What I always wanted to know was how likely it is for you to give your goat kid or calf Johnes from feeding it pasteurized store milk or milk based replacer (or powdered colostrum) since it's common practice to do that when you're out of your own tested milk, and not all the Johnes gets wiped out at standard pasteurization temps, and not so many breeders test for Johne's and are willing to share. If animals could get measurable levels of Johnes antibodies from drinking the pasteurized milk, I'd be a bit concerned about drinking it on occasion myself (since I'm a germaphobe).
The conclusion I've come to after trawling too many scientific journal articles and things put out by credible institutions is that it's probably (hopefully) unlikely, but nobody seems to know or want to know for sure...and that's annoying. It's a disease that kills things and shortens the useful life of a certain percentage of animals, and may even affect people. Probably is not acceptable, although right now it appears to have to be.