My boy recently had a raging ear infection. Turned out to be a psuedomonas bacteria and a yeast infection. Psuedomonas is particularly difficult to eradicate because it can become resistant to treatment so it's important to try other treatments if the first fails to clear it up.
I had to give two (10 day) rounds of oral antibiotics (Baytril) and daily treatments with Otomax and Conofite lotion and finally Neopolydex, an opthalmic (eye) drop, before it cleared up. It was so painful for this gentlest of dogs that I had to muzzle him to treat him.
Not being satified that it was simply an ear infection, I also asked for a complete blood count (CBC) and a complete thyroid panel (not just the in-house vet clinic test). The thyroid panel had to be sent to a lab in Michigan. I suspected hypothyroidism .
Indeed my dog was hypothyroid. Ear infections are one of many symptoms of thyroid problems so my guess was a good one. We have had no more ear problems since we started thyroid medications.
My point in this story is to not give up and if you are having chronic ear problems start asking about underlying causes or complications. There are many things that can cause ear infections; disease, allergies, foreign bodies, mites, etc. If you are not getting answers or the problem doesn't get better, get another opinion. It is not humanly possible for all vets to know everything about all dogs. Keep pressing for answers if the problem doesn't clear up. I had to nearly harrass my vet (who I like and respect) into trying different things and looking for causes.
For heavy coated dogs with pendulous ears, owners can keep the fur under the ear (on the side of the dogs face; his upper cheek, if you will) trimmed short. While this won't prevent ear infections, it will help with air circulation in an area that is typically warm and damp. Also learn how to trim up the ear margins. Make sure that you brush and comb that area on a regular basis and check the ears frequently for signs of infection. Lots of gunky brown material is not normal. Smelly ears are not normal. Pink or red or oozing skin under the ear flap is not normal. If your dog rubs his head frequently or cries when scratching, it's not normal.
If you swim your dog a lot, you will probably have some ear problems. Check them frequently during the swimming season. Dry them after swimming each time. Have your vet show you how to clean and flush ears without injuring them. Don't give up on fixing this problem. Repeated ear infections can lead to scarring of the ear canal or possibly puncture of the ear drum and middle ear infections. Untreated or chronic ear infections can lead to deafness if not managed or cleared up.
Also, your sister may have a point. Hygromas, which are fairly common in Saint Bernards and Mastiffs, are very uncommon in Newfs. In fact, I have only seen one other Newf with a hygroma out of hundreds of Newfs that I have been around at shows, regional club events and pet owner gatherings. Your pup is exceptionally large for a Newf of his age so it wouldn't be surprising that his over sized body at his age is the cause. I don't mean that as an insult or to be hurtful, it's just an observation. You have already determined that he is not overweight, just over sized. You may want to address his size with your vet and ask about other possible problems that being extra-large may cause. There may be skeletal issues or organ problems that you should watch for.
