Your Foal’s Health Vaccination and Worming of Your Foal

The management of your foal’s health begins while the mare is still pregnant. Hopefully she will have received a tetanus vaccination booster around 4-6 weeks before foaling. The newborn foal will have received essential antibodies in the mare’s colostrum during the first suckling but the benefit of these decreases over time. It is vital therefore that you embark on the correct vaccination and worming programs and with the correct timing in order to keep the foal healthy and safe from illness.

Work with your Vet

It is important that you work closely with your vet when it comes to the type and timing of the vaccination program. The general consensus is that vaccination programs begin at around 5-6 months of age however there can be variables depending on your area, i.e. whether there are any special health issues to be aware of, and on whether there has been poor intake of colostrum. Your vet will be able to advise you on any special measures that apply.

Do I Really Need to Vaccinate?

You may think that if your mare and foal are never going to come into contact with other horses or animals, vaccination may not be necessary. Even if this is the case there are still instances where your foal can become infected. The most common dangers for young foals – and indeed for elderly horses – come from tetanus and equine influenza.

Tetanus in particular is a nasty and sometimes fatal disease and the bacteria that cause this live in the soil. It can also live in the horse’s gut and can be passed out in the faeces. This bacteria (Clostridium Tetani) can enter the body through wounds – no matter how small – or through the umbilical stump and if this happens they can wreak havoc, multiplying rapidly to produce the toxins which cause damage to the nervous system. Tetanus incubates for 7-21 days and signs of infection include:

  • Stiffness in the head and limbs
  • Flaring of the nostrils
  • Progressively worsening muscle spasms which may prevent eating

Good hygiene and yard/paddock management, plus careful observation and prompt treatment of wounds, will help to work alongside vaccination to ensure tetanus doesn’t take hold in your foal.

Equine influenza is fairly endemic in the UK horse population and, just as with humans, once it starts to spread it rapidly infects other animals if they haven’t been vaccinated. The simplest and most effective way to prevent a devastating spread of the deadly influenza virus and protect your stock is to make sure you vaccinate against it. When you vaccinate enough horses within a group it creates a phenomenon called ‘herd immunity’. What this means is simply that there is safety in numbers – if there are not enough unprotected animals for the virus to attack then the spread is halted. Strong herd immunity is the best way to protect the health of your horses, especially vital for foals and brood mares.

There have been very recent outbreaks of equine flu in several areas of the country. Unvaccinated horses will present with symptoms such as:

  • Nasal discharge
  • Raised body temperature
  • Fever and reduced appetite.
  • Lethargy

It can also lead to secondary infections or even permanent lung damage. To ensure your foal doesn’t fall prey to this nasty infectious disease work with your vet to develop a customised vaccination program that is suitable for your animals and your area. A series of vaccinations over the first 12 months followed by annual boosters is all it takes to keep your foal safe. And consider that it is easier, safer and cheaper to do this rather than try to treat your foal after it becomes ill.


Young animals are very susceptible to worm infestations and worms can be passed from mare to foal. For this reason it is essential that you monitor the mare in pregnancy and administer appropriate and regular wormers that are safe for pregnant mares. Never neglect the worming process as a worm infestation can be at best debilitating and at worst fatal for a young foal. The one to watch out for is the parasite known as Parascaris equorum, or roundworm. These things can grow up to 40cm long and can block the gut resulting in colic which can sometimes be fatal.  The first signs of infestation can include:

  • Poor growth but with a pot belly
  • Coughing
  • Rough coat and poor condition

The Parascaris worm can be ingested from infected pasture repeatedly and with a life cycle of 10-15 weeks in foals plus the potential for worm larvae to migrate through the lungs and liver it’s clear how dangerous this can be and how important it is to worm correctly. The eggs can lay dormant in pasture for a long time so fresh grazing plays a vital part in preventing reinfestation. The recommended time for dosing against this parasite is around 10-12 weeks of age and again at weaning until the foal has developed a natural immunity.

Other parasites to watch out for include the intestinal threadworm (Strongyloides westeri) which can cause diarrhoea and the Small redworm (Cyathostomins). The first can be passed via the mare’s milk but a worming treatment given to the mare around the time of foaling can help to prevent an infestation. The Small redworm is particularly dangerous for young foals and the consequence of an infestation can be severe or even fatal when the larvae burrow into the large intestine.

As always, take advice from your vet on what is the appropriate worming treatment for your foal and never be tempted to give a wormer that is meant for an adult horse to your youngster. Remember also to treat every part of your property and keep stables and grazing areas scrupulously clean as far as possible. Work with your vet while the mare is in foal to put together a plan for the appropriate and correct worming, vaccination and nutrition needs of your foal and its mother. Do this and you are sure to raise a strong, healthy foal.

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