Food Trial Instructions for Dogs and Cats

The exact mechanisms of food allergy and intolerance are not fully understood in companion animals and contrary to people, these reactions can be delayed in time, taking days to a few weeks to develop (delayed-type hypersensitivity). Therefore, the term «adverse food reaction» is preferred in veterinary medicine. Cutaneous manifestations (itching, otitis, and skin infections) may accompany digestive signs (vomiting, diarrhea, flatulence, increased fecal frequency) and are rarely outgrown.

Potential Allergens

Only a small variety of foods (mainly animal proteins and a few grains) are clearly implicated in dogs and cats according to the current veterinary medical literature. Adverse reactions to chicken, beef, dairy products (cow milk, cheese and yogurt) and wheat account for over 75% of all the reported cases in dogs with adverse reactions to chicken egg, soy, lamb, fish and corn reported much less frequently, while reactions to rice and duck are rare. In cats, adverse reactions to chicken, chicken egg, beef, dairy products, and fish account for over 90% of all the reported cases. There is no scientific evidence of naturally occurring peanut and tree nuts allergy in dogs or cats. Therefore, giving these foods to them is probably acceptable.

Food Trial Defined

Recognizing the exact cause of adverse food reactions in dogs and cats can be difficult. The only way to diagnose an adverse food reaction is to strictly feed a new diet for several weeks. This process is called a food trial (also known as elimination diet trial).

Hypoallergenic Diets

Three types of diets may be used. The first type is a veterinary «novel» diet, which means that your pet has not eaten this protein source in the past (or at least very infrequently). Therefore, an accurate dietary history is essential for a successful outcome. Examples of protein sources include venison, rabbit, pork, kangaroo or fish while recommended carbohydrate sources include sweet potato, white potato or green pea. The second type of diet, a veterinary «hydrolyzed» diet, contains a protein that has been broken down by enzymes to be so small that it should not, in theory, stimulate the immune system. Examples of hydrolyzed proteins include chicken, feather protein or soy. The third type of diet is a complete and balanced «homemade» diet. Please inquire if you wish to feed such diet. We can provide detailed recipes and vitamin/mineral supplements. We can also consult with a veterinary nutritionist if your pet has concurrent disease(s). Please only use the diet that was prescribed. Even though many commercial diets sold over-the-counter may claim to be «hypoallergenic» or «for sensitive skin», it is important to realize these claims have no official meaning. They can be misleading because the pet food companies do not legally have to list every ingredient on the label.

Food Trial

We recommend that you start a food trial using a commercial diet. In order to determine if your pet has a food allergy, this diet must be strictly maintained for a minimum of 2 weeks. You may not see complete resolution of clinical signs but you should see some improvement. This improvement may be slow. Patience and determination are essential for success. It is very important that you adhere strictly to the following guidelines:

1. In order to avoid a digestive upset, please make the diet change from the current diet to the new diet gradually over a week, according to the chart and diagram below.

2. We emphasize that nothing else is to pass the pet’s lips during the trial. For greater clarity: this means no flavored vitamin supplements, chew toys, commercial treats (bones, pig ears, rawhide chews, biscuits), snacks and table scraps. You may use the new diet as a treats. For example, you can use some kibble as a treat if you use a dry formulation. If a canned diet is fed, you can either make meatballs by rolling the food in your hands or bake slices into dry cookies. In doubt, please ask us about other acceptable treats that can be used during the duration of the food trial (slices of dried sweet potato treats, carrots, broccoli, apples etc.).

3. Do not use bread, cheese, Pill Pockets, sausages or meat to disguise oral medications. You can use the canned diet (if available) to make hand-rolled meatballs. You can also use boiled cubes of sweet potatoes to mask the medication.

4. All family members and visitors should comply with the food trial.

5. Eating another pet’s food or feces will disrupt the food trial. Try to monitor the pets or separate the pets when they are fed. Stools will need to be picked up and bagged immediately. Put cat food out of the dog’s reach or feed cats in a separate room. Avoid or stop free feeding all pets in the household in order to control food access.

6. Cats should ideally be kept indoors to prevent hunting.

7. If your pet receives a flavored medication (chewable heartworm/ flea pills; flavored antibiotics; flavored vitamin, mineral, joint or coat supplement), please have those changed to non-flavored form or a topical applied to the skin between the shoulder blades (Advantage Multi, Advantage, Revolution).

8. Make sure you have enough food for a minimum of 6 weeks. It is important not to have breaks during the food trial in order to facilitate the interpretation of results.

9. Please contact us and ask us for instructions if: - The change of diet causes vomiting or diarrhea. - Your pet refuses to eat the new diet. - Your pet goes more than 3 days without a bowel movement. - Your pet appears to lose weight.

Potential Next Steps

A small percentage of truly food allergic pets may remain undiagnosed if a commercially prepared diet is used, as they may in fact be allergic to food additives (food dyes, emulsifiers, stabilizers, flavorings, taste enhancers, and preservatives). These patients may require a second food trial with a homemade diet.

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