I made these patterns myself, I am NOT a pattern maker so be warned! I tested both patterns myself and they turned out just fine and one of them is keeping my new buckling toasty at night.
Now my goats are sort of small, bigger than pygmy goats but smaller than your average full sized meat or dairy goat. These sweaters will fit a wide range of kid sizes simply because they are entirely out of ribbing so they are self-adjustable and stretchy. As long as they are long enough to cover the baby goat's little bum but not so long that the tummy gets in the way of boys going potty you should be good for just about any size kid.
Also, after trying this on an actual kid I can say that the legs are purely optional. In actuality I don't think I am even going to put legs on future sweaters because they seem to kind of get in his way when he is trying to get up and down. the main thing is to keep the core of the body warm without getting in the way of the baby's ability to move around and do what baby goats do (eat, go potty and bounce).
I've posted the instructions to knit flat first, and the instructions for knitting in the round second at the end of this post.
Obviously these sweaters work well for dogs as well, but I find that the neck is really wide and my dog ends up walking right out through the neck hole, haha!! This does not seem to be an issue with the goat kid, though.
Baby Goat Sweater, Flat Knit Pattern
Baby Goat Sweater pattern, Knit in the Round