ABOUT CLEFT PALATE I N HORSES
“No primary palate defects
[those that involve the
nostrils and lips] were iden-
tified in this study. All of
the defects involved either
the hard and/or soft palate.”
The most common defects,
she adds, affect the rear
two-thirds of the soft palate,
meaning they are not out-
wardly visible and are found
only during an endoscopic
exam of the pharynx.
Even without visible signs
of the defect, there are usual-
ly other indications of palate
problems. “Most commonly,
foals with cleft palate will
demonstrate dysphagia [diffi-
culty eating and swallowing]
that results in bilateral na-
sal discharge of milk,” Shaw
says. “Older animals with
cleft palates may have persis-
tent nasal discharge, cough,
or have a history of pneumo-
nia or respiratory infections.”
Eleven percent of the
study horses underwent sur-
gical repair of their cleft pal-
ate, 4 percent received only
supportive care (such as
treating resulting respira-
tory infections) and 32 per-
cent had no treatment. Of the
28 cases of cleft palate, 46
percent survived to be dis-
charged from the hospital.
About 50 percent of the
horses with cleft palate were
euthanatized, a rate that
might reflect concern over
the potential complications of
treatment. “Cleft palates can
result in aspiration pneumo-
nia,” says Shaw, “which can
be life-threatening, so surgi-
cal correction is often recom-
mended. However, surgical
complications such as
dehiscence [reopening] of
the suture line, osteomyelitis
[infection] of the mandible,
and chronic dysphagia are
reported to occur in up to
90 percent of attempted
repairs. Yet, in this study,
most cases that were eu-
thanatized were not treated
surgically. The likelihood
of complications and the
cost of surgical and medical
therapy may have influenced
owners’ decisions.”
On a more positive note,
the researchers identified a
few adult horses who were
managing quite well despite
a cleft palate. “None of these
horses had involvement of
the hard palate, and it is pos-
sible that they had more mi-
nor defects of the soft palate
for which they were able to
compensate,” says Shaw. “A
number of these horses had
careers as riding horses or
racehorses without any ap-
parent deleterious effects of
their cleft palate.”
Canadian Veterinary Journal,