I am not a fan of dog parks. Ask the folks at your local Canine Emergency Centers and they will likely tell you, as did mine, that they see a large number of injuries each year as a result of dog fights at such parks. Why is it that humans insist their dogs must love and play with every other dog they see, when it is extremely unlikely they feel the same way about other humans? Where did this concept of dogs as Buddist monks come from? I find dog parks to be the salve of the yuppie conscience. By parking themselves on the bench with their Starbucks double latte while their pup gets rolled repeatedly by the bigger dogs (and gee, doesn't that just seem like fun?) they feel that they are "socializing" their dog and giving it exercise; the one-on-one time they are too busy to make out of their own schedule.
Not to mention the concentration of disease in one small area of earth. There is no check of vaccination or worming records, and your dog is walking through the remainders of whatever thousands of dogs walked that area before him, all in one little fenced in area. Many parasites live on in the soil and you have absolutely no way of knowing whether the cute puppy who was just playing there, went home and promptly died of parvo. I will never forget a person I worked with who said his son had come home to visit and brought two dogs, and that he had to take them to the dog park because they had worms... and he didn't want that in HIS yard!
Those are pet dog reasons to avoid dog parks. For those with working dogs, dogs who need a relationship with their human partner, a dog park can sound a death knell for all things good.
The first is that your dog should look to you as its protector and know that you will never intentionally place it in harm's way. You cannot possibly know all the dogs who might appear at the park, nor the responsibility of their owners. Would you lend your car to those strangers? Then why place the life of your dog lower on the rungs of importance?
Dog parks are primarily a place for humans to socialize. To your dog, you should be the most important person in his/her life~ the giver of all good things. We cannot possibly play as well as another dog, and we do not want our working dogs to decide that seeking out the companionshp of other dogs is a better choice than us. When we are with our dogs, the contact is interactive and engaging; we never stand around and ignore our dog's behavior, or pass up opportunities to reward and shape it properly.
At a dog park you surrender your opportunity to reward your dog. Toy play is likely to incite a riot. Throw a ball and you will have a race between labradors, and if your dog is not the fastest one, he will soon stop chasing the ball with the directness and gusto that you require for competition. Additionally, with other dogs hot on his heels he will be less likely to make a fast pick up and direct return. Using treats can become a fight between participants who threaten your dog over the pieces dropped.
You will be a fair and responsible owner if you commit to spend time with your dog, instead of giving that over to other dogs. The time you spend with your dog in interactive (emphasis on *active*) play that teaches simultaneously, is the best gift you can give. Your dog will look forward to spending time with you, instead of saying "just drop me at the gate."