Diet Trial

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A diet trial is a period of time that your pet will be fed a different diet. This new diet will either be an exclusion diet, where ingredients that a patient has previously encountered will be excluded, or a change to a hydrolysed diet, where the proteins been broken down to a size so small that the immune system no longer reacts to them.




The duration of the diet trial is related to your pet’s condition and the severity of the clinical signs, but for internal medicine purposes typically ranges between two to four weeks.

Why is a diet trial needed?

A diet trial with an exclusion or hydrloysed diet is part of a diagnosis and is also essential in the management of some gastrointestinal diseases. The diagnosis of food sensitivity requires improvement of the clinical signs when the food is changed and the return of the signs after reintroduction of the previous diet. Often when a patient improves on a diet trial, long term use of this diet could be considered.

What are the clinical signs that may prompt the suggestion of a diet trial?

Clinical signs associated with dietary sensitivity/intolerance include a wide variety of clinical signs from gastrointestinal signs, as vomiting or diarrhoea, to dermatological signs, as otitis or itchy skin, and respiratory signs, as sneezing or wheezing.

Can I still give treats to my dog during a diet trial?

Treats or animal-based chews cannot be offered during a diet trial. If a diet trial with a hypoallergenic diet is elected, the dry biscuits of this food can be given as treats.

My pet shares food with my other pets. Can I give the same food to all of them?

In cases like this it is probably best for all animals in the house to be fed the same type of food. Please speak with your veterinarian before changing your other pets diets as sometimes this may not be advisable, particularly if one of your other pets is on a prescription diet.

How much should I feed my pet?

If you have elected to feed your pet a home-cooked diet then the amount to feed will be instructed by the nutritionist who formulated the diet. If a hydrolysed diet or an exclusion commercial diet is fed then manufacturer instructions should be followed but the exact amount can also be discussed with your veterinarian.

What should I give my pet to drink?

Only plain water should be given. Flavoured water or other liquids, e.g. milk, are not allowed.

Should I continue to give my pet is supplements/vitamins or chronic medication?

Some medications and/or supplements may contain animal protein in their formulations and they may need to be stopped or substituted during the diet trial. Speak with the attending veterinarian of your pet to formulate a plan regarding your pet’s supplements/vitamins or medication.