Hill’s Prescription Diet Z/D Canine Dog Food is not rated due to its intentional therapeutic design.
The Hill’s Prescription Diet Z/D Canine product line includes one dry dog food, a recipe designed to help in the treatment of food sensitivities.
Hill's Prescription Diet Z/D Canine Ultra
Dry Dog Food
Estimated Dry Matter Nutrient Content
Ingredients: Starch, hydrolyzed chicken liver, soybean oil, hydrolyzed chicken, powdered cellulose, lactic acid, dicalcium phosphate, calcium carbonate, glyceryl monostearate, potassium chloride, iodized salt, choline chloride, vitamins (vitamin E supplement, l-ascorbyl-2-polyphosphate (source of vitamin C), niacin supplement, thiamine mononitrate, vitamin A supplement, calcium pantothenate, biotin, vitamin B12 supplement, pyridoxine hydrochloride, riboflavin supplement, vitamin D3 supplement, folic acid), dl-methionine, minerals (ferrous sulfate, zinc oxide, copper sulfate, manganous oxide, calcium iodate, sodium selenite), taurine, mixed tocopherols for freshness, natural flavors, beta-carotene
Fiber (estimated dry matter content) = 2.9%
Red items indicate controversial ingredients
|Estimated Nutrient Content|
|Dry Matter Basis||20%||13%||59%|
|Calorie Weighted Basis||18%||29%||53%|
The first ingredient in this dog food is starch. The source of this starch is unknown but it is most likely derived from corn or wheat. Without more information, it’s impossible to adequately judge the quality of this ingredient.
The second ingredient is hydrolyzed chicken liver, organ meat that’s been chemically broken-down into its component amino acids. Hydrolyzed proteins are considered hypoallergenic.
The third ingredient is soybean oil which is red flagged here only due to its rumored (yet unlikely) link to canine food allergies.
However, since soybean oil is high in omega-6 fatty acids and contains no omega-3’s, it’s considered less nutritious than flaxseed oil or a named animal fat.
The fourth ingredient is hydrolyzed chicken, meat that’s been chemically broken-down into its component amino acids. Hydrolyzed proteins are considered hypoallergenic.
The fifth ingredient is powdered cellulose, a non-digestible plant fiber usually made from the by-products of vegetable processing. Except for the usual benefits of fiber, powdered cellulose provides no nutritional value to a dog.
The sixth ingredient is lactic acid, a compound found naturally in many living organisms. It’s likely added here to adjust the pH of the product which (in turn) reduces the growth of unwanted biological contaminants.
The seventh ingredient is dicalcium phosphate, likely used here as a dietary calcium supplement.
The eighth ingredient is calcium carbonate, likely used here as a dietary mineral supplement.
From here, the list goes on to include a number of other items.
But to be realistic, ingredients located this far down the list (other than nutritional supplements) are not likely to affect the overall rating of this product.
With two notable exceptions…
First, we find no mention of probiotics, friendly bacteria applied to the surface of the kibble after processing to help with digestion.
And lastly, the minerals listed here do not appear to be chelated. And that can make them more difficult to absorb. Non-chelated minerals are usually associated with lower quality dog foods.
Hill’s Prescription Diet Z/D Canine Dog Food
The Bottom Line
Although this is a prescription product, our review has nothing to do with the accuracy of claims made by the manufacturer as to the product’s ability to treat or cure a specific health condition.
So, to find out whether or not this dog food is appropriate for your particular pet, you must consult your veterinarian.
With that understanding…
Judging by its ingredients alone, Hill’s Prescription Diet Z/D Canine Ultra looks like an average dry product.
But ingredient quality by itself cannot tell the whole story. We still prefer to estimate the product’s meat content before concluding our report.
And a fat-to-protein ratio of about 68%.
Below-average protein. Below-average fat. And above-average carbs when compared to a typical dry dog food.
Free of any plant-based protein boosters, this looks like the profile of a kibble containing a limited amount of meat.
Hill’s Prescription Diet Z/D Canine Ultra is a plant-based kibble using a limited amount of hydrolyzed chicken liver as its main source of animal protein.
Hill’s Prescription Diet Dog Food
The following list (if present) includes all dog food recalls since 2009 directly related to this product line. If there are no recalls listed in this section, we have not yet reported any events.
- Hill’s Science Diet Dog Food Market Withdrawal of November 2015 (11/29/2015)
- Hill’s Science Diet Dog Food Recall June 2014 (6/3/2014)
To learn why our ratings have nothing to do with a product’s recall history, please visit our Dog Food Recalls FAQ page.
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A Final Word
The descriptions and analyses expressed in this and every article on this website represent the views and opinions of the author.
The Dog Food Advisor does not test dog food products.
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Each review is offered in good faith and has been designed to help you make a more informed decision when buying dog food.
However, due to the biological uniqueness of every animal, none of our ratings are intended to suggest feeding a particular product will result in a specific dietary response or health benefit for your pet.
For a better understanding of how we analyze each product, please read our article, "The Problem with Dog Food Reviews".
Remember, no dog food can possibly be appropriate for every life stage, lifestyle or health condition. So, choose wisely. And when in doubt, consult a qualified veterinary professional for help.
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Notes and Updates
05/19/2015 Last Update