Diseases of the Integumentary System

Chapter 31 Diseases of the Integumentary System


The avian skin is much thinner and more easily damaged than that of mammals. The layers of the skin (epidermis, dermis, and subcuticular) are the same as in other animals. The horny bill is composed of hard keratinized epithelium and the underlying dermis that is continuous with the periosteum of the mandible and premaxilla. The beak contains sensory receptors that provide for food discrimination and tactile sensation. Claws are also extensions of the hard keratinized epithelium. Some species of birds have a uropygial gland that produces an oily substance for waterproofing of the feathers (African gray parrots and budgies have this gland whereas Amazon parrots do not). This gland can become obstructed and cause a swelling above the tail head in some birds.


The most obvious difference in the skin of birds is the presence of feathers. Several different types of feathers exist, and each has a specific purpose. Feathers are molted by extrusion of the old feather from its base and replacement with new feather growth from the dermis. The newly developing feather is known as a blood feather because it contains large vessels that will retreat as the feather ages. Feathers serve many functions: They give the body shape; allow for flight; provide balance during landing and takeoff; offer thermal insulation; and in some species, provide for sexual recognition. Feathers also provide the beautiful colors that bird owners appreciate. Any topical medications that would interfere with the normal fluffing of the plumage for insulation can cause problems in birds. For this reason, oil-based topical medications should be avoided in treatment of skin problems.



DISEASES THAT INVOLVE THE FEATHERS



Feather Mutilations


Feather picking, plucking, and chewing are common problems seen in the veterinary clinic (Fig. 31-1). They are also some of the most frustrating and difficult problems to treat. It is believed that some of these behaviors may develop from boredom and excessive grooming behavior that gets out of hand (similar to cage walking and other captive behavior problems seen in mammals). In some species—the passerines—feather plucking can be related to aggression, with male birds plucking female or other subservient male birds. In psittacines, feather mutilations appear to be more complex in nature. Feather picking should be suspected in birds that have normal head feathers with varying degrees of body feather loss or damage. The African gray appears to be involved in feather mutilation more frequently than Amazon or Macaw parrots.








Aug 31, 2016 | Posted by in GENERAL | Comments Off on Diseases of the Integumentary System
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