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Cryptorchidism |
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© by Fred Lanting |
The most common congenital
anomaly of the scrotum and testicles is the apparent absence of one or both
gonads. I use the word "apparent" because the missing testicle(s)
usually are actually present inside the body cavity of the dog. The Greek kryptos means hidden, secret, or covered, and the
Greek orchi- is a combining form
referring to the testicles. The condition is therefore called cryptorchidism and the dog so afflicted is called a cryptorchid. If one testicle is retained, he is a
unilateral (one-sided) cryptorchid and if both, a
bilateral cryptorchid. A word commonly applied to the
former is monorchid but this is a misnomer, as
monorchidism would mean the presence of only one
testicle anywhere in the body, not just in the scrotum. True monorchids are quite rare, as are anorchids
(males with no testicles), and either condition can be verified only be
extensive surgery.
A dog whose testicles have been
removed is commonly but inaccurately referred to as having been
"neutered", but more accurately he is called a castrate. Such a dog
generally has no (or greatly reduced) response to sexual stimuli, while a
sterile bilateral cryptorchid may have normal sex
urge, and a unilateral cryptorchid is usually both
virile and fertile.
Show Rules
The AKC and almost every other
club requires every dog competing in shows to have two
normal testicles in the scrotum. Judges are supposed to examine the scrotum,
and usually a quick pass of the hand between the thighs will let them know if
one is too spongy, hard, or abnormally small, indicating the possibility of
disease or chicanery. In some countries testicle abnormalities are more
severely penalized and in some places less is demanded of the judge than is the
case in the
Examining the
Pups
A tube called the vaginal
process runs from the parietal peritoneum (the inner lining of the abdomen) to
the scrotum which that lining encloses. Inside this
tube are the spermatic cord, artery, vein, nerves, vas deferens, and the cremaster muscle. It is the function of this muscle to pull
the testicle closer to the body in cold environs, and to allow the scrotum to
hang lower in warmer conditions. In the abdominal wall, there is a ring-like
passageway through which the testicles move sometime soon after birth; in cryptorchidism, one or both stay inside that wall while the
opening gets too small for later passage. It may be a genetic defect in the
length of the spermatic cord that is the most important reason. In puppies
under eight weeks of age, the cremaster muscle also
may function to keep the testicles in the tubes but still outside that “vaginal
ring” of the abdominal wall, instead of allowing them to descend all the way to
the scrotum. Perhaps a defect in this muscle is responsible for the fairly
common "elevator testicle" in certain family lines: in this
phenomenon, one goes up, comes down, and goes back up again. Usually this is
outgrown rather early, but I knew of one pup that still exhibited this
condition at the age of five months. In
some breeds, such as Toy Fox Terriers, it is not uncommon to find testicles absent
from any scrotum, but present just outside the vaginal ring, very hard to
palpate.
People who can't find the
testicles in young puppies may be holding the little shoelace-tuggers in the wrong position. The testicles should descend
before birth, but are so small and mobile they may be nearly impossible to find
on a wriggling pup that doesn't want to be constrained. But if you cradle the
pup's upper body in the bend of your arm and let his bottom half hang, you
should be able to feel the them, especially if thumb and index finger are run
down the prepuce, one on each side of the penile sheath, pushing the tiny
gonads toward the scrotum. You can use the middle finger to feel for them while
the other two fingers slide downward and push in that direction. It’s a little
like squeezing toothpaste from one end toward the opening of the tube. In some
pups, they simply will have to be pushed into the scrotum this way in order to
be noticed. Some folks panic when only one can be found; they run to the
veterinarian for some magic shot of hormone to make the other appear. While the
synthetic hormone APL (anterior pituitary-like) has had some success in humans,
its efficacy is probably zero in dogs. First, it definitely is of no benefit
once the testicle has grown too large to squeeze through the vaginal ring, and
therefore the need would have to be discovered at or soon after the time of
birth, which is all but impossible even if one has the most sensitive fingers
in the world. Then, if the other testicle does appear in the scrotum, it's
probably coincidental and not due to the APL: the testicle was going to drop
anyway, or it was in the inguinal canal outside of the abdominal wall and held
up by a tight cremaster which loosened as the pup
aged. (There is no evidence that APL works as a relaxant on the cremaster.) Even if APL were a successful way to induce
testicles to drop, the pup's genetic makeup would remain the same and he would
pass the defect along to many of his offspring. As a responsible breeder you
would find a pet (non-breeding) home for him.
Inheritance
In
The most recent studies on the
subject of missing or hidden testicles indicate that there can be several
genetic causes. Retractile testicles, a feature of the dog with an overactive
or short cremaster, may be due to a genetic
determinant quite different from that which causes classic unilateral cryptorchidism, as I have indicated and observed from
personal observation. Bilateral cryptorchidism may
also be genetically slightly different, since both testes are usually found in
almost the same ovarian position as they are in the early fetal
life of normal males. It seems that this phenomenon may be caused by two or
more genes. Such may be the case in unilateral cases too, although there is
reliable data to suggest the possibility of a simple Mendelian
recessive in the case of
classic unilateral cryptorchidism. If
two normal-phenotype dogs actually carry the recessive, on an average one might
expect 25 percent of the litter to show the condition. But since about half of
each litter is female, the average would only be 12˝ percent. With such breedings that produce one-apparent-testicle dogs not being
often repeated, it's difficult to find meaningful statistics. I have observed
that when unilateral cryptorchids are bred, there is
a high probability of them siring both unilateral and bilateral cryptorchids.
According to one researcher, it
is the right testicle that is most often retained, being the more cranial (more
toward the head) of the two in the early embryonic stage. The retained testicle
in unilaterally affected dogs is usually found near the bladder or at the
entrance to the inguinal canal on the inside of the abdominal wall, as if it
had been arrested on its way to join its mate. In
As mentioned, unilateral cryptorchidism often seems as if it were a simple,
recessive, one-gene Mendelian trait, though possibly
it is not. If the problem of unilateral cryptorchidism
is indeed simply recessive, the occurrence of bilateral cryptorchids
might have to be explained by the action of other, modifying genes, and many
geneticists today do not find that idea appealing. But for the purpose of
explanation, let's use it as an example. If the pup inherits one gene for the
trait from one parent and one normal allele from the other parent, he will not
show the disorder but will be a carrier. If the normal gene is represented by
the capital letter C, and the defective gene is identified by the lowercase c,
his genetic constitution on that chromosome is Cc. On the other hand, if a dog
is a cryptorchid, his genetic constitution at that
locus on that chromosome is cc (two defective genes). If this dog is bred to a
bitch that also inherited two such genes, (she is also a cc), all of their
offspring will either be cryptorchids like the sire
or homozygous carriers like their dam. It is possible that a testicle found in
the scrotum of some very young pups from such a union may later retract and be
trapped inside the peritoneum. In some breeds this happens fairly frequently,
and some believe it is caused by the same set of genes that cause more typical cryptorchidism. The difference between unilateral and
bilateral cryptorchids may also be due to the
presence of certain modifier genes”.
In addition, some breeds with brachiocephalic skulls have a much greater than 25 percent
incidence of orchidism when supposed normals (actually carriers) are bred. Knowing what we do
about such breeds and their pituitary defects, would it not be reasonable to
say that maybe many breeds and species have in their population a very slight
hereditary pituitary defect that acts not only on the development of the
spermatic cord and other structures in the genital system, but other traits as
well? Breeds that have been selected by fancy to be what Noah would have
considered grotesque include the (“English”) Bulldog, said to be a compilation
of all the disqualifying and serious faults of most other breeds. The reason
for these “defects” stems from genetic defect s in the hypophysis
or pituitary gland, the “master gland” deep in the base of the brain. It is the
master of the other endocrine glands including those others with functions
related to growth of various and all parts of the body. In the GSD, for
example, we have a particular defect that results in pituitary dwarfism (see
pictures in “The Total German Shepherd Dog”) and such dogs, while nearly
perfect in proportions, often have serious thyroid gland problems with
resultant loss of hair that makes some of them look like Chinese Crested
hairless dogs. Remember what I said about the interconnection between endocrine
glands. Other defects produce the Bullmastiff face, the Cocker or Corgi dwarf
legs, etc.
I believe it is safe to say that
cryptorchidism is genetic, that it is in some way
recessive, and that there is some sort of connection between bilateral cryptorchids and unilateral ones. Perhaps there is also a
connection between the pituitary and floating testicles. At any rate, the
unilateral condition at least is so widespread in many families and breeds that
an all-out effort to combat it would take our minds and efforts away from more
serious disorders, which would consequently increase. It’s just a minor thing
we have to put up with. Simply remove the affected ones from the gene pool, and
shift your preference away from breeding any (including females) that come from
litters in which the defect occurred.
Since cryptorchidism
is sex-limited (only affected males, not carrier females, show it) it is likely
to persist at about the same prevalence in the breed for a long, long time. In
Germany and many other countries, where registration is denied cryptorchids and sanctions are made against their parents,
more than half of the "VA" (top show) GSDs
in a 20-year period sired cryptorchids and hence were
carriers. In
Effects on the
Dog
It is common for retained
testicles to give a dog a grouchy, sour, or miserable personality, and the
condition also seems to be associated with a higher than normal percentage of
testicular cancers or tumors on the retained gonad.
For both reasons, many veterinarians recommend castration even if the testicles
are undescended. A third possible effect is cryptorchidism's reported connection with early fetal death of females in litters with affected males, with
these females either resorbed or, in some cases,
mummified. The gene or genes may be semi-lethal ones which are only sometimes
expressed in the death of the female embryo, and which sometimes cause the
surviving bitch pups to be sterile if they are homozygous (cc). Mummy puppies
can cause great difficulties in abortions of later pregnancies, lack of or
decreased contractions, and stillborn pups in subsequent litters. So if there is
a connection with cryptorchidism, that’s another
reason to avoid families in which it appears.
Dogs that are castrated early in
life do not have the same development of bulk and other attributes of
masculinity that intact males do. This is primarily because the primary source
of testosterone and other “male hormones” has been cut off — literally. Remember that all the endocrine glands (those
producing hormones) and “connected” in a way analogous to a network of
businessmen, electricity generator grids, etc.
When one is affected, almost all the others “feel” it. Many hormones are
required to make endocrine glands in another part of the body function
optimally. Sometimes the hormones normally generated by a specialist gland can
be produced in small quantities by other glands when the principal supplier is
lost. Still, for normal development of
the various organs, all the endocrine glands should be present and
healthy.
Partial castration (removal of
the retained testis) or complete castration produces very few other noticeable
effects if the dog is allowed to mature before the operation. By then, the
testosterone and other hormones have had their intended effect and the dog has
developed into a large enough, masculine enough dog suitable for anything an
intact dog would be used for. Perhaps
those wishing to have an impressive dog that could take down a schutzhund helper might want to postpone such an operation
until the dog is older and fully developed.
On the other hand, many (perhaps most) dogs never have any adverse
reactions to leaving the undescended testicle in. Some (few?) dogs with no
surgical correction become grouchy-grumpy, and there is a slightly increased
risk of testicular cancer but I really don't think it's great. The vets who
operate make some money as they do on ANY surgery, but there are many cases
when they cannot even FIND the undescended one. So the question of whether to open him up and
look for it is a personal one, based on many factors.
Ethics
Veterinarians are sometimes
asked to surgically correct cryptorchidism by moving
the testicle(s) down into the scrotum, but this is an extremely difficult and
delicate operation with very little chance of success because of the length of
the spermatic cord, the effect on attached tissues and blood vessels, and other
technical reasons. An easier alternative is to implant a synthetic testicle -
glass, silicone, or whatever - and veterinarians are quite often asked to do
this. However, nine times out of ten the owner's motives are questionable at
best. Usually he wants the surgery so his dog can compete in shows, or so he
can fool owners of bitches into paying for stud service from what is supposedly
a normal dog. Best to keep cryptorchidism in perspective, and be above-board in your
data and honest in your statements and dealings. Educate your puppy buyers if
you are a breeder, and they will acknowledge that such recessive traits will
always be in the breed. They will also learn that if you do the selective breeding
I recommended, your kennel’s incidence will be lower
than the average in the general population.
