As noted in previous posts about Cosmo’s food, I use Royal Canin Urinary SO (moderate calorie) canned food as an oxalate-free source of vitamins and other essential nutrients that are below the RDA in his homemade food recipe. In many ways, I use Urinary SO like a “Balance IT” additive. One problem with an oxalate-free diet is that you can’t use green leafy vegetables or some root vegetables. These are good sources of vitamins and minerals. Using the Urinary SO gets around that problem and limits the number of chemical additives I have to use.
Recently I discovered that Royal Canin changed the formulation of their Urinary SO (moderate calorie) canned food. For the most part, the new RC recipe is an improvement since it has less fat (47% old vs 26% new); however, it also has fewer calories per gram (0.9 vs 0.8%) and each can contains fewer calories (326 vs 282), which makes it even more expensive. Notably, Royal Canin did not effectively notify consumers of this change, and the new label does not declare any change in the formulation (e.g., no statement like “new improved formula”). Of course, some of the changes are shown in the nutrition data provided on the label. It just doesn’t jump out that there has been a significant change.
One reason I used the Urinary SO in the past was that the company provided a rather complete list of “typical analysis” data for the various nutrients in the food. This made it easy to define the food in PDD. I contacted RC, and they sent an abbreviated list (41 ingredients old vs. 24 new) for the new formulation. Fortunately, it included most of the nutrients of concern. So I adjusted the Urinary SO “food” in Pet Diet Designer to reflect the new analytical data. I assumed the amounts of nutrients I didn’t have analytical data for hadn’t changed significantly. I continue to use 125 g per day of the Urinary SO in Cosmo’s food, which now contributes only about 100 calories to his daily 572-calorie requirement (17.5% of calories).
Because the Urinary SO now contains less fat and fewer calories, I had to adjust the homemade recipe with the help of PDD. The balance screen for the new recipe is shown below. I added some corn oil to bring up the fat content and calories. I also increased the turkey and bone meal and reduced the amount of rice by small amounts. The result is a recipe with similar protein, fat, and carbohydrate content (as a percent of calories) to the previous recipe. See the PDD nutrient report below.
Since the Urinary SO now contains less zinc, I added the contents of one 220 mg zinc sulfate capsule to the 21-day batch recipe. As I mentioned previously, nutritional supplement capsules meant for human consumption provide a good source of many minerals and vitamins for homemade pet food. They are relatively inexpensive and do not require accurate weighing of small amounts of the additive. If you use a bulk chemical as an additive, you usually need to calculate the amount of the specific nutrient in the chemical (e.g., the amount of zinc in bulk zinc sulfate). This information is almost always listed on the supplement capsule label (e.g., 50 mg of zinc in 220 mg of zinc sulfate).
Zinc Sulphate supplement
Defining a supplement capsule with the PDD food wizard can be tricky. Using zinc sulfate capsules as an example, when using the wizard, pick the common measure rather than the per 100g option. Define the amount as “1” (for one capsule), then define the measure as “capsule.” The “measure weight” is the weight of one filled capsule. Normally, I weigh 5 or 10 capsules together to get an average weight for one capsule. Once this is done, I enter the amount of zinc in one capsule, which is 50 mg (from the label). Note that it is not 220 mg, which is the weight of zinc sulfate in the capsule. Then I save and close the wizard to complete the zinc food entry. Be sure to hit “refresh” before searching for your new entry in the food database.
When you go to enter the new capsule ingredient into your recipe (balance screen), PDD will initially enter it as 100g of capsules. But on the far right of that entry, a drop-down menu lets you select capsules rather than grams as the unit of measure. I find it easier and clearer to work in “capsule units.” Once you select capsules and adjust the quantity to give the correct amount, go back to the recipe and refresh it to bring the new ingredient into the recipe. Then save it. If you refresh before changing the balance screen from grams to capsules, the recipe will show grams of capsules in the batch report, and I don’t think there is an easy way to change this. That is not a big problem. Just weigh out the number of capsules needed, but remember the weight is for filled capsules, not the powder in the capsules.
If you use capsules as the unit of measure, the balance screen will usually show a fraction of a capsule for the daily amount. But the batch, which for us is a 21-day supply, will show a more usable value. I don’t worry about getting it exact. I round up or down as needed. For example, the batch recipe calls for 5.25 capsules of copper citrate, but I use the contents of 5 capsules. To empty the capsule, pull it apart. Wearing surgical gloves helps you grip the capsule ends. I discard the empty capsules and mix the emptied powder well into the recipe. As the recipe shows, I use capsules to supplement the other foods with potassium, magnesium, zinc, iodine, copper, and fish oil. The balance screen shows that the RDA is not met for zinc, even with the addition of one capsule of zinc sulfate. Since it is a new ingredient and zinc sulfate can cause stomach upset, I tried adding just one capsule for the first batch. I haven’t seen any problems and will add two capsules next time. That amount will exceed the RDA for zinc.
We continue to give Cosmo “soup” three times a day to dilute his urine and hopefully decrease the chance of oxalate stones forming. See the previous posts for more information. The new recipe also continues to use citrate to make his urine less acidic, which is also thought to inhibit stone formation. So far, Cosmo really likes the new Royal Canin food and only leaves a few rice grains in his bowl (and on the floor!).
Balance screen for revised recipe
Nutrient Report for new recipe
