We have an older Keeshond dog who has developed this problem as she got older. So we eventually switched her to this dog food:
http://www.thehonestkitchen.com/It comes freeze dried and you have to boil water and mix it yourself. The advantage to this is you can make the food as dry or wet as you need it to be depending on how much water you add to it when you make it.
If we make it too wet the old gal will have loose stools and need medication to control that problem. But if I take my time when making it and add just a little water at a time until I end up with a thick almost pasty very dry concoction the loose stools go away. No medication needed.
I think this may be a common problem with older dogs so I figured this was worth mentioning here.
It is good food too. Human quality. Enough so that humans actually do the taste testing at the factory where it is made.
Don