In horses, the most commonly diagnosed oral congenital deformity is parrot mouth, in which the maxilla is relatively longer than the mandible. In equids and cattle, many anomalies of dental development may result from exposure to teratogenic toxins. However, underlying genetic factors should always be considered.
Dental irregularities accompany systemic fluorosis in both cattle and sheep. In the milder forms of fluorosis, only the dentition may be involved. In extreme fluorosis (eg, 40 ppm in the diet for several years), other skeletal abnormalities may be seen (phalanx fracture). (see also Fluoride Poisoning.)
Supernumerary teeth (polyodontia) are seen occasionally. In both horses and cattle, double rows of incisor teeth or extra cheek teeth may be seen. Treatment is determined on a case-by-case basis and may require extraction of the extra teeth.
see also Congenital and Inherited Anomalies of the Digestive System: Congenital and Inherited Anomalies of the Teeth.
Last full review/revision March 2012 by Jack Easley, DVM, MS, DABVP (Equine); Gregg A. DuPont, DVM, Fellow AVD, DAVDC