Hi, I have an approx 8 year old Boerboel, who used to love going for walks. We'd go for up to 2-3 miles per day, at his pace and direction. Then around mid-August, he just stopped wanting to go, and now will only go for car rides. He is not sick or injured in anyway, so that does not seem to be the problem. He's still very active in and around the house and yard, and is very anxoius to go out everyday, but only for car rides. Ive tried new routes near our house, treats, and even driving him to new distant locations to take our walks, just in case maybe he was bored with our usual routes. He'll jump out of the car, walk for maybe 5 minutes in the new location, and then pull me back to the car. He's not even interested in going to off leash parks where there are other dogs with which to play. He just heads back to the car. Has anyone else had this kind of problem with their Mastiff/Boerboel?