Emily Smith answers:
To start with, it’s helpful to know the difference between a feed intolerance and an allergy. An allergy’s an immune system response.
The horse’s body produces antibodies to a specific substance, which sets the stage for an allergic reaction should it come into contact. The signs include hives with raised skin in lumps or patches, hair loss from scratching and itchy, red and swollen skin. On the other hand, a food intolerance is a non-immune system response and your horse has an adverse reaction to a feed. Signs of food intolerance include digestive disturbance, such as loose droppings, scurfy skin and changes in behaviour.