What are the advantages and disadvantages of using animals as organ donors?

I am assuming that you are talking about using animal parts for organ transplants on humans. Having said that, there are at least a couple of snags that could come up. The body could reject the organ because of some forseeable or unforseeable problem, and the organ could reject the body because of some compatibility issue. The organ could be too weak or to strong for the body Or on the otherhand the blood could nto match with the organ. I hate wiki its rubbish.Do one(Y)