Proestrus: The period immediately before estrus in most female mammals, characterized by development of the endometrium and ovarian follicles.

Professional Handler: A person who conditions, trains and exhibits dogs for a fee.

Professional Trainer: A person who trains hunting dogs and who handles dogs in field events.

Progesterone: A steroid hormone, C21H30O2, secreted by the corpus luteum of the ovary and by the placenta, that acts to prepare the uterus for implantation of the fertilized ovum, to maintain pregnancy, and to promote development of the mammary glands.

Progressive Retinal Atrophy (PRA): A progressive degeneration of the retina that is inherited.

Prominent Eyes: As seen on Pugs, a big, round projecting eye.

Prong Collar: Collar used for training dogs. It has metal pieces on it that pinch a dog. It is against AKC rules to use this type of collar on the show grounds. Also called pinch collar.

Pug: A small sturdy dog of an ancient breed originating in China, having a snub nose, wrinkled face, squarish body, short smooth hair, and curled tail.

Pump Handle: Long tail, carried high.

Puppy: A dog under 12 months of age.

Puppy mills: Term used to describe a facility that breeds purebred dogs for profit with no regard for the breed standard, temperament, genetically linked defects, socialization or the dog's overall health and welfare.

Purebred: A dog whose sire and dam belong to the same breed and who are themselves of unmixed descent since recognition of the breed.

Put Down: (1) To prepare a dog for the show ring. (2) A dog unplaced in competition. (3) To euthenize a dog.

Pyometra: An accumulation of pus in the uterine cavity.