Reproductive Emergencies in the Stallion

 Although uncommon, reproductive emergencies will occur in the breeding stallion and when they do, prompt attention and action must be instituted. Trauma to the external genitalia is always a possibility under natural mating situations whether the stallion is used in a hand mating situation or field breeding. Some mares are presented to the stallion when not in true standing estrus or even if in estrus they can react violently to being mounted by the stallion In addition, stallions can also be injured when semen is collected by the use of an artificial vagina in an inappropriate manor when mounting a phantom or jump mare.

The majority of injuries or accidents I see are the result of direct trauma (kick from a mare) or to a lesser extent from a mare's tail hairs stretched across the vulva lips. Occasionally, trauma to the penis can occur to bending of the penis during semen collection with an artificial vagina or on the phantom itself. When these types of injuries occur, disruption in the breeding season occurs, and we should try to resolve the insult as quickly as possible.

Inflammation of the penis (balanitis) is probably the most common disease of the penis. If the prepuce is included, then balanoposthitis is more descriptive. Swelling and redness are the most obvious signs.

Equine herpes 3 is a viral cause of balanitis (Pox, coital exanthema). The disease is characterized by small blister-like vesicles forming on the shaft of the penis and occasionally on the prepuce. Serum is exuded and in three to seven days small crusts will form on the lesions. When these crusts fall off, small ulcer-like lesions remain, which soon heal. Since the virus is spread by coitus (intercourse), sexual rest is the treatment of choice. In addition, a mild antibiotic ointment might be applied to the lesions to prevent or minimize secondary bacterial infections. This disease is highly contagious and the stallion should be out of service until healing is complete. This usually takes one to four weeks.

Trauma to the penis and/or prepuce from kicks, improper fitting stallion rings, rubber bands form artificial vaginas, and artificial vaginas themselves are the most common causes of balanoposthitis seen in my practice. Rarely are there open wounds when this type of trauma results.

Heat, swelling, and pain are the most obvious signs associated with this type of injury. Reducing swelling with cold water therapy should be instituted immediately. Begin hosing four to six times per day for 15-20 minutes with cold water. If there are any wounds, antibiotics systemically and topically can be used. In addition, anti-inflammatories should also be used. Results of treatment are evaluated daily. Massage might also be appropriate to decrease swelling. After three to four days, warm water can be used for hydrotherapy to stimulate circulation.

If the penis has prolapsed, a suspensory apparatus might have to be fashioned to prevent further swelling and/or trauma. I have rarely had to use this, and the apparatus is not without its own problems. If the penis can be returned to the prepuce, this should be done and a purse string suture in placed if necessary in the preputial oufice to prevent further swelling.

Penile hematomas are usually a result of kicks or other forms of trauma. The hemorrhage generally is caused by injury to the vessels of the venous plexus on the dorsum of the penis. Rapid swelling occurs at various places along the shaft of the penis.

Initially, compression by use of a bandage can be indicated. Cold packs or cold water therapy, diuretics, and anti-inflammatories are also used. Once the initial insult is under control, the formation of fibrous tissue should be minimized. Daily penile massage is recommended to help avoid penile deviation. Surgical exploration of the hematoma is warranted in some situations.

Obviously, prevention of trauma to the penis is extremely important. In my opinion, stallion rings have no place in the management of stallion reproductive performance and should not be used. The mare's tail should be bandaged prior to mating and the mares twitched. In addition, a front leg of the mare can be held or strapped up during the time that the stallion is mounting and let down once he is on the mare. Most importantly, mare behavior and previous mating history should be evaluated. In addition, in artificial mating situations, bending of the penis during semen collection with an artificial vagina and direct trauma with the phantom should be avoided at all costs.

Hemospermia is another condition that needs to be addressed as a semi-emergency at least. Overt hemorrhage into the ejaculate can severely affect pregnancy rates. Infertility appears to be caused by the presence of the red blood cells themselves.

The causes of Hemospermia are very variable and include:

  • Bacterial urethritis;
  • Lacerations of the shaft of the penis;
  • Cutaneous habronemiasis;
  • Urethral lacerations;
  • Viral urethritis; and
  • Infection or inflammation of the accessory sex glands. (i.e. seminal vesiculitis).

External examination of the penis and urethral process for signs of trauma, summer sores, or infections should be the first step when presented with hemospermia. A flexible fiber optic endoscope can be used to examine the urethra, and seminal vesicles. Ultrasound of the accessory sex glands per rectum can also be done. Treatment is based on the underlying cause and sexual rest is indicated in all cases.

Orchitis is an inflammation of the testes. Swelling, pain, and heat are the principal signs. One or both testes might be affected. Trauma is the most common cause, but infection and testicular torsion should also be considered. History, clinical appearance, palpation, and ultrasound are useful for a diagnosis. Since the heat and swelling can be a serious threat to seminal quality, treatment must be instituted quickly. Cold water hydrotherapy, anti-inflammatories, diuretics and antibiotics, if indicated, should be started immediately.

Testicular torsion is diagnosed by the addition of colic signs and palpation. Some of these can be relieved by rotation of the testicle. Surgery might be necessary in some cases.

Hydroceles are caused by a transudate in the vaginal cavity. The scrotum is enlarged and fluctuating fluid can be palpated. The condition is rarely painful and is easily diagnosed with an ultrasound examination. Free fluid is seen around and ventral to the testes within the scrotum. The effect of the fluid is to insulate the testes and interfere with thermoregulation of the testes and sperm production. Anti-inflammatories and diuretics have helped some cases of hydrocele when treatment was begun immediately. Long standing cases seem more refractory (resistant) to treatment. Trauma, high ambient temperature, and congenial abnormalities have been suggested as causes.

Penile paralysis and priapism are two other rather rare conditions of the penis of the stallion. Penile paralysis involves the retractor penis muscle. It occurs after the use of the phenothiazine-derived tranquilizers and in debilitated horses.

Priapism is a persistent erection or semi-erection without sexual arousal and is initially associated with penile paralysis. Protracted engorgement of the corpus cavernosum penis with blood is associated with this condition.

Medical treatment involves penile massage, slings, anti-inflammatories, diuretics, and replacement of the penis into the preputial cavity. Various surgeries to create shunts, phallopexis, acupuncture, and various other medical treatments have been tried with variable success rates. The prognosis becomes worse the longer the condition exists. Penile amputation is a treatment of last resort.

About the Author

John Steiner, DVM

John Steiner, DVM, is associated with the Hagyard-Davidson-McGee veterinary firm near Lexington, Ky., and specializes in reproductive problems.

Stay on top of the most recent Horse Health news with FREE weekly newsletters from Learn More

Free Newsletters

Sign up for the latest in:

From our partners