We have a Pyr and we raise quarter horses. Boomer gets along great with and around the horses. We stand a stallion and have a lot of outside mares coming onto the farm to be bred. There has been no problems. When I make my midnight check on my broodmares Boomer goes with me and watches from a distance. Danelle <A HREF="http://www.quarterhorses.com/jdg">JDG QUARTER HORSES</A>