When my Kitty was spayed... she would not keep the E-collar on. Every time I finally got it on her, she found a way out of it. To prevent her from licking it and getting it infected, I bought a size 0/3 months baby onsie at the dollar store and cut a Pee/Poo section around the middle button at the bottom and just put it on her. Now her incision can heal and she can look adorable at the same time :)
