This is what my grandpa said about dogs back in the 30 and 40's he would use one or two dogs to bay up groups of hogs and ride his horse in and pick up the shoats with a rope cut em and mark em and the dog would never have to touch the hogs. The horse would watch for the sows and put a foot in her ribs if she got to close. This was around Woodville Livingston area. If a dog put teeth on hog he culled it.
BarW, my Grandpa tells me the same about them Free ranging hogs in the lufkin area when 59 was a one lane road. a piggin string is what they used to pick up the pigs from the ground into saddle. He also has other good stories too!