Horses
I spend a significant amount of time working with horse owners and veterinarians on specific nutrition questions they may have. One of the most common questions I get goes something like this:
“I just had a blood test done on my horse, and it came back that he is allergic to corn, oats, and barley. What feed does Purina make that doesn’t contain any of these ingredients?”
I don’t like getting this question, because I know the owner (or vet) will most likely not like my answer. Here’s why…
Food allergies are rare in horses and difficult to diagnose.
There are very few documented cases in the scientific literature of a true food allergy in the horse. It is believed that the overall incidence in the horse population is very low. Many symptoms that are mistakenly attributed to a food allergy in reality are environmental in origin. Allergies to pollens, molds, insects, and ingredients in topical preparations are much more common. Food allergy symptoms are usually not affected by season, and they are not affected by changes in the environment (i.e. bedding, housing location, etc.) If a horse starts to display signs of an allergic reaction (hives, runny eyes, puffy legs, itchy tail, etc.) and there has been no recent change in the diet, then it is most likely an environmental or contact allergy that you are dealing with.
Serum allergy testing is not an accurate way to diagnose a food allergy in horses.
In fact, there are several published veterinary reports that specifically recommend against using serum allergy testing as a diagnostic tool for food allergies due the high false positive rate. Unfortunately, many veterinarians in the field are still using these tests as a “quick and dirty” way to determine if a horse is allergic to something he may be eating. Yes, it is quick, but it is also dirty because the information it provides is basically irrelevant. I cannot blame the vets for doing these tests; they can be useful to identify environmental allergens. I just wish the labs that perform these tests would take out the section on “food-born” allergens; this would eliminate a lot of confusion for both owners and veterinarians.
The only reliable way to diagnose a food allergy is with an elimination diet.
Unfortunately, performing an elimination diet it is not very convenient or easy to do. But for a horse that is suspected to be allergic to something in the diet, going through the steps of an elimination diet is the only way to give them the relief they need without compromising their health and potential usefulness as a performance horse (i.e. putting them on a hay-only diet that is imbalanced, deficient in nutrients, and can't support the demands of exercise).
How to perform an elimination diet:
1) Put the horse on a hay-only diet until allergy symptoms disappear (this may take up to 8 weeks). Ideally, a hay variety that he has never been exposed to should be fed. If symptoms do not disappear, try another variety of hay. If symptoms still do not disappear, it is probably not a food allergy that you are dealing with. Do NOT feed anything else during this time, including grain concentrates or supplements.
2) Introduce one new feed ingredient per week and monitor for the reappearance of allergy symptoms. It is best to start with whole grains/individual ingredients rather than a commercial concentrate, which may contain many different ingredients. If you suspect a beet pulp allergy, then you would want to start with plain beet pulp. Other ingredients to try would be plain oats, corn, barley, soybean meal, etc., depending on what you suspect could be the cause of the food allergy. You may eventually introduce a commercial feed to determine if that particular feed works for the horse or not.
3) If the horse starts to exhibit symptoms when a new ingredient has been introduced, discontinue feeding immediately. Now here’s the important part: once the symptoms have subsided, reintroduce that same ingredient again. This is the “challenge” that is necessary to confirm that this ingredient indeed is the source of the food allergy. If the horse starts to shows symptoms upon reintroduction, then you can confirm that the horse indeed is allergic, or at the very least has an “adverse reaction”, to this ingredient, and it should be avoided in the future.
The “take-home” message here is that food allergies can and do occur in the horse, but they are rare. And while a seemingly convenient way to test for food allergies, serum allergy testing will not give you accurate results. Performing an elimination diet is the only way to confirm whether or not your horse is allergic to something he is eating.
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Horses
The Truth About Food Allergies in the Horse
I spend a significant amount of time working with horse owners and veterinarians on specific nutrition questions they may have. One of the most common questions I get goes something like this:
“I just had a blood test done on my horse, and it came back that he is allergic to corn, oats, and barley. What feed does Purina make that doesn’t contain any of these ingredients?”
I don’t like getting this question, because I know the owner (or vet) will most likely not like my answer. Here’s why…
Food allergies are rare in horses and difficult to diagnose.
There are very few documented cases in the scientific literature of a true food allergy in the horse. It is believed that the overall incidence in the horse population is very low. Many symptoms that are mistakenly attributed to a food allergy in reality are environmental in origin. Allergies to pollens, molds, insects, and ingredients in topical preparations are much more common. Food allergy symptoms are usually not affected by season, and they are not affected by changes in the environment (i.e. bedding, housing location, etc.) If a horse starts to display signs of an allergic reaction (hives, runny eyes, puffy legs, itchy tail, etc.) and there has been no recent change in the diet, then it is most likely an environmental or contact allergy that you are dealing with.
Serum allergy testing is not an accurate way to diagnose a food allergy in horses.
In fact, there are several published veterinary reports that specifically recommend against using serum allergy testing as a diagnostic tool for food allergies due the high false positive rate. Unfortunately, many veterinarians in the field are still using these tests as a “quick and dirty” way to determine if a horse is allergic to something he may be eating. Yes, it is quick, but it is also dirty because the information it provides is basically irrelevant. I cannot blame the vets for doing these tests; they can be useful to identify environmental allergens. I just wish the labs that perform these tests would take out the section on “food-born” allergens; this would eliminate a lot of confusion for both owners and veterinarians.
The only reliable way to diagnose a food allergy is with an elimination diet.
Unfortunately, performing an elimination diet it is not very convenient or easy to do. But for a horse that is suspected to be allergic to something in the diet, going through the steps of an elimination diet is the only way to give them the relief they need without compromising their health and potential usefulness as a performance horse (i.e. putting them on a hay-only diet that is imbalanced, deficient in nutrients, and can't support the demands of exercise).
How to perform an elimination diet:
1) Put the horse on a hay-only diet until allergy symptoms disappear (this may take up to 8 weeks). Ideally, a hay variety that he has never been exposed to should be fed. If symptoms do not disappear, try another variety of hay. If symptoms still do not disappear, it is probably not a food allergy that you are dealing with. Do NOT feed anything else during this time, including grain concentrates or supplements.
2) Introduce one new feed ingredient per week and monitor for the reappearance of allergy symptoms. It is best to start with whole grains/individual ingredients rather than a commercial concentrate, which may contain many different ingredients. If you suspect a beet pulp allergy, then you would want to start with plain beet pulp. Other ingredients to try would be plain oats, corn, barley, soybean meal, etc., depending on what you suspect could be the cause of the food allergy. You may eventually introduce a commercial feed to determine if that particular feed works for the horse or not.
3) If the horse starts to exhibit symptoms when a new ingredient has been introduced, discontinue feeding immediately. Now here’s the important part: once the symptoms have subsided, reintroduce that same ingredient again. This is the “challenge” that is necessary to confirm that this ingredient indeed is the source of the food allergy. If the horse starts to shows symptoms upon reintroduction, then you can confirm that the horse indeed is allergic, or at the very least has an “adverse reaction”, to this ingredient, and it should be avoided in the future.
The “take-home” message here is that food allergies can and do occur in the horse, but they are rare. And while a seemingly convenient way to test for food allergies, serum allergy testing will not give you accurate results. Performing an elimination diet is the only way to confirm whether or not your horse is allergic to something he is eating.
- Formulating Horse Feeds
Different Formulation Strategies Produce Different Results When choosing a horse feed, looking at the guaranteed analysis can help you determine if the nutrition content of that feed is appropriate for the age and activity level of your horse. You would...
- Are Extruded Feeds Easier For A Horse To Digest?
If you have ever fed a commercial dog food product, you know what an extruded feed looks like. Extrusion is simply the process of pushing a mix of heated feed ingredients through small holes under high pressure. You don’t see many extruded horse feeds...
- No Break In R&d For The New Year!
We are trying to get readjusted after the completion of our exercise physiology test in December. After our last data collection day we moved all of the exercise horses out to pasture for a well deserved break. Our broodmares and open mares have all...
- Ration Balancers - What Are They And How Do I Use Them?
You may have heard the term “ration balancer” before, but do you know what it means and how to use it in a feeding program? Even though I’d been around horses most of my life, I had never heard the term until I was in graduate school. Ration balancers...
- Anhidrosis
Unfortunately, it is that time of year again...it is hot, humid, and just plain miserable here in Florida. But what’s even worse than dealing with the intense heat is dealing with a horse that has stopped sweating. Anhidrosis is common problem that...