ABSTRACT
Dog breeds are unique in their coat conformation and quality. Newfoundland dogs have a long and fine hair coat, and clipping may induce changes in newly grown hair. This study examined structural changes in the skin of Newfoundland dogs following clipping. Dogs included in the study had visible coat changes following clipping that appeared as loss of gloss, increased scaling and textural changes. The control groups consisted of two groups of dogs that had never been clipped: Newfoundland dogs served as within-breed controls, and long-haired dogs of other breeds served as between-breed controls. All dogs were healthy with no history of dermatological problems. Two skin biopsies were taken from each dog and evaluated for predetermined parameters. A total of 41 samples were examined: 11 from clipped Newfoundland dogs, 16 from unclipped ones, and 14 from dogs of other breeds. By histopathology, the clipped dogs had a thicker cornified layer (P=0.006) and smaller sebocytes (P=0.022) than the unclipped ones. Newfoundlands had larger and more epitrichial sweat glands than other breeds (P=0.0002, P=0.036, respectively), and those were not affected by clipping. These results suggest that hyperkeratosis and decreased sebocyte size may explain the observed coat changes following clipping in Newfoundland dogs.