Keep in mind to much of many vitamins is as bad or worse then not enough. Personally, as long as the dog is on a high quality food suitable for the breed and lifestage, I see no need to add alot of "extras" to the diet.
A retired vet, on another forum, highly recommended Pet Tabs as having the best vitamin makeup and uses them as treats.
Sorry Barbara, have to disagree strongly here, they were not used as treats, that makes it sound as though they were used many times a day, every day, which is wrong.
My vet recommends them and I use them for my oldies, half a Pet Tab once a day, have done for some years and as they are or have all reached their teens, think they must have done ok!