Field service vets did a presentation on it during a food-animal meeting here last year.
At best, their 'results' looked like 'damning with faint praise'... and discussions with other vets who heard the same presentationwere kind of like, "Uhh...I'm not sure why you'd want to bother with it?" , so I"m guessing I didn't misinterpret what they presented.
Positive effects that they showed were so minimal, that I'm not sure its worth using.
That said, it was several months ago, and my memory may be fuzzy...