Foals, just as infants, are vulnerable to disease and infection because their young bodies are naive to the world of germs and bacteria. The inclination, particularly for horse owners who choose to vaccinate their own horses, is to administer vaccines as early as possible or as recommended by over-the-counter products. New research, however, seems to indicate that doing so might be a moot point in the very young.

Currently, the majority of vaccines offers only limited protection for the highly susceptible equine neonate. Attention should be given to decreasing exposure to pathogens–those organisms that can cause disease–through isolation and sanitation, as well as by eliminating stressors that reduce the foal’s resistance.

Factors that affect a foal’s immunization program include the management situation, geographic location, and risk versus cost benefits for the owner. Although it is impossible to make universal recommendations for the vaccination of foals, a rational plan can be developed if an owner understands the key decision points in passive and active immunization regimens