Cold hydrotherapy can reduce some of the inflammation and aid in the cleanup process until a veterinarian can properly debride the wound. Another problem horse owners contend with is a reaction or abscess related to a vaccination. A local or whole body reaction to a number of the equine immunization products is a well-known side effect. These problems, in reality, usually are muscle tissue reaction at the vaccination site. Look for heat, pain, and swelling at the site within two or three days of vaccination.
Some horses demonstrate signs of systemic illness, such as depression, inappetence, and fever.
This type of injection reaction might need to be lanced and allowed to drain, but initially heat should be used at the site. As with cold therapy, it can be overdone. One of my favorite ways to apply heat is placing a wad of cotton in a closable plastic bag, adding water that is just hot enough to hold in your hand. Electric heating pads should not be used as they can burn the skin if not monitored carefully. Severe Dehydration Dehydration can be a significant problem for the performance horse as well as for horses suffering from other disease processes.