Cryptorchidism --
During growth of
a male fetus, the testicles develop in the abdominal cavity, pass
through an opening in the body wall called the inguinal canal, and
descend into the scrotum. Normally both testicles have
descended into the scrotum at or shortly after birth.
Occasionally descent is not complete until 5 to 6 months of age.
In some
individuals, however, one or both testicles fail to descend into the
scrotum. Dogs with both testicles undescended are usually
sterile, while those with only one testicle undescended are fertile.
This is a polygenic (multiple genes involved) inherited defect and
when trying to breed out the condition, unilateral crytorchid dogs
should not be allow to mate.
Dogs with
undescended testicles should be castrated because the condition is
thought to be hereditary, the dogs are not eligible for show, and
the incidence of testicular tumors in testicles that remain in the
abdomen is much greater than the incidence in descended testicles.
