What are Orchitis?
There are several reasons that a stallion may develop swollen testes, including illness, trauma, or parasites. Swollen testes, medically referred to as orchitis, may affect any age of intact male horse and is not unique to any particular breed. It is crucial to have a horse with orchitis examined by a veterinary professional as long-term swelling of the testes may lead to abscess and untreated infections may become systemic and spread to other parts of the body. Stallions who have developed orchitis should not breed until the swelling and the underlying cause are both addressed.
Orchitis is the inflammation of the testes. This particularly uncomfortable condition may be caused by trauma, illness, and infestation, and can affect any horse that still has intact testes.
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Symptoms of Orchitis in Horses
There are several signs that you may see with orchitis beyond just the noticeable increase in size and redness of the groin area. Additional symptoms that may occur with swollen testicles may include:
- Abdominal pain
- Decrease in semen quality and motility
- Hard mass in scrotum
- Hopping gait
- Increase in abnormal sperm
- Loss of appetite
- Loss of libido
- Pain in groin
- Rapid heart rate
- Testicular area is hotter than normal
Additional symptoms may arise that are related to the underlying cause of the swollen testes.
This is the inflammation of the epididymis, which sits on top of the testes in equines, and serves as the storage center where the sperm are kept during their maturation period. Orchitis and Epididymitis may occur simultaneously, but they can also happen independently. In some cases, horses that are castrated may have all or part of the epididymis left in place and may end up with epididymitis even without the full testicle.
This condition, an accumulation of fluid in the scrotum, is rare in the stallion. Treatment is usually the removal of the testicle on the side affected by the hydrocele
Varicocele refers to a condition in which the spermatic vein is elongated and curled back on itself. This can raise the scrotal temperature of the horse, sometimes causing a drop in sperm production. It can also allow clots to form which become inflammatory masses that are often very similar to orchitis.
Causes of Orchitis in Horses
- Autoimmune orchitis - Autoimmune orchitis occurs spontaneously in horses, as well as in dogs and in mink
- Illness - Infection by streptococcus zooepidemicus is the most common bacterial or viral disease to cause orchitis, but bacteria and viruses such as Salmonella, influenza, and equine infectious anemia can also affect the testes; these infections usually start in the urethra and migrate to the testes
- Infestation - Infestation by parasites like Strongylus species can also irritate and inflame the testes if they migrate through that area
- Spermatic cord torsion - When the spermatic cord gets twisted it can cut off the flow of blood to and from the testicle, this can lead to painful swelling and death of the testicle can occur in as little as a few hours
- Trauma - Physical damage, such as a hard blow, may cause bruising and swelling of these glands as well
Diagnosis of Orchitis in Horses
When your veterinarian examines your stallion, they will most likely start with a full physical evaluation, with particular attention paid to the male glands and the structures that support them. A rectal examination is also likely to be completed as this technique allows the veterinarian better access to palpate the abdominal organs. Although the testes cannot be accessed this way, the condition of organs such as the kidney and spleen may provide valuable information about underlying conditions.
An ultrasound is usually the imaging method of choice when dealing with soft structures such as the testicles, and proper visualization is essential when attempting to diagnose the underlying cause of the inflammation. Standard blood tests, like a complete blood count and biochemical profile, will help to determine if any bacterial or viral infections are present in the blood, and an antibody titer may help to determine exactly which particular agent is responsible.
Treatment of Orchitis in Horses
Initial treatment of the testicles should be focused on reducing both the swelling and the heat associated with it. This disorder can quickly become a threat to the quality of the stallion’s semen, not to mention their overall condition. Cold water hydrotherapy or ice packs are often utilized to reduce the heat in the area, and the swollen testicle should be supported using a scrotal sling, and in most cases, the patient will benefit from the proper anti-inflammatory and pain relief medications. Further treatment is dependent on the underlying cause.
If the spermatic cord is twisted and it has only been a short time, it may be able to be untwisted by the horse’s doctor, however, if more than a few hours have elapsed since the damage, then the testicle will most likely require surgical removal. Infections and infestations will be prescribed the appropriate antibacterial, antifungal, or possibly anti-viral medications and these should be continued as long as your veterinarian recommends as early cessation of these medications can encourage a reoccurrence of the disease.
Recovery of Orchitis in Horses
The prognosis for stallions that experience orchitis is dependent on the severity of the underlying condition. Many cases, such as mild infection or simple bruising, may heal and recover completely, allowing the stallion to continue breeding at their previous levels. Situations in which the testes are in an inhospitable environment for longer periods, as are created when infections involving fever or disorders that inhibit blood flow in the scrotal area, both the motility and overall condition of future sperm production may be permanently impaired. In severe cases, one or both testicles will need to be removed completely by surgical intervention to prevent further disability.