Prostate disease is extremely common in intact male dogs over age 5, most often presenting as benign prostatic hyperplasia (BPH). Signs include straining to defecate, blood in urine or semen, and a stilted gait. Castration is curative for most BPH cases; more serious conditions like prostatitis and prostatic cancer require prompt treatment.
Last reviewed: June 2026
What Is Prostate Disease in Dogs?
The canine prostate is a gland surrounding the urethra at the base of the bladder. Unlike men, where the prostate wraps around the urethra and causes urinary obstruction when enlarged, the canine prostate sits more caudally and tends to cause rectal and colonic compression when enlarged — leading to ribbon-like stools and straining to defecate rather than urinary blockage. As described in Nelson & Couto's Small Animal Internal Medicine, benign prostatic hyperplasia (BPH) is the most common prostate condition in intact male dogs, affecting over 80% of intact dogs by age 6 and virtually all by age 9. The prostate responds directly to testosterone; castration reduces BPH-related prostate size by 50–70% within 3 weeks and up to 80–90% within 3 months. The AAHA Canine Life Stage Guidelines, 2019 include discussion of reproductive health and neutering decisions as part of senior dog care planning.
Types of Prostate Disease in Dogs
| Type | Signalment | Key Signs |
|---|---|---|
| Benign prostatic hyperplasia (BPH) | Intact males >5 years | Ribbon-like stools, blood in urine/semen |
| Prostatitis (bacterial) | Intact or recently neutered | Fever, lethargy, painful prostate, pus in urine |
| Prostatic abscess | Intact males | Septic signs, rectal compression, abdominal pain |
| Paraprostatic cysts | Any age | Abdominal mass, urinary changes |
| Prostatic carcinoma | Often neutered older males | Weight loss, hind-leg weakness, urinary signs |
Signs of Prostate Disease in Dogs
- Straining to defecate — tenesmus from rectal compression by the enlarged prostate
- Ribbon-shaped or flattened stools — narrowed by the enlarged gland
- Blood in urine — typically intermittent, bright red drops at end of urination or from the urethra independent of urination
- Blood in semen — visible during ejaculation or bloody preputial discharge
- Stilted or stiff hindlimb gait — pelvic discomfort causes the dog to take short, careful steps
- Difficulty urinating — less common than straining to defecate; urethral compression is possible
- Fever, lethargy, pain — indicates prostatitis or abscess, which are more serious
- Abdominal or perineal swelling — paraprostatic cysts or large abscesses may be palpable
Diagnosis
Rectal palpation allows the vet to feel the size, symmetry, and texture of the prostate. Normal prostate is bilobed, smooth, non-painful, and roughly walnut-sized. BPH produces symmetric, smooth, non-painful enlargement; prostatitis produces pain; carcinoma causes asymmetric, irregular nodules.
Supporting diagnostics: urinalysis and urine culture ($50–100); abdominal radiographs ($150–300); abdominal ultrasound ($250–450) to assess architecture and guide aspirate; ultrasound-guided fine-needle aspirate for cytology ($200–400); prostatic wash ($150–250); biopsy for definitive diagnosis if cancer suspected ($300–600).
Treatment
- BPH: castration is curative and preferred. For breeding dogs or owners declining surgery: finasteride (anti-androgen) reduces prostate size by 40–50% within 2 months; deslorelin (GnRH agonist implant) is an effective medical castration alternative; cost $60–150/month for medications, or $300–800 for implant
- Prostatitis: long-term antibiotics (minimum 4–6 weeks) selected based on culture; fluoroquinolones and trimethoprim-sulfa have good prostatic penetration; cost $60–120 for drug course; hospitalization if septic
- Prostatic abscess: surgical drainage and often castration; hospitalization and surgery $1,500–4,000
- Prostatic carcinoma: poor prognosis overall; piroxicam (NSAID) has palliative evidence; toceranib (Palladia) in some cases; consult veterinary oncologist
When to See a Vet
Call your vet today if:
- Your intact male dog is straining to defecate or producing ribbon-like stools
- You notice blood in your dog's urine or from the prepuce not associated with urination
- Your intact male dog over age 5 hasn't had a prostate check at a recent annual exam
Go to the ER immediately if:
- Your dog has a fever, is severely lethargic, or appears to be in significant pain
- Your dog cannot urinate or is straining to urinate without producing any urine
- Abdominal distension develops rapidly
What's going on with your pet?
Describe symptoms or snap a photo. Voyage tells you urgency, home care, and whether you need a vet.
First, tell us about your pet
Breed and age make a real difference in how Voyage interprets symptoms.
Describe the symptoms
Love it? See everything Voyage can do
Frequently Asked Questions
Is prostate disease common in neutered dogs? BPH (the most common prostate condition) virtually never occurs in neutered dogs because it requires testosterone. However, prostatic carcinoma is actually more common in neutered dogs than intact ones — representing about 6% of all prostate disease but carrying a very poor prognosis. Carcinoma signs in neutered dogs are the same: bloody discharge, straining, hindlimb stiffness.
How is prostate disease diagnosed in dogs? Rectal palpation, urinalysis with culture, and abdominal ultrasound are the core diagnostics. Ultrasound with fine-needle aspirate gives the most specific information about BPH vs. infection vs. cancer. Prostatic biopsy is reserved for cases where aspirate is non-diagnostic and cancer is suspected.
What does prostate disease treatment cost in dogs? Castration for BPH: $300–800. Medical BPH management (finasteride): $60–100/month. Prostatitis antibiotics: $60–120 per course. Abscess surgery and hospitalization: $1,500–4,000. Cancer palliative care: $100–400/month ongoing. Diagnostic workup: $400–1,200 for ultrasound, aspirate, and culture.
How quickly does the prostate shrink after castration? Prostate size decreases approximately 50–70% within the first 3 weeks post-castration. By 3 months, the gland is 80–90% reduced. Straining to defecate and bloody urine signs typically resolve within 1–4 weeks of castration in straightforward BPH cases.
Can prostate disease in dogs be prevented? BPH is almost completely preventable by neutering before age 5. Castration is the most effective preventive — intact dogs allowed to age past 5 face near-certain BPH. Prostatic carcinoma is not preventable (and neutering may slightly increase the risk, though the disease remains uncommon overall).
Still Not Sure if Your Dog Needs a Vet?
When you're not sure if this is wait-and-see or call-tonight, Voyage AI Vet triages in under 2 minutes. Describe what you're seeing in chat, share photos of any discharge and describe your dog's defecation patterns, or hop on a live video call if you want a second pair of eyes. Every answer comes with citations to the actual veterinary literature it's pulling from — so you see exactly where the guidance comes from, not just a chatbot's word.