Never used it, but have heard it works.
I think it was developed by a fellow around Bozeman, Mt. a long time
ago.
What do you intend to use it for? Bloat in cattle?
When we had so much trouble with Pulmonary Emphasema
(some call it asthma) in cattle, we did hear that Silent Herder
helped with that as well.
But we have never used it ourselves.