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Ask the Veterinarian/C/D diet alternatives


QUESTION: Good evening,

My 2.25 year old male neutered cat (up to date on vaccinations) experienced difficulty urinating back on March 20th.  The vet gave us a round of clavamox and dry science diet c/d, which he ate for one month and was still on when, on April 21st, he stopped urinating again.  Additionally, from the date of the first incident, he has been drinking only distilled water, as we are on well, and he is a very good and regular drinker.  He free eats and maintains weight well, so we have not previously considered switching him (and therefore the other four, healthy cats) to a wet diet.

At the second of the two incidents, in April, he blocked up so severely that he was with the vet for a week before he could keep his cath out.  They found no crystals, just some blood, and did a repeat urinalysis at discharge to the same result.

My question, after all that, is if the Science Diet is really the best option.  We don't know the root cause of the blockages, so it doesn't  make sense to give up on the C/D formulation entirely in case it helps, but the ingredients look AWFUL compared to what I normally feed them.  Is this really the best choice - rice and corn and meal?  Is there a different commercial diet out there that ALSO alters urine pH, or deters crystal formation, etc., but that has a better quality composition?  And if we had two back to back incidents a month apart while ON the c/d diet, and with no crystals present, how much influence can I assume the c/d diet is having?

Of course my vet recommends science diet, like most vets that sell it will, and I back that until his system has settled out at least.  I just wonder if there is a healthier choice once he is better.  We have a recheck in a week that will let us reevaluate his condition and look for crystals again - I won't be changing anything between now and that point at least, so as not to add stress.

Thank you in advance for your time!

I know the ingredient listing for C/D doesn't look to appealing, but it really has only a few ingredients in it, which helps make it a stable diet.

Brewers Rice, Corn Gluten Meal, Chicken By-Product Meal, Pork Fat. These things sound gross to us but let's break them down. Brewers rice is a high quality rice that is high in protein. You don't want a cat that has urinary problems eating a high meat diet because that can cause some issues with urinary health. The rice helps maintain a better PH for the urine.
Corn gluten meal is highly digestible, cooked corn that is grown here in the USA for food only. It's like maize, which is the corn that the Native Americans were growing when the Mayflower landed here. Once it is cooked and ground up, (hence the meal) it is very easy to digest and provides a high-quality protein for the cats.

Chicken by product meal is simply de-boned chicken parts like the back meat, wing meat, leg meat etc, that is ground up after it's cooked. It has NO feather, bones, beaks or feet in it. Science Diet will not allow those parts in their formulas. This also provides the protein that obligate carnivores like cats need.

The rest of the ingredients are vitamins and a few amino acids that help maintain the proper PH for bladder and urinary tract health.

From the Hills site on the benefits of this food:
Prescription Diet® c/d® Multicare Feline is formulated with the following benefits:

   Controlled levels of calcium, magnesium, phosphorus and oxalate to help limit the building blocks of crystals and bladder stones
   Rich in fish oil - an excellent source of Omega-3 fatty acids - to help promote healthy skin and a shiny coat
   Added potassium citrate to help interrupt bladder stone formation
   Increased levels of vitamin B6 to help decrease oxalate formation
   Low sodium to maintain normal blood pressure
   High in antioxidants (Vitamin E and Beta-Carotene) to control cell oxidation and promote a healthy immune system

So the ingredients that look dubious to you are all formulated from years of veterinary research on "what food promotes and maintains" proper bladder and urinary tract health in cats.

This food has been tested for decades on real cats, not just formulated and packaged. So Hills knows that it works.

Some cats are born with smaller urethra's and have issues with UTIs (Urinary Tract Infection) all of their lives. I experienced this myself with a male cat I had that plugged a bunch of times (and almost died). That was before I fed my cats Science Diet. Once I started feeding it, NONE of my male cats EVER had a single UTI at all.  

The fact that they didn't find any crystals the second time shows that the C/D is working, but your cats bladder is still irritated and friable from the first go around. So many other factors might also play into UTIs, like bacteria, irritants from litter box crystals,stress from other pets, or new things, physical build of the cat (urethra size etc.). Even after decades of research on these diseases, there is still no concrete answers on what causes them.  

Now, my question to you is this: what are your other cats eating that he is getting in to? It's pretty hard to maintain a cat with a sensitive UT if he is eating even ONE nugget of another kind of food. It doesn't take much to set them off.

Most of the time the owners don't even realize that the cat is getting into the other cats food, but that is usually the cause of the setbacks.

So before you put C/D on the chopping block, look around and see how and where he might be sneaking a nibble or two of the other food.

For more information on Prescription Diets and C/D check out Hill's website.

Be sure to read the reviews of the food as well from pet owners just like us!

I hope this helps some. Let me know if I answered your question at all!

---------- FOLLOW-UP ----------

QUESTION: Thanks for the quick and thorough response!

I had to switch everyone to the c/d when I swapped him, so there were no other foods to be accessed in the house, including treats. He is isolated in his own room until he stabilizes to continue it (and to monitor his personal box), but I have a baby coming, so we will not be able to maintain that permanently, unfortunately.

Could you elaborate on the negative impact of meats on a urinary diet, please?  I am very intrigued by that!  Additonally, my question was primarily if there were any other diets catering to this issue?

Thank you again,

I'm not saying that meat is bad but it's more an idea of having easily digestible proteins more than less meat. Some plant based proteins are just easier to digest.

While the idea is still kicked around about the urine being more acidic than not, I don't know that they have ever found that to be helpful or not either.

More meat causes more acid. But it also depends on the type of meat as well. Again, chicken is easy to digest so they use that instead of beef or pork, both which are major allergens to dogs and cats.

As far as any other diets like C/D you might find some along the other prescription lines of CNM (Purina) or any of the other brands that must be bought at the vets.

The reason for this is because these foods are formulated specifically for this problem and have added ingredients, such as potassium citrate and dl-methionine to help with the reduction of crystal formation and bladder health. DL-Methionine is an amino acid so it's all natural.

These other foods will cost as much or more than C/D. It's not a good idea to switch food over and over as it can cause digestive issues and your cat doesn't need that on top of having a bum bladder right now.

Keep them on the C/D until he gets well then if you want you can slowly transition them to another less expensive Science Diet such as the Indoor Cat formula which is formulated for cats like yours and is specifically made with bladder health in mind.

Congratulations on the baby!!

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Jana Connell RVT, CVT


PLEASE READ BEFORE SUBMITTING TO ME: I am NOT a vet and do NOT diagnose diseases. That is only for a licensed Veterinarian to do. I will give you suggestions and steer you toward calling your vet for help. You can call the vet's office and talk to the technician there or the vet at times. Don't be afraid to call them! If you have a serious issue with your pet please post it to one of the veterinarians in here- I will tell you the same thing in my answer. IF your pet is injured or in an emergency situation, CALL YOUR VET- Do not wait and post in here. Just call the vet's office and get them in to see the vet right away. Critical treatment time is lost if you seek answers here when you should have your precious pet at the vets!! Don't sit at home waiting for an answer when your pet is critically ill or injured!! I can answer most questions about small animal and wildlife care as well as small animal nutrition. I can also answer questions about all phases of dental care for small animals. I DO NOT answer questions about birds (unless it is wildlife or songbirds) or HAMSTERS/GERBILS/CHINS/GUINEA PIGS/REPTILES/FROGS/RABBITS/PET BIRDS OF ANY KIND so please submit these questions to the appropriate sections. I, as well as other experts in here, do NOT do homework questions- that is for YOU to do! Please respect these rules for all of us. Thanks!


I have over 35 years experience in the field of veterinary medicine. I specialized in small animals and did wildlife rehab for over 25 years, mostly raptors, squirrels and opossums. I am a Small Animal Nutritional Consultant with 6 certificates from Hills Pet Foods, CNM and Purina. I also specialized in Small Animal Dentistry which is a field I truly love.

Audubon,World Wildlife Federation, American Society of Veterinary Dental Technicians.

Licensed with California and Oregon, RVT and CVT. Certified Veterinary Dental Technician Have over 550 logged hours of Continuing Education Credits(that means I keep up to date!).

Awards and Honors
Nominated for Expert of the Month for the last 5 years.

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