Joe: my friend answered your question today and here is his response: "This term refers to having a product such as Borium or Drilltech put on the shoes with a soldering iron or torch. They can also just put a row of weld on them for traction. This is quite common today. Especially in Amish buggy horses. There is also a shoe made with heel and toe cleets made onto the shoe for added traction."
Hope this helps,