Our black cat had cartilage issues and they did suggest hip replacement surgery, we declined and she lived a long and happy life. She still chased the other cats around but for very short distances.
Depending on what you pay at the vet, there can be other alternatives. I buy my prescription foods at a pet food store which has vets there. So they sell it to me without asking anything. I use Royal Canin which is the equivalent to "kitty crack". Very addictive stuff, they love it.
I see how you got them to live now. It takes someone with a lot of time and care to raise ones that small. We only know of one person who is capable and has the knowledge to do it. We have had to spoon feed only one foster. We ended up having to adopt her as she became a really big bitch at adoption and made herself unadoptable. At home she is really sweet and nice.
Ok, enough. I went to St. Marys college today and shot this with the 300. They were playing Pittsburg and beat the crap out of them. I know nothing about Rugby but you can get some really good pictures.
Actually I do know something about Rugby. They still play while one of their mates is lying on the ground in agony with an injury.
2000 740i-Annalisa and 2008 335i-Weebl. Weebl may wobble but has DTC
2012 X5d in Sparkling Bronze ( The Ultimate Cat Carrying Machine):2017 A3