Yes I believe that catgut is made from Sheep intestines.
I don't hate feral Cats or abandoned Cats, I feel sorry for them. Many of these animals were someones pet that they decided to get "rid" of and quite often it is done when the animal is very young. To me that is cruel beyond belief. I would rather put a bullet in an animal than throw it away like useless garbage.
A couple years ago just before Christmas we found a small kitten abandoned near our house, he was living under an abandoned house. This kitten was no more than a few weeks old and there was no way he could have fed himself even if there had been no snow on the ground. All he had to look forward to was a slow, freezing death. I went out 3 or 4 times a day to bring him food in -20 degree weather. In over a month he never put on any weight, most likely using all the energy from the food I gave him just to keep warm. He finally trusted me enough that I was able to grab him and I brought him into my shop where it was heated. Then he started to put on weight