I forgot to add we also used tarsal glands, urine and untanned hide to help in the training. It didn't take much training.
Stay away from "over breeding" dogs like a chocolate that came from a long list of chocolates. A chocolate (which mine was) is the smallest slice of the genetic pie as far as labs go. Overbreeding for color is a problem. They can have heath problems (ears, eyes and nose to name a few) not limited to poor scent ability. Mine came from a black dame and a yellow sire. Neither had hardly any chocolates in a five generation pedigree.
Lots of breeds will do but the lab can do duty as a tracker, retriever, protection (great bark but too lovable to protect sometimes), pet and a great companion.