Dogs can suffer from a whole host of diseases and other serious health problems. Some of these conditions are inherited, while others are caused by viruses; still others are related to lifestyle and environmental influences.
For the health and wellbeing of your dog, training should really not ever be considered an option when owning a dog. Well trained dogs are more likely to be behaved and listen, be void of behavioral issues, be good in public, and are less likely to bite. Owners also have a much closer connection with the dog when the time is taken to form a relationship through training.
Herding is one of oldest canine activities available. It has real world applications and is still in place for viable farm assistance in many places. For urban individuals, herding has become more of a training activity for competition for those breeds of dogs with natural instinct.