Grew up with hunting dogs around a lot. They would sometimes have problems early in the season with pad wear, but would recover with a little time off. It seems that they would build up pad thickness just like my bare feet in summer.

Check your dog's feet regularly. If you see signs that the pads are thinning, reduce (or stop) the distance for a few days. There are also boots and potions to paint on a dog's pads available from some hunting supply stores.

Bravo for you taking your dog running! Your pet will have a longer, happier life for it. And, most likely, be better around the house for it.