Sorry I'm just getting so annoyed trying to remember it and no one else seems to. It's an animated children's movie about a dog, however I don't think it was that well known. I can only remember the start, when a litter of puppies was about to be thrown into a river to drown, but they float to the side of the stream. The main kid in the movie finds the sack and opens it and one of the puppies jumps up and licks their face.
I known it's vague, but it would really mean a lot of someone could help me out so I don't feel like I'm going crazy

hmm. The only thing I can think of is milo and otis, and that's not animated... I don't know what it could be. It's horrible to go without knowing the name of a film you love! I wish I could find mine =(

The only animated dog movie I can think of is Fox and the Hound. I haven't seen it in a good 15 years, so I can't remember if that's the one. Good luck