I. BEAK DISORDERS
Anatomic Features
The avian beak grows continuously. It is composed of two jaws: a maxilla and a lower mandible. They are composed of bone and are covered with keratinized sheath called rhamphotheca (rhinotheca for the maxilla and gnatotheca for the mandible). The epidermis is closely joined to the bone and the stratum corneum is very thick. The mandible is connected to the skull by the square bone. Replacement and growth are dependent on species (in large parrots, beak replaced in 6 months).
1. Abnormal growth
a. Nutritional origins: vitamin D3 deficiency, diet with a too high protein rate (frugivorous), soft food.
b. Parasitic origin: beak mite (Cnemidocoptes pilae), in Melopsittacus undulatus.
c. Other origins: genetic, hepatic, viral.
2. Soft beak
It is caused by vitamin D3 or calcium deficiencies.
3. Colour changes
They show an unbalanced diet or a general disorder (Lorius lory, Rhamphastos toco)
4. Beak malformations
a. Deformations
i. Nutritional origin
Deformations of the maxilla due to deficiencies in Vitamin B5, biotin and folic acid (Gallinaceous birds) or to ingestion of photosensitizationing seeds (Ammi, Cynopterus).
ii. Infectious origin
Cells can be infected by bacteria, virus (Polyomavirus, PBFD), mycoses (Candida spp.), mites (Knemidokoptes), helminthes (Oxyspirura in Cranes).
b. Lateral deviation: scissor beak
The causes are not well known: calcium deficiency, wrong incubation temperature, genetic predisposition, trauma, virus, mycobacteria. In young birds, pressing several times a day on the beak can be effective. In older birds, cutting the gnatotheca on the side opposite to the deviation creates a gliding guide that incites the maxilla to keep its normal position. When the beak is calcified, an apparatus is required.
c. Mandibular Prognathism
In the young bird, placing the maxilla in the right position after every feeding gives a good correction. In older birds, resin prosthesis or more complex systems are used. This system consists in a steel spit through the frontal sinus and elastic straps in cacatoes.
d. Deformations by lateral mandible compression
They are observed in aras and are due to wrong feeding.
5. Beak traumas
a. Maxilla luxation
It is due to traumas in juvenile parrots. The rhinotheca looks displaced dorsally. It is put into the right place under anesthesia.
b. Beak fractures
They are numerous in Cacatuas (mutilation of their female) or in other psittacines (traumas). The treatment aims to:
i. Stop haemorrhage
ii. Put the bones and rhamphotheca onto a same line
iii. Solidarize it with metallic ligatures or broches
iv. Around it, use a prosthesis in resin or in cement glass ionomere
v. Treat with anti infectious.
vi. The fractures are more frequent on maxillas than in mandibles. The post-operatory remaining problems are possible: malocclusion, lateral deviations.
THE CERE DISORDERS
The cere is the naked skin situated at the base of the maxilla. It sometimes is an element of sexual dimorphism (Melopsittacus undulatus: blue in the male and brown in the female).
1. Crust and (or) hypertrophy lesions. The origin is infectious in most cases.
a. Beak mite (Knemidokoptes pilae): Melopsittacus undulatus
b. Poxvirus: pox in canary
c. Trichomonosis: columbiformes et Nymphicus hollandicus
d. Mycobacteriosis: (Mycobacterium avium, M. intracellulaire) in Passeriformes and psittacines.
e. Infections to Candida
f. Vitamin B deficiency
2. Colour change
a. Testicular tumours in the male Melopsittacus undulatus
b. Brown hypertrophy of the cere in the old female Melopsittacus undulatus quantity of carotenoids in the diet (raptors)
3. Deformations
a. Abscess: psittacines
b. Rhinoliths: psittacines