I dont know how many dog fights you have stopped, but a dog as big as that and if it means it kicking it will do not a lot, especially if its moving around a lot. You may infact do your own dog damage.
Best thing to do is to stop the dog shaking, choke the dog, keeping the dog under slight tension (with someone holding the other dog) untill it releases its grip and then if you feel the need to kick the fecker then kick it, with some stout foot ware or steels.