What is the difference between an allergy and an intolerance in horses?

The terms "allergy" and "intolerance" are often used interchangeably, but they refer to different reactions in horses. An allergy involves the immune system, while an intolerance does not. Allergic reactions do not usually cause symptoms on the first exposure to an antigen. Reactive lymphocytes are generated that only take action when the individual is re-exposed to the antigen.

What is a Horse Allergy?

A horse allergy is an inappropriate immune response to a harmless substance, known as an allergen. The immune system recognizes a foreign molecule but cannot discern between molecules that are characteristic of potentially infective agents and those that are not. Common allergens for horses include:

• Pollen
• Fungal spores
• Animal dander and feathers
• Plant seeds
• Insect bites
• Certain medications

Allergic reactions can manifest in various ways, including skin issues (hives, itching), respiratory problems (coughing, wheezing), or digestive upset.

What is a Horse Intolerance?

An intolerance, on the other hand, does not involve the immune system. It is typically a digestive issue where the horse has difficulty processing a particular food or substance. For example, horses are extremely susceptible to forage poisoning and respiratory complications, and silages of all sorts should be avoided since horses and mules are extremely susceptible to botulism and digestive upsets.

Key Differences Between Allergies and Intolerances

| Feature | Allergy
|