In general, an allergic reaction corresponds to an immunological hypersensitivity with clinical signs, initiated after exposure to a stimulus that does not cause any clinical change in a healthy horse.
In the case of a food allergy, the immune response develops following the ingestion of one or more antigens (molecules recognized as 'invasive' by the equine immune system), called allergens. Among the foods described as potentially allergens are lucerne, barley, beet pulp, wheat, etc.
?Food allergies in horses are rare and difficult to diagnose, and can occur at any age.?
signs of food allergy
Food allergies in horses usually show dermatological signs, such as non-itchy hives, itching and/or scratching lesions. However, they can also manifest themselves through gastrointestinal signs.
In view of the dermatological symptoms presented, other causes of dermatological disease (dermatoses caused by mites, dermatophytosis, bacterial folliculitis, etc.) and other allergic diseases (allergy to insect bites, contact dermatitis or atopy) must be excluded.
Diagnosis
We currently have available:
- intradermal tests, verifying the skin reaction to the inoculation of a possible allergen;
- and blood tests, verifying the reaction of a specific antibody (IgE) to different food molecules in the laboratory.
Intradermal testing has low reliability and blood testing is also not considered a good option on its own, because:
- The allergen causing the allergy may not be included in the allergen panel (and therefore may not be identified);
- Cross-reactions can occur, which can generate false positives.
A group of researchers (Dupond et al., 2016) have even concluded that blood tests, based on the IgE reaction, are unreliable for diagnosing food allergies in healthy horses.
Thus, the most correct method of diagnosis involves an elimination diet, removing food from the horse's diet (ideally for a period of 8 to 12 weeks) and looking for evidence of improvement from a clinical point of view. In general, in allergic horses there is an improvement in 4 to 6 weeks. These horses can then be submitted to a challenge diet in order to confirm the allergen (controlled reintroduction of the suspected food).
Therapy
Currently, therapy involves correct identification of the food allergen and not ingesting it.
In these horses, careful observation and choice of forage feeds and complementary compound feeds (feed and supplements) are recommended. Therapeutic success will depend on the commitment of the owner/rider/keeper to avoid the identified allergens.
INTACOL FOODS
to retain:
- Although no concrete figures are available, food allergies are thought to be rare in horses.
- The food allergy diagnosis process must go through an elimination diet.
- Therapeutic success involves avoiding the ingestion of identified allergens.
