Getting a Good Start

When foals are born, Mother Nature has provided them with good defenses. But they don't last forever. Here's how to vaccinate and worm the young ones.

Your mare successfully delivered a beautiful foal, and that feisty baby has quickly started to grow. Young foals, however, are very susceptible to disease and parasites, so it’s vitally important to provide necessary protection.


Four to six weeks before foaling, the expectant mare should receive boosters using only the killed version of a vaccine. Typically, they are immunized for tetanus, encephalitis, influenza, rhino and Streptococcus equi. Additionally, Potomac Horse Fever and botulism may be given in areas of high risk. With the mare properly protected, a newborn foal will receive antibodies from the mare’s colostrum to help protect him from these diseases.

It is important to test the foal for proper antibody levels within his first or second day. In the past, researchers believed that these antibodies were gone by the time the foal was three to four months of age, so initial vaccines were given when the foal was two- to three-months-old. However, more recent studies have shown the presence of antibodies in foals up to nine months. If the foal still has antibodies from the mare, he won’t produce antibodies from a vaccination. In addition, there is a belief that vaccinating foals too early and often may keep them from reaching their full potential to resist disease as an adult. Studies are ongoing to determine the best time to vaccinate foals.

Typically, foals receive their first shot and then a booster four weeks later. Discuss your specific situation with your veterinarian. Recent research indicates the best time to vaccinate for influenza is no earlier than nine months of age using a modified live vaccine; 10 to 12 months if using the killed version. Type 2 strains with a date from the 1990s or possibly the late 1980s are best so that the foal is protected from the current strains. The initial series of encephalitis shots should be started when the foal is seven- to nine-months-old, and tetanus, rabies and botulism should be given after nine months. Before giving a tetanus vaccine, it is important to examine the foal for deep cuts or puncture wounds. If there are any, give a dose of tetanus antitoxin and wait three weeks before giving the vaccine.


Parasites can do irreparable damage to a horse if not dealt with early and regularly. They are dangerous to the foal’s overall health, growth and resistance to disease. Signs of parasite infestation include unthriftiness, rough hair coat, potbelly, ribby appearance, depression, watery eyes, runny nose and cough. As with vaccinations, it is important to discuss your particular situation with your veterinarian.

Foals should receive their first dose of de-wormer when they are six- to eight-weeks-old and then at one- to two-month intervals thereafter. Once the foal is a yearling, he can join the adult de-worming program. The most important parasites to remove are ascarids (round worms), which are the worst enemy of a foal’s pulmonary and gastrointestinal system, and strongyles (bloodworms), which are devastating to a foal’s intestines, liver and circulatory system.

Nasogastric tubing by your veterinarian will get the quickest, most complete result, but most paste wormers have been approved for use in foals. Ivermectin (Zimecterin®, Rotectin®1, and Equimectrin®) is a broad-spectrum de-wormer that is safe and has not shown parasite resistance. There are other classes of de-wormers that are also safe for foals. The pyrimidines are pyrantel pamoate (Strongid®, Rotectin®2) and pyrantel tartrate (Continuex®, Strongid®C, Strongid®C 2X, Manna Pro®, Purina® and Kaeco). The benzimidazole classes are oxibendazole (Anthelcide®EQ3), oxifendazole (Equi-Cide®, Benzelmin®) and fenbendazole (Safe-Guard®, Panacur®).

Moxidectin (Quest®) is the newest product on the market and is to be used in foals over four months of age. A safety study on Quest® was done by Sarah Ralston, VMD, PhD from Rutgers University. There were three groups of 10 standardbreds: a control, a single double dose and a single triple dose. They were observed for any physical and/or neurological problems, but none occurred. It was concluded that three times the normal dosage could be administered safely.

To ensure the best possible start for your foal, it’s important to stay on top of the latest research in the field of disease and parasite control. By working with your vet and choosing a program suitable for your region and for the foal’s surroundings, they can go on to lead healthy and productive lives.






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