Foal Vaccines | PetMD

Do foals need vaccinations?

If the mare is vaccinated shortly before giving birth, the newborn foal will be protected from disease by the antibodies in the mare’s milk, but this immunity only lasts for a short time, and foals usually receive a series of vaccinations starting a few months after birth to build up their own immune system.

What is a vaccine?

Vaccines are biological products that protect the body against specific diseases, such as viruses or bacteria, and stimulate the horse’s immune system to recognise, remember and fight off the pathogen when it is naturally exposed to a harmful pathogen.

Vaccines are made from a weakened or inactivated form of a pathogen, such as an inactivated form of the equine influenza virus. When the weakened viral proteins enter the body, the body responds and produces the appropriate antibodies specific to that disease. If the horse is exposed to that bacteria or virus in the future, its immune system can respond more efficiently and effectively.

Vaccines are usually produced as either inactivated or live attenuated vaccines. If both options are available commercially for a particular disease, discuss the pros and cons of each with your veterinarian, as each horse has different needs and one may be more beneficial than the other. Live attenuated vaccines are administered intranasally (through the nose) and may trigger a stronger immune response, which may lead to disease or a vaccine reaction. For immunocompromised or susceptible patients, these may not be ideal. Foals have underdeveloped immune systems, so inactivated vaccines are usually the way to go if both formats are available.

At what age should foals be vaccinated?

Foals begin to develop their own immune system at about 3-4 months of age, but at that point it is still immature and not strong enough to fight off most viruses. To protect them, vaccinations are started to help build up their immunity.

It is important to wait until the mare’s antibodies are no longer active in the foal, as they may counteract the vaccine and cause a negative reaction. Rushing the vaccination can lead to anaphylaxis, shock, increased breathing rate and body temperature, and insufficient protection of the foal. For example, rabies vaccine is given twice to foals from vaccinated mares, but once to foals from unvaccinated mares, as the mare’s antibodies often interfere with rabies for a long period of time. A booster vaccination helps to ensure full protection.

What vaccinations does my foal need?

Core vaccines recommended for all horses include:

Other vaccines recommended by your veterinarian may vary depending on your geographic location and your horse’s lifestyle. Recommended vaccines include:

Foal vaccination schedule

The following describes the core vaccines, the recommended vaccination schedule for foals of vaccinated mares, and foals of previously unvaccinated mares. All core vaccines should be administered annually.

Vaccination every two years (every six months) may vary depending on where you live, the risk factors, and the lifestyle your foal experiences. A multiple dose series is usually required to begin the vaccination process for these diseases, targeting the same foals born to both vaccinated and unvaccinated mares.

Other common Risk-Based Vaccines Schedules vary widely and should be discussed with your veterinarian.

Strangles

Both inactivated and live attenuated vaccines are available for strangles. Vaccination is not recommended during an outbreak as it does not provide full protection and horses may become more susceptible to the disease. After the initial series, vaccinations can be given every 6-12 months.

• The inactivated vaccine is given in three doses: the first at 4 to 6 months of age and then every 4 to 6 weeks.

• The live attenuated vaccine is given starting at 6 to 9 months of age, with a second dose given 3 to 4 weeks later and a final dose given at 11 to 12 months of age.

Leptospirosis

Leptospirosis is a bacterial pathogen and a common cause of recurrent uveitis. Depending on where you live, this vaccine may be recommended. After two doses, the vaccine is given annually.

• The first dose is given at 6 months of age, with a booster dose given 3 to 4 weeks later.

Potomac Horse Fever

Potomac horse fever is a bacterial disease that causes acute and potentially fatal colitis. It is found geographically everywhere, but is most common in the eastern states, where vaccination may be the mainstay of prevention.

• The first dose is usually given at 5 months of age, with a booster dose given 3 to 4 weeks later.

Botulism

Botulism is a Clostridium disease that causes flaccid paralysis and is often fatal. Depending on risk factors, this three-dose vaccine series can be started as early as 2 weeks of age and then every 4 weeks thereafter.

Equine viral arteritis

Equine viral arteritis is a subclinical virus carried by stallions that can significantly increase abortion rates in mares. Young foals that are to be used for breeding purposes should be vaccinated once between 6 and 12 months of age. It is important to have a blood test prior to this vaccination to ensure that the mare does not have any residual antibodies against EVA.

Snake bite

Depending on where you live and your horse’s age, a snakebite vaccine may be recommended. This vaccine is only partially protective against certain types of snakes and is given every 6-12 months after the first dose (3 doses, spaced one month apart).

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