Have you ever wondered why there is so much uniformity in well-bred dog breeds in both looks and temperament?  It is because each American Kennel Club (AKC) recognized breed has a breed standard, or description of what each breed should look like and the type of abilities the breed should possess be it a guard dog, herding dog, retriever, etc.  This is the template that reputable breeders use when making breeding decisions.
 

The Nederlandse Kooikerhondje Standard describes the desired physical characteristics, temperament, and working ability for our breed. These traits were originally chosen to define a dog of a size and personality that enabled it to be an efficient tolling companion in the eendenkooi, vermin hunter, and alarm dog.  It is that intelligence and trainability that have gone on to create a breed that can excel in so many activities as show and performance dogs in all AKC sports, and beloved family companions.