@jengosmonkey That is a very interesting link. My girl suffered none of the possible side effects. No lethargy, listlessness, weight gain and her shape remained immaculate till the day she died. But she no longer suffered from IBS.
I have two males together (yep, both unaltered!), a flat coated retriever and a basenji. I was going back and forth with the same things, but I'm a male person. My flat is the oldest, but he is a very soft boy to work around. He has never gone into a fight, because when another dog is growling/getting into it, he backs off immediatly. So I hardly think it's going to be any problems with male/male here. Others might, every dog is different.
when i first got malinois #2, she was down on her pasterns and was about 10-12 months old. I gave her some joint supplements with vit C in them. That combined with good exercise helped. Do you have pic of your boy in a show stack?