Courtesy of Website “Wing-N-Wave Labradors”

Disorders affecting male fertility are categorized into two groups: those resulting from genetic disorders and those resulting from acquired disorders.

Genetic Disorders - Cryptorchidism.

Cryptorchidism is a condition in which the testes fail to descend into the scrotum (unilateral cryptorchidism/monorchidism describes the condition in which only one testis descends). Cryptorchidism may occur in conjunction with other defects in sexual development or occur as an isolated condition. Isolated cryptorchidism is considered the most common reproductive disorder in dogs, affecting between 1%-15% of dogs. Of these affected dogs, 75% demonstrate unilateral cryptorchidism.

Cause: Cryptorchidism is inherited as a sex-limited autosomal recessive trait.

Symptoms: In the normal canine male, during fetal development, the testes are located in the vicinity of the kidneys and then migrate across the abdominal cavity and eventually descend into the scrotum. The rate of migration can be variable from individual to individual, however, on the average, the testes are completely descended within 10 to 14 days following birth. In only a minority of dogs does descent occur as late as 6 months, and this variation is considered suspect of a developmental abnormality.

Diagnosis: Palpation of the scrotum provides evidence of the presence or absence of two testes. Absence of one or both testes in the scrotum by 8 weeks of age warrants a diagnosis of cryptorchidism. Once cryptorchidism is diagnosed, ultrasonogram is frequently employed to locate the undescended testes or testis within the abdominal cavity or tissues adjacent to the scrotum.

Treatment: Because of the genetic basis of this disorder and its counter-productive ramifications on reproductive soundness in future generations, treatment for cryptorchidism other than surgical sterilization (orchidectomy) is considered controversial from an ethical standpoint. Despite this, however, in one study hormonal treatment using human chorionic gonadotropin administered 4 times over a two-week period was reported to induce testes descent in 21 out of 25 dogs. Treatment was most successful when administered to puppies under the age of 16 weeks.

Prognosis: The specialized physiology of the scrotum is vital for ensuring normal spermatogenesis (sperm production) occurring in the testes. Therefore, normal spermatogenesis fails to occur in bilateral cryptorchids (in which both testes fail to descend), and as a result these dogs are sterile. Normal spermatogenesis, however, will occur in unilateral cryptorchids (in which one testis descends) in the descended testis. Cryptorchid testes have a 6- to 13-fold greater risk for developing a Sertoli cell tumor (testicular cancer) compared to normal testes. Additionally, they run a higher risk of testicular torsion. In light of these observations, bilateral castration(orchidectomy) is recommended even in instances of unilateral cryptorchidism.

Courtesy of Website “Wing-N-Wave Labradors”