses. Unvaccinated horses are at a much higher risk of contracting and dying from the diseases. Eastern Equine Encephalitis and West Nile Virus have both been diagnosed in Washburn and Sawyer county in 2018.
Tetanus: infections originate from puncture/laceration wounds. The bacteria that causes tetanus (a Clostridium) resides in the soil in all climates.
Optional - Rabies - Rabies virus is most commonly spread via a bite from an infected animal. Horses out on pasture or in barns are potentially at risk of exposure. Rabies virus is most commonly found in skunks, raccoons, fox and bats.
High Level of Exposure
Horses coming into contact with other horses (fairs, 4-H, shows)
Eastern and Western Encephalitis, Tetanus & West Nile (E, W, T, West Nile)
Optional - Rabies -
Influenza and Equine Herpesvirus/Rhinopneumonitis (Flu/Rhino)
o Spread via horse to horse contact and contaminated objects (brush, buckets). Influenza commonly causes an mild to moderate upper respiratory infection that inhibits horses performance for 2-3 weeks. However, an Influenza or Flu/Rhino infection can predispose horses to more serious conditions such as pneumonia.
(optional) Streptococcus equi equi aka Strangles
o Spread from horse to horse and/or contaminated objects/environment. Disclaimer: the strangles vaccine may not totally prevent an infection-however, it will reduce the severity and likelihood of severe complications. Very rarely, illness secondary to the administration of the vaccine has been reported. If you're unsure of the strangles vaccination status of your horse or if your horse has been exposed to strangles and may have a 'natural immunity'; then an blood draw to determine a "strangles titer" would be appropriate to determine whether your horse has an appropriate immune system to fight off a potential strangles exposure.
What about the neurologic form of equine herpes (EHV-1)?
Equine Herpes Virus has multiple forms, but the most common are EHV-1 and EHV-4. EHV-1 has been associated with equine abortions. And EHV-1 & 4 cause a respiratory illness known has rhinopneumonitis. Only EHV-1 has been shown to mutate and then cause the deadly neurologic symptoms. Current vaccines protect against the respiratory illness and abortions caused by Equine Herpes Virus. Cross protected against the neurologic form has been speculated, but NOT proven. Therefore, a vaccine does NOT exist that definitely protects against the neurologic form of EHV-1. Exercising good biosecurity protocols while at horse shows and events is the best means of protection.
The American Association of Equine Practitioners (AAEP) has the rabies vaccine listed under the “minimum” requirements for horses. The state of Wisconsin does not require your horse to be vaccinated for rabies.
**Deworming** Protocol based on AAEP standards.
Perform Fecal Egg Count (fecal analysis) on individual horses or pooled samples to get
herd representation in spring (March, April, May). Deworm all horses based off results of
the fecal egg count.
Certain intestinal parasites, tapeworms and bots, cannot be detected on fecal egg counts.
For this reason, at least twice yearly deworming with an ivermectin(moxidectin) &
praziquantel based product is still recommended.
If I still have to deworm twice yearly, why perform a fecal egg count?
Fecal analysis will indicate if additional deworming is necessary. This method of deworming
will help prevent or eliminate drug resistant parasites and ensures proper usage of dewormers.
March or April: Collect & submit feces for fecal egg count
Results of Fecal Egg Count based on eggs per gram (epg)
o 0-200 epg: Deworm with ivermectin (moxidectin) & praziquantel based product,
repeat same product in October, November or December.
o 200-500 epg: Deworm with ivermectin (moxidectin) & praziquantel based product.
Deworm again in 6-8 weeks- Fecal analysis will dictate the appropriate dewormer
needed. Deworm once more in October, November or December with same
product used in spring.
o Over 500 epg: Deworm with ivermectin (moxidectin) & praziquantel based
product. Deworm twice more at 6-8 week intervals. Repeat fecal analysis in Fall.
Depending on the weather- an additional dose of ivermectin may be necessary in December to
remove bots if horses were able to graze on unfrozen pasture after fall deworming.
Type of Dewormer
Resistance to intestinal parasites has also been reported secondary to ineffective
ingredients in some dewormers. For this reason, we recommend using Zimectrin Gold as the
sole deworming product. Zimectrin Gold contains both ivermectin and praziquantel.
During annual spring appointments, if you purchase Zimectrin Gold through Leading
Edge Veterinary Services, we will offer free administration at the time of the farm visit.
For any additional questions or concerns or to set up an appointment for annual vaccinations, wellness exams, coggins or deworming please call the clinic at 715-934