Vaccination Schedule - A Brief Review
Leah C. Gray, DVM, diplomate ACVIM

PRAIRIE EQUINE HOSPITAL, PLLC,
920 West Prairie Ave., Coeur d’Alene, ID 83858
208-762-0930 • Fax: 208-772-3386

PERFORMANCE / SHOW (i.e. IN CONTACT) HORSES

1. Vaccinate once yearly with eastern & western encephalitis (sleeping sickness), tetanus, & rabies.

2. Vaccinate every three to four months with influenza & rhinopneumonitis. (These are the most common upper respiratory viral diseases.)

a) There are basically two ways to approach this regimen. There is a combination vaccine available called Prestige II that combats both influenza & rhinopneumonitis. It is given intramuscular every three to four months, depending on the exposure status of the horse.

b) The other product available is a modified live intranasal influenza vaccine. The manufacturer recommends that this product be given every 6 months. It is an excellent product because it gives local protective immunity in the back of the nasopharynx where the viruses replicate.

c) They are still working on a combination intranasal influenza & rhinopneumonitis vaccine. PEH is anxiously awaiting its arrival.

d) Influenza & rhinopneumonitis are very common & are extremely contagious. There have been several cases around our area this season. The most common clinical signs are coughing, high fever (103-106+F), & serous (clear) nasal discharge. It is spread by aerosol, by fomites, (e.g. brushes or hands), & by direct contact. Most horses do not need to be treated unless a secondary bacterial infection has occurred & there is potential for secondary pneumonia. The incubation period, from exposure to onset of clinical signs for these viruses can spread rapidly. It usually takes approximately 2-3 weeks for recovery. It is important not to put horses back into work too quickly because the respiratory tract needs adequate time to heal.

3. The other vaccine that is routinely given is intranasal strangles. Again, administration of this vaccine depends on the exposure status of the horse. It can be given in an outbreak situation to exposed horses to prevent the spread of respiratory disease. The manufacturer recommends that the product be given initially, then boosted in three weeks, & revaccinate annually.

PREGNANT MARES

1. Pregnant mares should be given a killed form of rhinopneumonitis (called “herpes abortion”). This is given during the 5th, 7th, & 9th month of gestation. 2. They should be given a four-way (tetanus, eastern & western encephalitis/ sleeping sickness, & influenza) & rabies thirty days prior to foaling. This allows for maternal antibodies to accumulate in the colostrum.

FOALS

1. If the above protocol is followed for pregnant mares, then foals should not need their first vaccines until 6-9 months of age. In fact, if vaccines are given too early, then maternal antibodies may actually block the vaccine. Foals should be given a 5-way & rabies, boosted in three weeks, & then revaccinated annually, depending on the exposure status, or following the above protocol for performance horses. 2. Remember that yearlings & two-year-olds are more susceptible to the upper respiratory viral diseases & may need to be boosted more often.

BACK YARD HORSES

A 5-way & rabies once yearly should suffice for horses not in contact, travelling, or competing.

Leah C. Gray, DVM, dip, ACVIM