I have never had the Anal Gland problem with Oscar but my Shih Tzu used have to go to the Vet every 30 days and have it done..
I could tell when she needed to go because she would lick herself constantly..
My Vet advised me to try a different food. I tried several different brands and she does great on a grain free limited ingredient with chicken or turkey..
Lamb and Fish seem to bother her so I stay away from those ingredients..
Kaiah has not had to go to the Vet for Anal Glands for almost a year..
Of course all dogs are different so this may not be a solution for everyone