I had a line here that ALL got malo, going back to one animal. The oldest was the mother of them all, she wasn't young, I'd say 6 or older without looking at her pedigree, the offspring from here were from 6 months old. After coming here within several months they all came down with malo. I don't deal with malo a lot here, and out of that bunch of animals ( a larger selection) it was only this group related to that female, which to me would be a genetic thing. If it was environmental from either place I'd think that all of the animals would be affected, not just one line.