Tel: (585) 889-1170

Vaccination and Deworming Schedules

Deworming Updates!

More Monitoring, Less Medicating


GVEC strives to stay on top of the latest research in veterinary medicine. There has been a dramatic shift in traditional thinking and methods regarding parasites and deworming. Significant resistance to current deworming products has been extensively documented. Much like antibiotic resistance, this stems from years of repeated use of the same products. There are no new, safe, and effective deworming products that are likely to be approved in the near future, so if we as horse owners and veterinarians do not change our current habits, our horses will soon be faced with an army of resistant parasites. In light of these new findings we have changed our recommendations for parasite monitoring and elimination.


While the new program may seem more complex than older methods of worming, please remember that there is always a GVEC veterinarian available to answer any questions you may have.




1) A fecal is a gross and microscopic examination of your horse’s manure. How fecal samples are collected, handled, and stored directly affects the accuracy of the test results.


***The fecal sample should be no more than 12 hours old, and only 5 — 10 grams of feces ( two balls of manure) in volume. A whole pile is not necessary! If a sample is collected and needs to be stored for a short period of time, it can be refrigerated. Never allow the manure to freeze or leave it in the car on a hot summer day. Manure balls can be submitted in any clean container or a resealable plastic bag. Label the sample with the horse’s name, and be sure that the sample was collected from that particular horse. A random sample from the pasture may be too old to be useful, and we can’t target your horse’s individual health needs if the samples aren’t correctly identified.


2) When you bring us your fecal sample let us know if this is a routine check or if the veterinarian requested that you check the horse due to health issues or a previously high parasite load. Also let us know when you last dewormed the horse and what product you used. Don’t bring a sample in within two weeks of the horse’s last deworming. The results will be distorted because the horse is shedding parasite eggs that are being removed by the dewormer.

Our licensed veterinary technicians will examine the fecal sample and identify what types of parasites, if any, are present and the number of eggs per gram of feces. Once the fecal analysis is completed the doctor or technician will contact you by phone or e—mail. If you have any questions please contact the office at 585—889—1170.


3) Moxidectin should not be given to miniature horses, foals less than 6 months old, pregnant mares, or ponies under 500 pounds.



Helpful Hints for Reducing Parasite Contamination

  1. Keep the density of pastured horses to a minimum. This reduces overgrazing and parasite egg contamination.
  2. Pick up and dispose of manure regularly (ideally 2 x a week).
  3. If you want to spread manure, completely compost it first.
  4. It is not a good idea to harrow pastures, as horses create dirty and clean areas in the pasture themselves. If manure is harrowed or broken up, you will contaminate a larger area. If you prefer to harrow, try to do it during a hot spell, and keep the horses off the pasture for 2 weeks.
  5. We are trying to control, NOT eliminate all parasites. We want horses to get a low level of exposure to build some level of resistance.
  6. Use a hay and grain feeder to keep the horses from eating off the ground, where they can potentially ingest more parasites.
  7. Manually remove bot eggs from your horse’s haircoat.


1st Year on program
Adult, low shedder
Deworming productFecal?
April 1Moxidectin / praziquantelYes, pre-deworming
July 15NoneYes
October 1Ivermectin / praziquantelYes, pre-deworming
December 1None Yes



Established on Program
Adult,  low shedder
Deworming product Fecal?
April 1Moxidectin / praziquantelYes, pre-deworming
October 1Ivermectin / praziquantelYes, pre-deworming
December 1None Yes, unless Oct 1 was NPF*


*NPF = No Parasites Found



High Shedder
Deworming productFecal
April 1Double dose fenbendazole x 5 daysYes
May 1Moxidectin / praziquantelYes, pre-deworming
June 1PyrantelYes, pre-deworming
Mid August 1IvermectinYes, pre-deworming
Mid October 1Ivermectin / PraziquantelYes, pre-deworming
December 1OxibendazoleYes, pre-deworming


** Please note: any of the above schedules may be adjusted at the DVM’s discretion depending on the individual horse’s response .

Foals -12 months
Things to remember:


  1. Deworming with ivermectin should control ascarids.  This is a very important parasite in foals up to 8 months.
  2. Tapeworms are rare in foals less than 7 months old.
  3. Foals acquire immunity to strongyloides at 4-5 months, immunity to ascarids at 8 months.
  4. Moxidectin not licensed for use in foals less than 6 month old.
  5. Ideally, a FECRT (fecal egg count reduction test) should be performed on the farm for all foals in order to determine which deworming product is most effective. This requires a fecal exam prior to the first deworming and 2 weeks after the first deworming.


(Note: Mares should be dewormed either 4-6 weeks PRIOR to foaling OR withing 24 hours POST foaling with IVERMECTIN)


Age of FoalProductFecal exam
6-8 WeeksOxibendazole (Anthelcide)Pre –deworming + 2 weeks after
14-16 WeeksPyrantel (Strongid, Exodus)No
22-26 WeeksOxibendazole (Anthecide)No
30-36 WeeksIvermectin (Zimectrin, Equimectrin)Yes
>38 WeeksFollow adult scheduleFollow adult schedule


***One of the major concerns is parasite resistance in foals. The above schedule is strictly for farms / foals that have no resistance problems. The first 2 fecals (before and after the initial deworming) are VERY important to establish dewormer efficacy. If you skip these fecal exams, we have no idea whether the deworming medication is useful in your foal / on your farm.


Strongid C 2x Pelleted Daily Dewormer


Some horse owners choose to give their horses a daily dewormer such as Strongid C, Strongid C2X, or Continuex.
All daily dewormers are small doses of the drug pyrantel. The idea behind daily dewormers is that the continuous presence of this drug will keep strongyle and ascarid loads low. However, daily dewormers do not address bots, are of limited effectiveness against tapeworms, and have the potential to select for drug resisitance.
We advise that horses on daily dewormers continue to be monitored with fecal egg counts 4 times per year and receive an avermectin/praziquantel product in the spring and fall.


Vaccination Recommendations




Foals receive some immunity from their dams at birth as the first milk, also called colostrum, contains antibodies that help protect against infectious disease. Foals should have a blood test run soon after birth to be sure they have received adequate immunity from their mothers. Foals who nurse well and absorb antibodies at birth should wait for their first vaccinations until they are four months of age. The following schedule is advised:

4 Months: Eastern and Western Encephalomyelitis
Tetanus, West Nile Virus, Rabies, Rhinopneumonitis, intramuscular (IM) Flu ** If the foal is in a high risk barn, intranasal flu vaccine can be substituted for the intramuscular flu vaccine, but this vaccine is started at the 7 month visit and boosted at greater than 11 months.

+/- Potomac Horse Fever—This vaccine is given on many area farms; discuss with your veterinarian.

5 Months: Repeat above vaccines. Give first intranasal flu if substituting for intramuscular flu vaccine.

10–12 Months: Repeat all of the above vaccines except Potomac Horse Fever–PHF not need a third booster. Add a booster for intranasal Influenza vaccine if substituting for intramuscular flu vaccine.

Strangles vaccine can be given to foals if exposure is anticipated. It is administered intranasally in a series of two vaccines spaced at least three weeks apart. We recommend that the Strangles vaccination be done at a separate appointment from other vaccines. You should discuss the risk potential for Strangles on your farm with a veterinarian.


Yearlings and Adults


Some of the diseases that horses can contract can occur at any time of the year (Tetanus, Strangles, Rabies). Other diseases are more common in the warm months, either because insects are active or disease exposure increases as horses travel and compete. Most people opt to give the annual vaccines in the spring and boost for certain seasonal diseases one to two more times a year, depending on their horse’s exposure risk. What follows are schedules for several different types of horses.


Stay-at-Home Horses


For horses stabled with one or two others, ridden mostly in summer and fall:

Spring: Eastern and Western Encephalomyelitis, West Nile Virus, Tetanus, Rabies, Rhinopneumonitis, Influenza (intranasal or intramuscular preparations are available), +/- Potomac Horse Fever (discuss with your vet)

Summer and Fall: Owners that choose to vaccinate for strangles may do so in the fall. Horses that associate with outside horses benefit from a booster for rhinopneumonitis and influenza in the fall.


Traveling Horses


Horses stabled at large stables, at racetracks or who travel often to compete:

Spring: Eastern and Western Encephalomyelitis, Tetanus, West Nile Virus, Rabies, Rhinopneumonitis, Influenza (intranasal or intramuscular preparations are available), +/- Potomac Horse Fever (discuss with your vet)

Fall: Rhinopneumonitis, Influenza, Strangles (best to administer this vaccine on a separate appointment)

Winter: Discuss needed vaccines with your veterinarian; schedule depends on whether horse is traveling south

We recommend that ALL HORSES receive WNV vaccine at least once. If a horse has never been vaccinated before, it will need a series of two vaccines spaced three to six weeks apart to get started. Foals will need a series of three vaccines starting at six months of age.


Pregnant Mares


The early months of pregnancy are critical for healthy organ development of the fetus. For this reason, we try to avoid all drug administration of any sort, including vaccines and dewormers, in the first 60 days of pregnancy.

Five, Seven, and Nine Months of Gestation: Pregnant mares are at risk of abortion from rhinopneumonitis, and an approved vaccine for the abortion strain of rhino should be given at five, seven, and nine months of gestation.

We also advise that mares that have never been vaccinated for West Nile Virus be given their first dose of this vaccine at nine months.

Ten Months of Gestation: Vaccinate for Influenza, Eastern and Western Encephalomyelitis, Tetanus, West Nile Virus, Rabies and Potomac Horse Fever (if the farm vaccinates for this disease).




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