It's springtime and time to get ready for upcoming summer and riding. The following are some recommendations for horse vaccinations. I suggest May 1st as a day to vaccinate. It's easy to remember, it gives the horse time to build immunity, also time for a second vaccination if needed and is before flying insects are prevalent.
The most basic horse vaccine to give is tetanus or lockjaw. The disease is caused by a toxin secreted by bacteria that live in the ground and the horse's intestinal tract. Horses are extremely susceptible to it and it is usually fatal. It is a yearly vaccine.
Encephalomyelitis or sleeping sickness is caused by viruses-eastern, western and Venezuelan. It is transmitted by insects from bird and rodent reservoirs. Affected horses die about 90% of the time. It too is a yearly vaccine and recommended.
Influenza is common and highly contagious. As in people, it is hard to develop a highly effective vaccine. New vaccines are being developed. Vaccination is recommended for horses who are around new horses a lot-for example at shows, races, training or breeding barns.
The above three diseases are commonly combined into one vaccine usually referred to as a "4 way" or "5 way" vaccine. The immunity against influenza is usually short lived -3-4 months-so it might be good to booster the horse just for influenza after a 4 way. A 4 way is given once yearly.
Rhinopneumonitis (rhino) is caused by a herpes virus. In all horses- especially young horses- it can cause respiratory disease. It also can cause abortion in pregnant mares. Vaccination is recommended for horses mingling with new horses and pregnant mares at 5, 7 and 9 months of pregnancy.
Strangles is highly contagious. It is transmitted by contact with infected horses or horses that carry it but show no signs. It also can be transmitted by contact with brushes or halters contaminated with nasal secretions or pus. A safe, effective vaccine has been hard to develop. Many types have come and gone over the years. It seems to best be given to horses on premises where strangles is a persistent problem or horses entering a high risk facility. Some boarding stables may require it.
West Nile virus is transmitted by mosquitoes from birds and is a relatively "new" virus to be concerned about. It first appeared on the east coast but has traveled across the country. It is recommended to vaccinate for it yearly.
There are other diseases that are less frequently seen such as rabies and Potomac horse fever. You might discuss vaccinating your horse for these with your veterinarian depending on the circumstances.
If your horse has never had a vaccination or you are unsure of its vaccinations status, it is recommended to give the first vaccine followed by a booster shot in 4-6 weeks. Then annual vaccination (remember May 1st) is recommended.
At times horses will have localized swelling and pain at the site of injection. This usually goes away in a few days but to minimize the consequences I recommend using the chest or back of the thigh muscles-not the neck muscle. You can also hot pack the sore area with a warm washcloth to lessen swelling and pain. If your horse shows other signs such as reluctance to move, eat or signs of colic-please contact your veterinarian immediately. •
[posted April 2006]