Monthly Newsletter Volume 4, No 5 May 2005

Cryptorchidism in the Colt
Jos Mottershead

Prior to a colt foal being born his testicles are "stored" within the abdominal cavity. Shortly before birth they descend through the inguinal ring, and into the scrotum. Sometimes for a variety of reasons one or both (more commonly one) do not descend as they should. The vaginal rings close during the first two weeks of the foal's life, and this will prevent a testicle that has not fully descended from the abdomen at that point from subsequent descent.

There are several types of cryptorchidism, or testicular retention.

The hardest type to deal with is a complete abdominal retention . With this, the testicle is fully retained in the abdomen, and is mobile within the abdominal cavity. Typically this testicle will be small and flabby. It is extremely unlikely that it will produce sperm, although there has been one case reported. The sperm in such a case would not be fertile. The testicle is not externally palpable.

Incomplete abdominal retention is only marginally easier to deal with, in that the retained testicle is not mobile within the abdominal cavity, but is usually located close to the deep inguinal ring, with portions of the testicles attached tissue passed through the vaginal ring, where they can sometimes be palpated externally with the horse standing, and often when the horse is laid down under anesthesia.

Permanent inguinal retention is where the testicle has descended through the deep inguinal ring, but is trapped within the inguinal canal. It is difficult or impossible to palpate, and may be palpable upon the horse being laid down under anesthesia. Caution should be used in that it is possible to mistake the results of this palpation for those of an incomplete abdominal retention. In both instances the tail of the epididymis within a vaginal process may be felt. Either testicle can be retained, with the other testicle also sometimes being retained abdominally. An animal with this condition is sometimes known as "high flankers".

Temporary inguinal retention is the condition that holds the most hope for the horse's owner. The retained testicle may be palpable within the inguinal canal with the horse standing, but will certainly be palpable with the horse laid down under anesthesia. The right testicle is the one most commonly affected (in more than three-quarters of cases). With this type of retention the testicle will usually descend of it's own volition by the time the colt is three years of age, although cases of it not descending until the horse is six have been recorded. In this type of retention, the testicle can sometimes be aided in it's descent by treating the animal with hCG (human chorionic gonadotropin), which will artificially stimulate the natural testosterone production, thereby encouraging descent.

Except as otherwise noted, and in some cases of temporary inguinal retention sperm production is nil, and any sperm produced will be infertile. This is as a result of the lack of temperature control afforded by the ability of the raising and lowering of the testicle to achieve an even body temperature. Occasionally sperm may be produced in the temporary inguinally retained testicle if it is located close to the scrotum.

The cryptorchid may not be capable of producing viable sperm, but testosterone production will not be affected. This means that once the animal reaches puberty (usually between 12 and 18 months), he will start to act in a stallion-like manner, which can be dangerous for those not familiar with it, and inconvenient for those that are. Additionally, at this stage the stallion will be capable of breeding a mare, although he may not be fertile depending upon whether one or both testes are retained. In the event that only one testicle is retained the second testicle will probably be fully functioning, and therefore any mare bred may become pregnant. As cryptorchidism is possibly a heritable trait (this is a hotly debated topic, with "proof" being shown both for and against the theory), this situation is not desirable. From an ethical point of view, perpetuation of such a trait should not be considered. Increased castration costs will result for male offspring that inherit the condition, and lower total numbers of sperm produced will be inclined to make any affected animal less fertile. Replication is therefore damaging to a Breed generally, and to individual owners financially, if not physically as a result of unexpected stallion-like behaviors.

Castration costs are increased depending upon the degree of retention, and therefore what level of surgery is required. Obviously full abdominal surgery is required for the completely abdominally retained testicle, as that surgery would be more extensive than for a temporary inguinally retained testicle should that be performed. Full anesthesia is recommended in all instances. Pricing will vary from surgery to surgery and surgeon to surgeon, but costs in excess of US $1,000 would not be unlikely for the more complicated surgeries.

© 2000 Jos Mottershead. www.equine-reproduction.com

Thanks to Jos Mottershead for use of this excellent article regarding cryptorchidism.
More articles regarding equine reproduction can be found on the very informative web site: http://www .equine-reproduction.com .

A Few Quick Facts Regarding Foals and Foaling:

• A newborn foal's legs are already 90% of the length they will be when full grown.
• A foal is able to stand just one hour after birth.
• A foal can walk, trot, and run just two hours after birth!
• The first milk the mare makes is called colostrum. This is a rich milk and it is very important for the foal, because it helps protect it against disease.
• Most foals will start to nurse less than two hours after being born.
• A female foal is called a filly.
• A male foal is called a colt.
• More foals are born between April 15- May 15 than any other time.
• Mares usually foal at night.
• Mares don't like to be watched when they foal. If someone is watching, they might stop foaling and wait till the the person goes away.
• A mare may give birth in as little as 15 minutes, but no longer than an hour. If she is still straining after an hour has passed, something is seriously wrong.
• If you have to help pull a foal out, NEVER pull up! Always pull down, toward the horse's feet

Foals may be insured for full mortality at 24 hours of age.  A completed application and a veterinary certificate preformed when foal is a minimum of 24 hours including the foals IgG level are required. Call us for more information.

Jarvis Insurance is asking for the use of very good photographs for our new updated web site, which is in the process of being developed right now,  as well as our monthly newsletter.  Video footage is also needed for use on the new web site. Submissions may be sent via e-mail or regular mail to Kim Jarvis at the address below in Solon, Ohio.

Newsletter written by W. Anthony Pontrello
Produced by www.tonyontheweb.com