Testicular Hypoplasia and Degeneration
The normal testicle is smooth, oval, and has a regular outline. Both testicles should be of similar size and feel rather firm. The size of the testicle is related to its sperm-producing capacity. Accordingly, small testicles in a sexually mature dog can produce a smaller number of sperm.
Testicular hypoplasia is a developmental disorder in which one or both testicles fail to reach normal size at sexual maturity. The small size and flabby consistency of these testicles is caused by poor development of sperm-producing tissue. An ejaculate will show either no sperm or a low number of sperm with numerous abnormal forms. There is no effective treatment.
Testicular degeneration is an acquired disease that can result in either permanent or temporarily sterility. Unlike testicular hypoplasia, the testicles were normal before they became small. A common cause of reversible testicular degeneration is high fever. Effective sperm production requires that the scrotal temperature be at least 2 - 3 degrees below the core body temperature. Fever raises both body and scrotal temperatures. Diseases associated with fever that can cause temporary testicular degeneration include canine distemper, parvovirus, and leptospirosis. Hypothyroidism is also a major cause of infertility in mature male dogs. If any of these conditions persist, permanent infertility can occur.
Immune-mediated orchitis occurs following testicular biopsy and trauma in which sperm escape and enter the blood stream. The escaped sperm cause the body to produce antisperm antibodies. The antibodies destroy the sperm in the dog's own testicles.
In all of the conditions described here, the testicles become small and flabby like those of a dog with testicular hypoplasia.
There are also diseases that destroy the testicles - these are testicular trauma and acute bilateral orchitis. In testicles damaged in this way, the sperm-producing tissue is replaced by fibrous connective tissue. The testicles become small and hard. Sterility is irreversible in these cases.
Cause depends on the particular condition.
Diagnosis can be made by your veterinarian.
Testicular degeneration is treated by correcting the underlying disease and allowing time for spontaneous recovery. Sexual rest is essential. Semen examinations are used to monitor the return of spermatogenesis. It takes 50 - 60 days for regenerating sperm to reach the ejaculate, so any improvement in sperm quality will not be seen for at least 2 months.
There is no effective treatment for Testicular hypoplasia.
Please contact your veterinarian for more information regarding this condition.
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