"Your dog has an enlarged prostate." Hearing that from your veterinarian seems odd, right? After all, isn't this a problem that only affects older human men?
While you may have never given this hidden gland a second's thought, an enlarged prostate can take a toll on your dog's health just as it does with human men. Benign prostatic hyperplasia in dogs, often referred to as BPH in dogs, is the most commonly occurring condition to affect a dog's prostate.
Though you may not notice any signs of it, an enlarged prostate occurs in nearly all intact (unneutered) male dogs by the time they turn 6, according to a study published by the Veterinary Clinics of North America: Small Animal Practice.
Cause of Benign Prostatic Hyperplasia
The normal dog prostate has two lobes, one on each side of the urethra, with a small indentation between the lobes. The function of the prostate, making fluid that's secreted into the urethra during the ejaculation of semen, is the same for dogs and humans. This action provides nourishment to the sperm and enhances sperm motility so that it's optimized for fertilization.
A commonly encountered problem is the abnormal growth of the prostate, which can cause unpleasant urinary side effects. The risk for BPH in dogs increases with age and is most common in intact male dogs.
The culprit of this gland's unregulated growth is the major male sex hormone often linked with aggression and dominance: testosterone. Testosterone causes certain types of cells in the prostate to grow in number (a condition referred to as hyperplasia) and to enlarge in size (hypertrophy). Over time, this effect causes the prostate to become enlarged.

Signs of BPH in Dogs
Some dogs with BPH don't show any clinical signs. Others may strain to defecate if their prostate is severely enlarged and presses on their colon. The prostatic enlargement may obstruct the dog's urethra, which can lead to straining during urination.
Flat ribbon-like stools are a suggestive sign of benign prostatic hyperplasia in dogs. Bloody ejaculate or bloody penile discharge after mating are also indicative of the condition, says the American Kennel Club.
Diagnosing Enlarged Prostates in Dogs
Though it does require more diagnostics to confirm the cause, an enlarged prostate in dogs is most commonly found during a rectal exam. An X-ray can also be used to diagnose an enlarged prostate.
An abdominal ultrasound may be recommended, as it can confirm that the internal architecture of the prostate is preserved, even when the gland is enlarged. Urinalysis and urine culture may be performed to rule out a urinary tract infection.
Rarely, a biopsy is needed to distinguish benign prostatic hyperplasia in dogs from other causes of prostatic disease, such as an infection or cancer.