There are 2 newsletters that I subscribe to that I highly recommend for good information regarding your pets. They are the only 2 newsletters that I keep every issue and put them in a binder.
The 1st one is Your Dog and is from Tufts Cummings School of Veterinary Medicine
http://www.tufts.edu/vet/publications/yourdog/ and the 2nd is
The Whole Dog Journal
http://www.whole-dog-journal.com/
You can go to both websites to give you an idea of some of their topics.
I have not had a lot of luck with dog magazines for the most part because they are to full of advertising for me.