Testicular Health in Stud Dogs: What Every Stud Owner Should Know

The testicles are your stud dog's most important reproductive organs — and the ones most commonly overlooked until something goes wrong

Most stud dog owners focus on semen quality, timing, and booking appointments — but the underlying physical health of the testicles themselves is what makes everything else possible. Testicular health conditions are common in intact male dogs, some are life-threatening, and most are identifiable with regular hands-on examination. Here is what every stud owner needs to know.

Normal Testicular Anatomy

A normal dog has two testicles, both descended into the scrotum. Each testicle should be:

• Smooth in texture on the surface
• Firm but not hard — like a hard-boiled egg without the shell
• Symmetrical in size to the other testicle (minor variation is normal; significant asymmetry is not)
• Free of lumps, bumps, or soft spots
• Freely movable within the scrotal sac

Learn what your stud's testicles feel like when he is healthy. Monthly examination — gently rolling each testicle between your fingers and comparing size and texture — allows you to detect changes early.

Cryptorchidism: One or Both Testicles Undescended

What it is: Cryptorchidism occurs when one or both testicles fail to descend from the abdomen into the scrotum by the time the puppy is 6-8 weeks old (though some veterinarians give until 6 months before diagnosing cryptorchidism definitively).

Unilateral cryptorchidism (one testicle retained) is the most common presentation. The dog may appear normal with one visible testicle; the retained testicle is inside the abdomen or inguinal canal.

Bilateral cryptorchidism (both testicles retained) renders the dog infertile because abdominal temperature (too warm for sperm production) prevents normal spermatogenesis.

The cancer risk: Retained testicles are 10-13 times more likely to develop testicular cancer (particularly Sertoli cell tumors and seminomas) than normally descended testicles. The risk increases with age.

Heritable nature: Cryptorchidism is heritable. Dogs with one or both retained testicles should not be used as studs — they will pass the predisposition to offspring. Most reputable breed registries and kennel clubs disqualify cryptorchid dogs from being shown.

Orchitis: Testicular Inflammation

What it is: Orchitis is inflammation of one or both testicles. It may be caused by:

• Brucella canis — The most serious cause of orchitis in dogs. Brucellosis causes severe testicular inflammation, often leading to testicular atrophy and infertility. See the brucellosis guide for full detail.
• Other bacterial infections — E. coli, Staphylococcus, and other bacteria can cause orchitis after ascending infection from the urinary tract or prostate
• Trauma — Bite wounds, kicks, or other physical injury to the scrotal area

Signs of orchitis:

• One or both testicles hot, swollen, and painful to touch
• The dog licking the scrotum excessively
• Scrotal redness or skin changes
• Reluctance to move normally (pain with walking)
• Fever in severe cases

Treatment: Veterinary treatment is required immediately. Bacterial orchitis is treated with antibiotics. Severe cases may require surgical removal of the affected testicle (hemiorchiectomy). Untreated orchitis can result in permanent fertility damage and systemic infection.

Brucellosis orchitis is a medical emergency — a brucellosis-positive dog must be immediately removed from all breeding activity and managed according to your veterinarian's protocol.

Testicular Tumors

Testicular cancer is one of the most common tumors in intact male dogs. Three types are seen:

Sertoli Cell Tumor

The most clinically significant testicular tumor. Sertoli cells are the cells that support sperm production. Sertoli cell tumors can produce estrogen, causing feminization syndrome: bilateral symmetrical hair loss, gynecomastia (enlarged mammary tissue), atrophy of the other testicle, and attraction of other male dogs. Retained testicles have the highest rate of Sertoli cell tumors.

Seminoma

A tumor of the sperm-producing cells. Usually benign and slow-growing, but can metastasize in a small percentage of cases.

Interstitial (Leydig) Cell Tumor

A tumor of the testosterone-producing cells. Usually benign, very slow-growing, and often an incidental finding. Most are not clinically significant.

Signs of testicular tumor:

• A palpable lump, hard nodule, or irregular texture in one testicle
• Asymmetry between the two testicles (one significantly larger)
• Signs of feminization (in Sertoli cell tumors)
• Changes in semen quality or fertility

What to do: Any palpable testicular mass should be evaluated by a veterinarian promptly. Ultrasound can characterize the mass; surgical removal (orchiectomy) is the treatment. Most testicular tumors caught early are curable.

Monthly self-examination is the most important tool for early detection.

Prostate Health and Its Effect on Stud Dogs

While not a testicular condition, the prostate is intimately linked to stud dog fertility and should be part of any reproductive health discussion.

Benign Prostatic Hyperplasia (BPH)

The prostate naturally enlarges in intact male dogs as they age, driven by testosterone exposure. This is not cancer — it is a predictable, physiological change that affects nearly all intact males over age 5.

Signs of BPH:

• Straining to defecate (enlarged prostate compresses the rectum)
• Ribbon-like stools
• Bloody or straw-colored urethral discharge unrelated to urination
• Reluctance to breed or painful ejaculation in severe cases

Treatment: BPH in breeding studs is typically managed with Osaterone acetate (a hormonal medication) or Finasteride, which reduce prostate size without permanently eliminating fertility. Castration is curative but ends the stud career.

Annual prostate palpation by a veterinarian from age 5 onward is recommended for all breeding studs.

When to Retire a Stud for Reproductive Health Reasons

Consider retiring a stud when:

• Testicular tumor is diagnosed — even if treated, ongoing fertility may be compromised
• Brucellosis is confirmed — retirement and management per veterinary protocol is required
• Semen analysis shows consistently declining quality that does not recover
• Prostate disease is causing pain or difficulty breeding

Retiring a stud is not a failure — it is a responsible recognition that the dog's best breeding years have passed. Many retired studs go on to live comfortable, happy lives as companions, and neutering at retirement eliminates future testicular and prostate health risks.

Summary

Monthly testicular examination, annual semen evaluation, and brucellosis testing before every breeding are the cornerstones of stud dog reproductive health management. Know what your stud's testicles feel like normally, so you can detect changes early. Cryptorchid dogs should not be bred. Orchitis requires immediate veterinary attention. Testicular tumors caught early are almost always treatable. And prostate health becomes increasingly important as the stud ages. The stud owners who pay attention to these details are the ones with the longest, most productive careers for their dogs.