Pug, Struvite bladder stones

Question
I have a four year old male pug (I also have a four year old male Chihuahua)who I am currently treating for Struvite bladder stones.  My vet has put him on Clavamox for the infection and Science Diet s/d to dissolve the stones.  This seems to have worked.  

When we finish treatment (in a week, we're in week five now) she wants me to put him on Science Diet c/d as a maintenance diet to prevent more stones from forming.  I am not a fan of Science Diet and would rather find a more nutritional food which would accomplish the same thing.  On a side note I am a member of my local humane society and we always try to treat our animals as naturally as possible.

Prior to being put on the Science Diet s/d I had him on Nutro Max dental care dry food with a bit of canned lamb and rice.  This is what my Chihuahua is still eating.  My Pug weighs about 20 - 22 pounds, and my Chihuahua weighs about 4.8 - 5 pounds.

What food/diet would you recommend for my Pug to prevent further Struvite stones from forming?  Would you recommend the same diet for my Chihuahua?

Thank you,
Lindsey

Answer
Hi Lindsey,

Well, this is interesting, since struvite stones are not wellknown to dissolve through diet alone and are usually surgically removed. That said, restricting some mineral in the diet, and maintaining a slightly acidic urinary ph - around 6.0 - 6.5 - as well as preventing recurring infection, are all helpful as aids to ensuring the crystals don't develop into stones. Hill's foods are formulated with these goals in mind, so they are probably the best available in terms of symptom control. In terms of ingredients, I agree with you they are definitely not the best around.

So this places the consumer between a rock and a hard place; either you use the poor quality, but well formulated Science Diet, or else you make your own food and use better ingredients, but the formulation may be all wrong for your stone-forming dog. For me the lesser of these two evils is to use the Science Diet. (I personally formulate diets for dogs with these conditions, all the time, but having a consultation is a personal choice). What you need to know is:

1) Struvites almost always develop in alkaline urine, so we want to *slightly* acidify it, which usually means a bit more protein in the diet. Using VitaminC can cause the ph to swing too far in the opposite direction, and you have part of the set-up for oxalates to develop. I recommend using a ph strip from the drugstore to monitor the balance, and always check with your vet if you see it is off in either direction.

2)The vast majority of struvites occur in conjunction with a bacterial infection; using cranberry can help prevent recurrence. For a small dog I would suggest 250 mgs of a pure cranberry extract, which is usually in capsule form. Omega3 fatty acids in the form of fish body oil can be helpful in reducing overall inflammation.

3) A home made diet is ideal but I don't recommend you attempt this on your own. There are many recipes floating around the Internet but most of the ones I've seen are not nutritionally correct. For example, many novices will restrict magnesium for struvite formers, but it's better once the dog is past the acute stage to provide adequate,  but not excessive magnesium. Magnesium is a required nutrient and while it should not be fed to excess, a deficiency of it will create other health issues. Dietary magnesium needs to be correctly monitored. I personally restrict it during treatment, but resume adequate levels once the condition is cleared up.

As you can see from this article, it's not dietary magnesium that causes struvite in the first place; the urine is saturated with phosphate and magnesium as a result of the bacterial presence. Once the bacteria is cleared up, the issue is usually resolved:

http://vettechs.blogspot.com/2005/05/so-your-dog-has-struvites.html

Of course, excess dietary magnesium is only going to make this worse. So as always, a correctly formulated home made diet is gold standard, but since this may be challenging for you, I would stick with the SD. FOR NOW. You should be able to switch to a premium quality food like Canidae in the future, struvites are not a condition like other uroliths which require lifelong dietary manipulation. Your first goal is to prevent the recurrence of infection.

I would have to evaluate your other dog as an individual to ascertain what type of diet would best suit him. My own preference is always for a properly formulated home made diet, using cooked or raw foods as appropriate, and if this isn't possible then a premium quality commercial diet with supportive supplements such as fish oil. In the case of your Pug, it's a veterinary condition and therefore I'm really only comfortable offering pointers, unless I were working with your in a professional capacity.

I hope this helps a little! Feel free to ask anything I may not have made clear.
Catherine