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Cryptorchidism (Undescended Testicle) in Dogs

Occurrence: common
Location of illness: Abdomen/pelvis

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

CryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. is a developmental disorder in male dogs where one or both testicles fail to descend into the scrotum. Instead, they remain in the abdominalThe term "abdominal" refers to anything that concerns the belly or the abdomen. It is an adjectival expression used to describe the location, symptoms, or conditions that occur in the abdominal area. cavity or inguinal canal.

The most important facts at a glance

Cryptorchidism, also known as undescended testicle, affects approximately 1-3% of male puppies. Normally, the testicles descend into the scrotum by the eighth week of life, but in cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer., this process remains incomplete. Genetic factors play a significant role, especially in breeds such as German Shepherds, Boxers, and Chihuahuas, suggesting a hereditary predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases.. Hormonal and environmental influences during pregnancy can also affect testicular descent. Symptoms are usually a missing testicle in the scrotum or a swelling in the groin area, which can cause infertility. DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made by physical examination, occasionally supported by ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow.. The main treatment is surgical removal of the undescended testicle to reduce the risk of testicular tumors. In unilateral cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer., the healthy testicle is often also removed to prevent genetic transmission. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. is good if treated early. For preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring., affected dogs should not be used for breeding. Research focuses on genetic causes and environmental influences to develop better diagnostic and treatment methods.

Causes

Undescended testicle is a relatively common anomalyAn anomaly is a deviation from what is considered normal or expected. In medicine, it often refers to unusual physical or genetic characteristics that may be present at birth or develop later. in dogs, occurring in approximately 1-3% of male puppies. The normal descent of the testicles into the scrotum occurs in the first weeks of the puppy’s life, typically by the eighth week. In cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer., this process remains incomplete.

The causes of cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. are not fully understood, but genetic factors are believed to play a significant role. The condition is more common in certain breeds, including German Shepherds, Boxers, Chihuahuas, and Poodles. This suggests that hereditary factors significantly contribute to the predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases..

In addition to genetic factors, hormonal and environmental influences during the mother dog’s pregnancy could also play a role. For example, disturbances in testosterone levels could affect the normal development and descent of the testicles.

Symptoms

Very common symptoms:

Common symptoms:

The most noticeable symptom of cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. is the absence of one or both testicles in the scrotum, which is detected during a physical examination. In an incomplete examination, the condition may go unnoticed.

Another symptom may be an asymmetrical or irregular size of the scrotum if only one testicle is affected. In bilateral cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer., the testicles appear completely hidden in the abdominalThe term “abdominal” refers to anything that concerns the belly or the abdomen. It is an adjectival expression used to describe the location, symptoms, or conditions that occur in the abdominal area. cavity, which is more difficult to detect.

Affected dogs may have an increased risk of testicular tumors in adulthood, especially if the testicles remain in the abdominalThe term “abdominal” refers to anything that concerns the belly or the abdomen. It is an adjectival expression used to describe the location, symptoms, or conditions that occur in the abdominal area. cavity. In addition, cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. can lead to behavioral problems such as aggression, which are influenced by the increased testosterone level.

Diagnosis

The diagnosis of cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. is usually made through a thorough physical examination of the dog. The veterinarian palpates the scrotum to determine if one or both testicles are missing. In young animals, the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. can be delayed until the age of six months, as testicular descent may be delayed.

In some cases, an ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. examination may be necessary to determine the exact position of the testicle, especially if it is located in the abdominalThe term "abdominal" refers to anything that concerns the belly or the abdomen. It is an adjectival expression used to describe the location, symptoms, or conditions that occur in the abdominal area. cavity. This helps to detect and treat potential complications such as testicular tumors early.

Genetic tests are not currently widely used, but could play a role in the future in identifying carriers of the disease to avoid breeding affected animals.

Therapy

The recommended treatment for cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. is surgical removal of the undescended testicle, a procedure called cryptorchidectomy. This significantly reduces the risk of testicular tumors and other health complications.

In cases of unilateral cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer., the descended testicle is often also removed to minimize the risk of genetic transmission of the anomaly. Castration also prevents unwanted behavioral problems associated with elevated testosterone levels.

In some cases, especially in valuable breeding animals, hormonal treatment may be considered to promote testicular descent. However, this method is controversial and not always successful.

Prognosis and follow-up care

The prognosis for dogs with cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. is generally good, especially if the condition is detected and treated early. Surgical removal of the affected testicles is a routine procedure with low risks and a quick recovery time.

If left untreated, there is an increased risk of developing testicular tumors, which can worsen the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop.. Testicular tumors in cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. are often more aggressive and difficult to treat, which is why early removal of the affected tissue is important.

After treatment, most dogs can lead a normal, healthy life. Castration can also help reduce behavioral problems that may be associated with the condition.

Prevention

Since cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. has a genetic component, the best preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. is not to use affected dogs for breeding. This prevents the transmission of the genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. to future generations.

Regular veterinary examinations in the first months of a puppy’s life are important to detect cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. early. This allows for timely treatment and prevents possible complications.

A healthy diet and care of the pregnant dog can also help minimize the risk of developmental disorders in the offspring, although this alone cannot completely prevent cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer..

Outlook on current research

Undescended testicle, also known as cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer., is one of the most common congenitalCongenital means "present from birth" and refers to characteristics or conditions that are already present at birth. This can include genetic disorders, developmental anomalies, or infections transmitted by the mother. reproductive disorders in dogs. This condition has garnered significant attention in the scientific community because it can not only affect the fertilityFertility refers to the ability to conceive and bear offspring. In women, it refers to the ability to initiate and carry a pregnancy; in men, it refers to the ability to produce fertile sperm. of affected animals but also increase their risk for certain health problems, such as testicular cancer and testicular torsion. Research is currently focused on various aspects of this condition, including genetic predispositions, environmental influences, and better diagnostic and therapeutic approaches.

A significant research focus is on identifying the genetic markers responsible for cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer.. Scientists have discovered that it is a polygenetic disorder, meaning that multipleMultiple means manifold or repeated and is used to describe conditions or events that occur in multiple instances or at different locations. In veterinary medicine, this may indicate multiple lesions, tumors, or other pathological changes. genes are involved in its development. Modern techniques such as genome sequencing and association studies are being used to identify specific gene variants that are associated with an increased risk of undescended testicle. These discoveries could lead to genetic tests in the future that breeders can use to better assess the risk of cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. in their breeding lines.

Another area of research is investigating the role of environmental influences in the development of cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer.. Studies have shown that certain chemical substances, known as endocrine disruptors, can disrupt the hormonal balance during embryonic development, which can lead to an increased risk of cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer.. These substances can be found in pesticidesPesticides are chemical or biological substances used to control pests, including insects, weeds, and fungi. In dogs and cats, exposure to certain pesticides can be harmful to health and lead to signs of poisoning., plastic products, and other industrial chemicals. The research aims to better understand these compounds and develop strategies to minimize exposureExposure refers to the Contact with or subjection to certain substances, environmental factors, or pathogens. In veterinary medicine, this can include Contact with toxins, allergens, or infectious agents that can cause health problems in dogs and cats. during critical developmental phases.

Regarding the treatment of cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer., current studies are focusing on developing less invasiveInvasive describes medical procedures or pathogens that enter the body or penetrate tissue. In medicine, invasive procedures can range from minimally invasive techniques to open surgery. and more effective surgical techniques. While castration of the affected dog is the most common treatment method, some scientists are exploring the possibility of moving the testicles into their correct position to preserve fertilityFertility refers to the ability to conceive and bear offspring. In women, it refers to the ability to initiate and carry a pregnancy; in men, it refers to the ability to produce fertile sperm.. However, these surgical techniques are still in the experimental phase and require further investigation to ensure their safety and effectiveness.

In summary, research in the field of cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. in dogs is making promising progress. The combination of genetic studies and the investigation of environmental influences could lead to better preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. and treatment of this condition in the future. This would not only benefit the health of the affected dogs but could also improve breeding practices and expand the general understanding of reproductive biology in mammals.

Frequently asked questions (FAQs)

What is cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. in dogs? CryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. is a condition in which one or both testicles of a male dog do not descend into the scrotum. This can be detected at birth or shortly thereafter and is one of the most common reproductive disorders in male dogs.
How common is cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. in dogs? CryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. occurs in about 1-3% of male dogs, with some breeds being more susceptible than others. Toy and small dog breeds are particularly affected.
What causes cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer.? This condition is caused by a combination of genetic and possibly environmental factors. Several genes can influence the risk, and exposureExposure refers to the Contact with or subjection to certain substances, environmental factors, or pathogens. In veterinary medicine, this can include Contact with toxins, allergens, or infectious agents that can cause health problems in dogs and cats. to certain chemicals during the mother’s pregnancy may also play a role.
What risks are associated with cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer.? Dogs with cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. have an increased risk of testicular cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas. and testicular torsion. The condition can also lead to hormonal disorders that can affect the dog’s behavior.
How is cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. diagnosed? The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is usually made by a physical examination of the dog by a veterinarian, who determines whether the testicles are present in the scrotum. In some cases, additional imaging procedures such as ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. may be necessary to determine the position of the testicles.
What are the treatment options for cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer.? The most common treatment is surgical removal of the undescended testicles to reduce the risk of complications such as cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas.. This procedure is called castration. In some cases, an attempt may be made to move the testicles into the scrotum, but this is rare and often unsuccessful.
Can dogs with cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. be bred? It is strongly advised against breeding dogs with cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer., as the condition has a genetic component and can be passed on to offspring. Breeding such dogs could increase the risk that the offspring will also be affected.
Are there ways to prevent cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer.? Since cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. has a genetic component, preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. is limited. However, careful breeding selectionSelection refers to the process of natural or artificial selection of specific individuals for reproduction, based on desired genetic traits. In breeding, this is applied to promote specific characteristics in dogs and cats. can help reduce the risk. This includes not using dogs with known cases of cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. in breeding.
At what age should a dog with cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. be neutered? It is recommended that dogs with cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. be neutered at the age of six to twelve months, before the risk of testicular cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas. increases significantly. However, the exact timing may vary and should be discussed with a veterinarian.
Does cryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. affect a dog’s behavior? CryptorchidismCryptorchidism is an anomaly in which one or both testicles do not descend into the scrotum. This can occur unilaterally or bilaterally and has potential effects on fertility and increases the risk of testicular cancer. itself does not usually affect a dog’s behavior. However, hormonal changes associated with the condition can sometimes lead to behavioral problems that can be mitigated by castration.