Before you buy a bag of expensive dog food from your vet, please ask him/her how many hours of canine nutritional training he/she had before graduating.
Ultimately, whatever you feed your dog is up to you. I have heard of many dogs that have done fine on Ole' Roy. But I sure wouldn't feed it to mine. If you want to listen to your vet, have at it. My vet doesn't necessarily agree with my dogs eating raw, but now that he has looked into it a bit more, he is much happier about it.
Ole' Roy, if I am not mistaken, contains meat by products. This can include the meat from animals that have been euthanized at shelters although that is less common now days.