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CRYPTORCHIDISM

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) may actually be 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 must 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 United States.

Examining the Pups

A tube called the vaginal process runs from the parietal peritoneum (the inner lining of the abdomen) to the scrotum which it 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 puppies under eight weeks of age, the cremaster muscle also may function to keep the testicles in the tubes but still outside the vaginal ring, instead of allowing them to descend all the way to the scrotum. This could well be Nature's way of protecting them during siblings' roughhousing. 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.

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 your two hands or in the bend of your arm and let his bottom half hang, you should be able to feel the them, especially if two fingers are run down the prepuce, one on each side of the penile sheath, pushing the tiny gonads toward the scrotum. In some pups, they 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 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 not necessarily due to the APL. Two other reasons could be given: 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 Germany for a short while, unilateral cryptorchids were eligible for showing and breeding, as the fault seemed to have no effect on utility or beauty in the GSD and other working breeds. By 1930, the SV prohibited not only showing but registration as well. For a long time, one could still show unilateral cryptorchids in many countries... I remember it was allowed in my eartly years as a handler in Canada. By 1956 the AKC applied the disqualification to all breeds. Even today some feel that cryptorchidism is an imported or German bloodline problem, forgetting that most working breeds derived from Germany, and not knowing that the SV, and later other breed clubs, really led the way in prohibiting the fault.

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 crypt-orchidism. Bilateral crypt-orchidism may also be genetically slightly different, since both 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, and 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 some 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 perhaps half a litter is female, the average would only be 12½ percent and with such breedings that produce one-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 their siring both unilateral and bilateral cryptorchids.

According to one researcher, it is the right testicle which is most often retained, being the more cranial (more toward the head) of the two in the early embryonic stage. In Angora goats, it is also the right testicle that is commonly retained, though this is not hard evidence that all species have the same genetic cause for the same effect. Similarly, the right ovary of females and the right kidney in both sexes are further forward than the left organs. In the normal male, the left testicle in the scrotum is usually carried slightly higher and behind the right one. (Not always, so don't write me correction letters on that!) 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.

As mentioned, unilateral cryptorchidism often seems as if it were a simple, recessive, one-gene Mendelian trait, though it possibly 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.

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 cord and other structures in the genital system but other traits as well?

I believe 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.

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, where registration is denied cryptorchids and sanctions are made against their parents, over half of the "VA" (top show) GSDs in a 20-year period sired cryptorchids and hence were carriers. In England, the prevalence is higher (for a long time such dogs were not penalized in the show ring).

Effects on the Dog

It is common for retained testicles to give a dog a sour or miserable personality, and the condition also seems to be associated with a high 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).

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.