There are few meat herds where CL is NOT present. It's extremely common because it doesn't matter to meat producers. It's a skin disease that gets trimmed off with the hide. If it's internal, then, yes, the carcass is no good.
I'm glad that at least you are putting her to good use. So many people think CL is the plague and off anything with a lump immediately. I inherited a positive herd, and while the abscesses are ugly and a pain to clean, my herd is happy, otherwise healthy, and gives me lots of tasty milk. I understand now why other countries treat it like a cold! But if your doe has other health issues, I understand why this is the last straw for you.
You did what you had to do.....it would not have been fair to keep her.
I had a sheep with it last year and even if I had a gun,there's no way I could..... I have found out that the local dog's home will euthanise sick animals for £15.....they just go off to sleep on the end of the needle.
I could hardly drive home through the floods of tears,though.
So....good call,even though it hurt.