Cleft Palate or Cleft Lip (Harelip) Complex This is due to a
disturbance of the processes that form the jaw and face during
embryonic development. Cleft of the lower lip is rare and
usually occurs on the midline. Clefts of the upper lip, usually
at the junction of the premaxilla and maxilla, may be unilateral
or bilateral, complete or incomplete, and often are associated
with clefts of the alveolar process and palate. The defect may
also involve the palate alone, affecting the hard or soft
components of the palate, or both. Developmental anomalies
affecting other organ systems are seen in ~8% of dogs and cats
with cleft palate or lips. Similarly, in large animals, cleft
palate or lip is commonly seen with other defects, such as
arthrogryposis, which is inherited in a simple autosomal
recessive manner in Charolais cattle. In Texel sheep, a syndrome
of bilateral cleavage of the lip with accompanying defects of
the maxilla has been reported to have an autosomal recessive
mode of inheritance. In small animals, in