According to the USDAA, there are over 150 breeds of dogs, including mixed-breed dogs, involved in agility. Some breeds, like the Australian Shepherd and the Dutch Shepherd, are known for excelling at the sport. However, you should not let the fact that you have a Golden Retriever or a mixed-breed dog stop you from trying it. If your dog is playful and energetic, it will probably enjoy agility training.
Dog intelligence is exhibited in many different ways, and a dog that might not be easy to train might nonetheless be quite adept at figuring out how to open kitchen cabinets or to escape from the yard. Novice dog owners need to consider a dog's trainability as well as its energy level, exercise requirements, and other factors before choosing a new pet. Very high intelligence is not necessarily a good thing in a companion dog, as smart dogs can require extensive daily mental stimulation if they are not to become bored and destructive.