Unlike the female, few medical conditions affecting the male reproductive system are life-threatening. This is why, although early neutering increases the life expectancy of females it does not do so with males. The most common problems cause discharge from the prepuce and changes in the size of the testicles. Both are more common in dogs than in cats.
Preputial Discharge - Sheath And Penis Infection - Balanoposthitis
A male dog normally produces a cream-yellow coloured lubricant in the sheath (smegma). In young dogs this can be quite productive, dripping out when the dog is resting. Preputial drip can be aesthetically unpleasant but is not a medical problem. Excessive drip, especially foul-smelling drip and increased redness accompanied by increased licking suggests injury or infection to the sheath or penis. Causes include:
- Bacterial infection
- Herpesvirus infection
- Foreign bodies such as grass seeds
- Physical injury
- Failure of lubricant secretion
Bacterial infection can be cultured and antibiotic sensitivity determined. Viral infection is much more difficult to diagnose. Failure to respond to antibiotic treatment raises the possibility of herpesvirus infection.
Penis Stuck Out Of The Sheath - Paraphimosis
Long hair on the tip of the prepuce can cause the skin to roll inwards when a dog has an erection. During an erection the bulbourethral gland on the penis can swell so much it is too wide to retract into the sheath. If an erection is prolonged lubricant can reduce the difficulty retraction. Affected dogs lick and look uncomfortable. In our experience this is a particular problem in young, oversexed Yorkshire Terriers. Paraphimosis also occasionally is seen in dogs after castration.
Lubricate the penis with water soluble lubricant such as KY Jelly, liquid paraffin or if these are not available, a little vegetable cooking oil. Retract the prepuce further back, or the penis forward, to release trapped hair that has caused the prepuce to roll over on itself. Slide the penis back in its sheath. If this is not possible, keep the penis moistened with any of these lubricants and get our immediate help. In some circumstances surgery is needed to reduce strangling of the penis.
In the fetus, testicles develop inside the abdominal cavity, near the kidneys. As the fetus develops they migrate down, through the inguinal rings into the scrotum. Migration always occurs by birth or a few days after. If neither testicle migrates, and they remain in the abdominal cavity the pet is called a cryptorchid. If only one testicle migrates through an inguinal ring, the pet is a monorchid. It is not unusual for testicles to migrate through the inguinal rings but then dally for a while, between the skin in the groin and the inguinal muscles before continuing their travel down into the scrotum. Undescended or partly descended testicles is an inherited condition in many breeds.
There is a high incidence of cancer in undescended testicles. Abdominal testicles should be surgically removed. Partly descended testicles that have passed through the inguinal ring can be monitored for changes in texture or size and removed if and when necessary. Because this condition is inherited, dogs and cats with partly or completely undescended testicles should not be used for breeding.
A tumour is the most common cause of painless testicle enlargement. Testicular tumours occur in older dogs, usually over seven years old.
Infection or injury from dog bites, frostbite or contact with corrosive chemicals cause painful enlargement. A moist scrotal skin infection causes weeping skin damage that heals into a hard, carapace-like scab, giving the impression of testicle enlargement.
Tumours seldom cause clinical signs, although a female hormone producing tumour causes skin changes including hair loss, increased pigmentation to the skin in the groin and enlargement of teats. Unless they are enormous, tumours are most frequently diagnosed during routine yearly physicals. If a dog has a pain-producing testicular injury or infection (orchitis) he stands and walks with his legs spread.
Tumours are surgically removed and identified by a pathologist. Malignancy is rare. Penetrating injuries are treated with pain killers and antibiotics. Cold packs are sometimes used. Skin infection is cleaned with skin antiseptic such as chlorhexidine (Hibiscrub). Dogs are given pain killers and antibiotics. Elizabeth collars are often necessary to prevent protective scab from being licked off.
Prostate Conditions In Dogs
The prostate, which wraps around the urethra as it emerges from the bladder, produces nourishing transport liquid for sperm. The prostate commonly becomes infected when there is either bladder or urethra infection. Aggressive antibiotic treatment is necessary. Most other prostate conditions cause prostate enlargement. Clinical signs are associated with partial or complete obstructions caused by the enlarged prostate.
All prostates increase in size with time. The gland reaches its maximum size usually between six and ten years of age, swelling and pushing upon the floor of the rectum. This causes a flattened bottleneck for stool to pass through. Initial signs of benign hyperplasia include ribbon-like stools or difficulty passing stools. In rare instances hyperplasia can produce small to enormous prostatic cysts.
Prostate infection also causes swelling. There may be signs of constipation but also more frequent urinating and pus or blood in the urine.
Prostate tumours are quite rare. I have seen two in over 30 years, in a Bull Terrier and a Lurcher.
Hyperplasia is diagnosed by rectal digital examination. A dog may be treated with injections that often shrink hyperplasia. Severe hyperplasia is arrested and reduced by castration. Prostatic cysts are confirmed by x-ray or ultrasound. If these are causing problems in the abdomen they are surgically corrected. Infection is identified by bacterial culture and sensitivity and treated accordingly. A prostatic tumour is fast growing and more painful than hyperplasia. Tumours progress rapidly and are not amenable to surgery. Treatment is aimed at eliminating pain for as long as possible.