Cleft palate is commonly seen by veterinarians in dogs, cats and other species. Defects (clefts) in the hard palate that forms the roof of the mouth, or the soft palate which lies caudally and separates the oropharynx from the nasopharynx may be congenital or acquired. The cleft can involve the soft palate alone, the hard palate alone or both.
Congenital cleft palate is an abnormality which is thought to occur during fusion of the maxillary process with the medial nasal process, when the mesodermal fusion develops across the fused epithelial surfaces. If the epithelial barrier does not degenerate or if the mesodermal connective tissue is deficient cleft palate results. Acquired clefts are due to trauma - usually road traffic accidents or falls from a height.
There are several possible causes for congenital cleft palate:
An hereditary basis for the disease is suspected for congenital clefts but the mechanism has not yet been determined. Any such genetic trait is thought to be multifactorial recessive, polygenic and dominant with partial penetration.
Vitamin A is an essential nutrient for normal growth and defects in bone growth are seen with insufficient as well as excessive dietary intake. Vitamin A has a controlling influence over both the osteoblasts and osteoclasts in epithelial cartilage and so there is a rational explanation as to why excessive vitamin A intake might result in cleft palate.
In addition, commercially prepared complete pet foods contain more than sufficient available vitamin A yet breeders and owners frequently supplement their pet's ration with vitamin supplements. High vitamin A content is also a feature of many natural food sources including liver and fish oils. Cod liver oil is a very popular nutritional supplement with pet owners and it contains 18000mg per 100ml (4000 IU per gram). Some vitamin injections contain as much as 500,000 IU of vitamin A per ml.
Administration of cortisone during pregnancy can lead to the development of cleft palate in the fetus
Administration of the cytotoxic drug hydroxyurea (hydroxycarbamide) is reported to cause cleft palate.
Acquired cleft palate is common following falls from a height, and less commonly following road traffic accidents.
The following breeds of dog have been reported to have cleft palates : mixed and small terrier breeds, Beagle, Bernese Mountain Dog, Boston Terrier, Bullmastiff, Bull Terrier, Chihuahua, Cocker Spaniel, Collie, Dachshund, English Bulldog, German Shepherd Dog, Golden Retriever, Miniature Schnauzer, Norwegian Elkhound, Pekingese, Shih Tzu, Staffordshire Bull Terrier, Toy Poodle Wire-haired Fox Terrier,
There is a visible split in the roof of the mouth or the soft palate. This results in food material (particularly fluids) passing into the nasal cavity and the following signs : - Fluids eg milk pass down the nose during feeding
- Sneezing
- Coughing/gagging
- Snuffling
- Rhinitis
- Pneumonia (due aspiration of foods)
- Poor weight gain
- Stunted growth
- Inability to feed properly
http://www.provet.co.uk/health/diseases/cleftpalate.htm
