what breeds are best as service dogs
This is a very complex question. Traditional breeds for service dogs have been German Shepherds (GSD), Labradors, and Golden Retrievers. But nowadays the use of unusual breeds has exploded. Mastiffs are used for mobility work. Chihuahuas are used for diabetic or seizure alert dogs.
Note: As author, I have decided to avoid gender preference by referring to a dog as him, but either gender can be a fine service dog. BREED CHOICES. Many breeds of dog have been experimentally drafted into the assistance dog field. The most popular for service dog work are the Golden Retriever and Labrador Retriever. Samoyeds, Smooth Coated Collies and Rough Coated Collies are some of the newer breeds that are showing promise.