10 month old Newf with constant diarrhea

Question
My 10 month old new has had diarrhea since arrival at 2 months.   Back then she was on the raw food diet. (Saw her go at the breeders and it was healthy looking.) After 2 months, thinking Raw wasn't going well, I transitioned her to Orijen puppy which was the old other option recommended by her breeder.  The diarrhea continued. A meal of Rice and ground beef caused vomiting. She's been to 3 different vets. The first 2 seemed to accuse me of improper care with the raw diet. The 3rd treated for giardia 2x and eventually sent me home with W/D. No diarrhea on the W/D but the dog pooped constantly and begged for food all the time.  The W/D, in addition to being expensive, goes against everything the breeder suggested, so I am now at a loss of how to proceed.
The dog's coat is shiny and beautiful -- although not full and long the way a Newfie coat ideally should be. She is not scratching or fussing.  Her skin looks great.  She does seem to drink a lot. As of today, I am measuring her intake. It expect it to be in the gallon range (on a below freezing day.)
I'd appreciate a suggestion on how to proceed and whom to trust. Thank you.

Answer
Hi Bonnie,

Well first of all, I feel you can trust ME,  I've studied and worked in this field for many years and have a strong following that includes many vets, vet techs and breeders; I am deeply committed to this work and to helping owners provide the best nutrition for their individual dog. This is my livelihood and my passion, so I like to think I can point people here in the right direction. I don't promote a diet style(Raw, kibble, cooked) because many options can work and each dog is an individual; what I do emphasize is respect for the science - in other words, working to provide the nutrients a dog needs at all life stages using the best and most up to date research we possess. So I will be quite blunt here and do my best to help you resolve this problem in as expedient a way as possible.

So - when you say your puppy was on a "raw diet" from weaning to four months - can you elaborate? What kind of raw, was it a commercial product or a home made  diet? All the term "raw diet" tells me is that the food isn't cooked. Many raw feeders are very relaxed about nutrient content, going on the philosophy that since it's "natural" it has to be good. Sadly this is not the case and it is NEVER the case EVER with a giant breed puppy. So I am quite concerned this pup had a "raw diet" until four months - this is a critical growth period and only very knowledgeable, very experienced raw feeders should attempt to do this.

Although I think the term "improper care" is harsh, I have to say that it's very dangerous to try a home made diet of any kind with a giant breed puppy. I know you were trying to do the best for her, and the past is the past, so let's move on.
Has this dog been tested for giardia and coccidia? I see these infections all the time with pups fed raw diets at an early age.
Are you open to a home made cooked diet? I do this for a living and handle extreme cases all the time. I would be happy to develop a diet for your pup using the NRC guidelines for nutrient requirements, and  the fresh ingredients we always like to use for diet whenever possible. If this is of interest to you please contact me at home catlane@thepossiblecanine.com and we can discuss it in more detail (Service information at my site www.thepossiblecanine.com).
If not, i would suggest you experiment with the higher end premium foods such as Acana, and aim for limited ingredients and/or novel proteins as your dog is so clearly gastrically sensitive. but I feel a thorough veterinary check to rule out parasites plus a professional diet are very much in order here.

All the best,Catherine