By 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 to deal with is a complete abdominal retention, when the testicle is fully retained in the abdomen, and is mobile within the abdominal cavity. Typically this testicle will be small and flabby, and extremely unlikely to produce sperm (although there has been one case reported), sperm would be infertile, and the testical is not externally palpable.
Incomplete abdominal retention is only marginally easier to deal with. 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 laying down under anesthesia.
Permanent inguinal retention is where the testicle has descended through the deep inguinal ring but trapped within the inguinal canal. It is difficult or impossible to palpate, and may be palpable with the horse laying down under anesthesia. Caution should be used as it’s possible to mistake the results of this palpation as 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 second testicle sometimes being retained abdominally. An animal with this condition is sometimes known as a ‘high flanker’.
Temporary inguinal retention is the condition that holds the most hope for a horse’s owner. The retained testicle may be palpable within the inguinal canal with the horse standing, and certainly palpable with an anesthetized horse laying down. 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 its own volition by the age of three, although cases of it not descending until the horse is six have been recorded. In this case the testicle can sometimes be aided in its descent by treating the animal with hCG (human chorionic gonadotropin), which will artificially stimulate the natural testosterone production, thereby encouraging descent... To read the complete article you need to be a subscriber
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