I don’t know but I had to look it up because I just got my first dog, she’s a mix and only 7 months now and I don’t know if this would be an issue, I’m kind of new at the dog thing… but I looked into it because I’m kind of really, really hoping that regularly “expressing” my dog’s anal glands is not going to be a big part of my future, but I did find this article, it’s maybe a little NSFW or not for people uncomfortable with full color illustrations of dog anuses, the vet speculates that it’s becoming a more frequent problem possible because of modern diets for dogs. Maybe it can be correct with the proper diet. Hopefully someone knows more than me because I am interested in learning about it too as a new dog person.