The =thickness= of the skin of the horse varies from 1 to 5 mm. in
different regions, and is greatest at the attachment of the mane and the
ventral surface of the tail.
The =glands= are numerous and are larger than those of the other
domesticated animals. The sebaceous glands are specially developed on
the lips, the prepuce, mammary glands, perineum, and labia of the vulva.
The sweat glands are yellow or brown in color. They occur in almost all
parts of the skin, but are largest and most numerous on the outer wing
of the nostril, the flank, mammary glands, and free part of the penis.
In addition to the ordinary and tactile =hairs= certain regions present
coarse hairs of great length. The mane (Juba) springs from the dorsal
border of the neck and the adjacent part of the withers; its anterior
part, which covers the forehead to a variable extent, is termed the
foretop (Cirrus capitis). The tail, with the exception of its ventral
surface, bears very large and long hairs (Cirrus caudæ). The tuft of
long hairs on the flexion surface of the fetlock (Cirrus pedis) gave
rise to the popular name of this region.
The development of these special hairs varies widely, and is in
general much greater in the draft breeds than in others. In Shire and
Clydesdale horses, for instance, the hair on the volar aspect of the
metacarpus and metatarsus and fetlock is often so long and abundant as
to account for the term “feather,” which is commonly applied to it by
horsemen.