REPRODUCTIVE EMERGENCIES IN THE STALLION

Transcription

1 EMERGENCY TREATMENT IN THE ADULT HORSE /94 $ REPRODUCTIVE EMERGENCIES IN THE STALLION Nigel R. Perkins, BVSc, MS, and Grant S. Frazer, BVSc, MS A reproductive emergency is considered by the authors to be a condition that is-or may develop into-a life-threatening situation for the stallion, or one that may pose a serious threat to fertility. In the latter case, urgent attention is required to reduce inflammation and to prevent any long-term adverse effects on either spermatogenesis or the animal's ability to satisfactorily complete the copulatory act (erection, intromission, and ejaculation). Although reproductive emergencies usually involve the reproductive tract, they may result from a routine reproductive procedure or occurrence. COMPLICATIONS OF CASTRATION Castration is one of the most commonly performed surgical procedures involving the colt or stallion. Complications, although uncommon, can represent a life-threatening risk to the animal. Unfortunately, they are a common cause of litigations involving veterinarians. Hemorrhage Excessive hemorrhage is the most common life-threatening complication. 16 The usual source of severe hemorrhage is the testicular artery of the spermatic cord. 4 Hemorrhage may occur when emasculators are applied incorrectly, or if excessive tissue is placed within the emasculators From the Department of Veterinary Clinical Sciences, The Ohio State University (GSF), Columbus, Ohio; and the Department of Veterinary Clinical Sciences, Massey University (NRP), Pahnerston North, New Zealand VETERINARY CLINICS OF NORTH AMERICA: EQUINE PRACTICE VOLUME 10 NUMBER 3 DECEMBER

2 672 PERKINS & FRAZER thereby interfering with the ability of the instrument to crush the spermatic artery sufficiently to result in hemostasis. It is critical to use goodquality instruments and that the instruments are correctly applied before crushing. When castrating stallions older than 2 years of age, the clinician should isolate the vascular portion of the spermatic cord and emasculate it separately from the musculofibrous portion. This will ensure adequate crushing of the arterial supply.4 If there is a continuous stream of blood from the spermatic cord, or if bleeding has not stopped within 20 to 30 minutes, then an attempt should be made to re-emasculate or ligate the spermatic cord. The severed end of the cord should be grasped and retraced, then either forceps, emasculators, or a ligature should be applied. 16 This may require additional sedation or even general anesthesia. An alternative approach, and in those cases in which the end of the spermatic cord is inaccessible, the scrotum may be packed with sterile gauze soaked in saline that contains 0.1 % povidone iodine. One end of the gauze is exteriorized through the scrotal incision. The scrotal incision is sutured or closed temporarily with towel clamps. The pack is removed after 24 to 36 hours. If the horse continues to hemorrhage at this time, an attempt should be made to locate and ligate the vessel under general anesthesia. 16 In animals that have undergone considerable blood loss, hemorrhagic shock should be countered by intravenous infusion of high-volume crystalloid solutions and/ or whole blood.4 Eventration Prolapse of intestine through the inguinal canal is the most critical and immediately life-threatening complication of castration.4 Observation of either omentum or intestine protruding from the scrotal incision is an indication for immediate corrective surgery. Eventration usually occurs within 4 hours of castration, but it has been reported to occur up to 6 days later.4 When managing a case of eventration, the prolapsed tissue should be cleansed thoroughly, then attempts should be made to replace it within the abdominal cavity. In tractable animals with small amounts of herniated tissue, an attempt may be made to manipulate prolapsed tissue back into the abdomen via transrectal palpation. This is usually not successful in the majority of cases and is not recommended unless surgery is not an option. The approach recommended by the authors entails immediate cleansing of the prolapsed tissue and then replacing it within the scrotum. The.scrotal incision is closed with sutures or towel clamps while the animal is transported and/or prepared for surgery. A sling may be placed around the inguinal area to provide some support for the scrotum during transportation.4 Surgical sites should be prepared for both a ventral midline, as well as inguinal approach. The procedure is best performed with the anesthetized horse placed in dorsal recumbency. The

3 REPRODUCTIVE EMERGENCIES IN THE STALLION 673 eventrated tissue should be lavaged with copious amounts of sterile saline containing a broad-spectrum antibiotic. An incision is made over the inguinal ring, and the parietal vaginal tunic is dissected free up to the level of the superficial inguinal ring. IS In some cases, the vaginal ring must be enlarged, or a ventral midline celiotomy performed to facilitate return of intestine to the abdomen. 4 Resection and anastomosis may be necessary if intestinal viability is compromised. The vaginal tunic, including the spermatic cord stump, should then be emasculated, ligated, and transected as proximally as possible.is The superficial inguinal ring is then sutured, and a drain is inserted into the scrotal incision to facilitate postoperative scrotal drainage. Alternatively, the inguinal ring may be packed with sterile gauze that is left in place for 2 to 3 days. The animal should be treated with broad-spectrum antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), fluid therapy, and should be placed on restricted feed. Scrotal drains can be removed on the second or third day, and skin sutures can be removed after 10 to 14 days. If marked preputial edema develops, hydrotherapy and a liberal application of ointment to the penis and prepuce may be necessary.. Funiculitis Infection of the spermatic cord generally results from inadequate scrotal drainage. Poor surgical technique, contaminated ligatures, and excessive tissue handling may also result in bacterial contamination of the surgical site. Treatment includes hydrotherapy, antibiotics, and the establishment of ventral drainage for the scrotum. Removal of the infected spermatic cord stump may be indicated. This is especially true in cases in which the cord has been ligated because there is an increased risk of abscessation. 4 Peritonitis Peritonitis is an uncommon complication of castration. It generally develops secondarily to an infection involving the spermatic cord (see Funiculitis). Clinical signs of depression, fever, anorexia, colic, weight loss, constipation, or diarrhea after castration may be suggestive of peritonitis. I6 Because uncomplicated castrations can be accompanied by alterations in the peritoneal fluid, the presence of peritonitis should be diagnosed by considering other factors (i.e., fever, depression, ileus)9 Abdominocentesis, however, is still warranted. The peritoneal fluid should be examined for cytological evidence of degenerate neutrophils and bacteria. Treatment includes broad-spectrum antibiotic therapy, NSAIDs, fluid therapy, and possibly peritoneal lavage.

4 674 PERKINS & FRAZER SCROTAL AND INGUINAL HERNIAS In a scrotal hernia, there is a protrusion of abdominal viscera down through the external inguinal ring and into the scrotum. A hernia is said to be inguinal if the viscera is situated between the vaginal and external inguinal rings. 16 Hernias are further described as being direct if the viscera lies outside the vaginal cavity and indirect if the viscera lies within the vaginal cavity. The majority of both inguinal and scrotal hernias are of the indirect type in horses. The term ruptured scrotal hernia is used to describe an indirect scrotal hernia in which the parietal vaginal tunic has tom releasing viscera to lie partially outside the vaginal tunics. The clinician should examine castration candidates for evidence of a preexisting hernia before proceeding with the surgery. Detection of a hernia would warrant a more complicated approach to the castration. Inguinal and scrotal hernias are most common in male horses at birth or soon after. If a congenital inguinal or scrotal hernia is present in a foal, a distended, soft, fluctuant scrotum will develop soon after birth. Such hernias generally are reduced quite readily by digital manipulation of the scrotal contents. They usually resolve spontaneously during the first 3 to 6 months of life. 16 The authors recommend that affected foals be observed closely, and the herniated viscera be manually replaced 2 to 3 times each day. A retention bandage has been described for more severely affected foals. 16 The foal is anesthetized, placed in dorsal recumbency, and the hernia is reduced completely. Wads of cotton wool are then placed over the external inguinal rings and bandaged in position by a figure eight bandage. This passes between the hind legs and over the dorsum of the pelvis. The bandage may be left in place for up to 1 week. Care should be taken to avoid excessive pressure because this may cause obstruction of either the penile urethra or anus. Colic signs may indicate the presence of intestinal incarceration or a ruptured scrotal hernia. In these cases or when the scrotal hernia is irreducible, the foal should be prepared for surgery. Once again, it is important to prepare the surgical sites for both an inguinal and ventral midline approach in case intestinal resection is required. The patient should be placed in dorsal recumbency and an incision should be made over the inguinal ring. Once the hernia is reduced, the vaginal tunic should be ligated close to the level of the external inguinal ring. Apposition of the edges of the external inguinal ring is also recommended. Bilateral castration and ligation of the vaginal tunic is recommended even if herniation seems to be unilateral. Herniation may also occur in older horses after breeding, exercise, or severe trauma. 16 Standardbreds, Saddlebreds, and Tennessee Walking horses seem to have a higher incidence of inguinal herniation than other breeds. 7 Acquired inguinal or scrotal hernia in stallions invariably produces intestinal obstruction and acute colic. Immediate surgical repair is essential? Clinical signs are typical of intestinal strangulation. A scrotal or inguinal hernia should always be on the differential diagnosis list when an intact male horse exhibits signs of colic. The diagnosis may be

5 REPRODUCTIVE EMERGENCIES IN THE STALLION 675 confirmed based on direct palpation, ultrasonographic examination of the scrotum and contents, and by transrectal palpation of the vaginal ring for evidence of viscera entering the inguinal canal. In some cases, manual reduction by a combination of external and internal palpation may be possible if attempted immediately after occurrence of the hernia. 16 The horse should be sedated and the scrotum and testicle grasped and pulled downward to straighten and tense the vaginal cavity. Prolapsed viscera is then gently milked upwards towards the abdomen. Additional traction may be applied to the viscera by gentle manipulation per rectum. This may require epidural anesthesia and can result in trauma to the rectal mucosa and entrapped viscera. Excessive manipulation must be avoided. Surgical reduction of the hernia and/or repair of the damaged inguinal canal is performed with the anesthetized horse placed in dorsal recumbency. The initial surgical approach for inguinal and scrotal repair is via an incision over the inguinal ring? The vaginal tunic is incised and herniated viscera evaluated for viability. Enlargement of the vaginal ring is frequently necessary to facilitate replacement of intestine within the abdomen. A ventral midline incision may be necessary to provide additional traction to the bowel and, in some cases, to facilitate resection and anastomosis of intestine. Replacement of intestine is then followed by castration, transfixion ligation of the vaginal tunic, and suturing of the external inguinal ring. If unilateral castration is performed, the inguinal skin incision is closed and a second incision is made over the ventral scrotum to facilitate drainage of the area. The scrotum may be packed with sterile gauze soaked in dilute betadine. Breeding stallions may retain an acceptable level of fertility with only one testicle provided that spermatogenesis has not been impaired in the remaining testicle. Although removal of the affected testicle is often recommended as a means of preventing recurrence of the hernia, occasionally an attempt may be made to correct the herniation without removal of the ipsilateral testicle. In such cases, care should be taken to ligate only the cranial portion of the external inguinal ring, leaving approximately 2.5 em of the caudal portion of the ring unsutured to allow passage of the spermatic cord and vas deferens. Complications include secondary herniation and vascular compromise of the testicle? TORSION OF THE SPERMATIC CORD Spermatic cord torsion occurs when the testicle has rotated on its vertical axis. In some stallions, the spermatic cord may develop a transient torsion of up to 180 degrees without any apparent adverse effects. 16 There are cases in which one testicle is fixed in a 180-degree rotated position. Spermatic cord torsion of more than 180 degrees (generally, 360 degrees) may be associated with acute scrotal pain and inflammatory edema. Affected horses show signs of colic and may walk with a stilted

6 676 PERKINS & FRAZER gait. 16 Thus, this condition should also be considered when an intact male horse exhibits signs of colic. Once vascular compromise has produced ischemic necrosis, the acute pain often subsides. However, edema of the scrotal contents distal to the site of the torsion will soon develop. This should alert the clinician as to the true cause of the recent colic episode if the correct diagnosis has not already been made. In acute cases, diagnosis of spermatic cord torsion depends on the presence of severe scrotal pain and resistance to palpation. Locating the position of the ligament of the tail of the epididymis (gubernaculum) may be useful in diagnosing spermatic cord torsion, although in cases of 360-degree torsion, the cauda epididymis will be in its normal position. Scrotal swelling can make palpation difficult, and the authors have found that the use of ultrasonography invariably provides useful diagnostic information. In the presence of swelling, it may be difficult to differentiate inguinal herniation from spermatic cord torsion without transrectal palpation of the internal inguinal rings. The preferred treatment is removal of the compromised testicle, with ligation and transection of the spermatic cord proximal to the site of the torsion. Bilateral castration is recommended if the horse is not intended as a breeding stallion. If surgical correction of the torsion has been performed early enough to preserve testicular blood supply, an orchiopexy may be used to prevent recurrence of the condition. 14 This salvage procedure may be warranted in valuable breeding animals. 16 SCROTAL AND TESTICULAR TRAUMA Direct trauma to the scrotum may occur in breeding accidents (e.g., a mare kicking). Resultant injuries may lead to a permanent reduction in fertility unless prompt and aggressive therapy is instituted. Blunt trauma will produce severe localized inflammation with edema of the scrotum and prepuce, but it can also cause scrotal and testicular hemorrhage and possibly even testicular rupture. 16 If considerable intratesticular hemorrhage occurs, it will be followed by focal necrosis, thereby compromising testicular function. Rupture or laceration of the tunica albuginea surrounding the testicle results in extensive hemorrhage (hematocele) and often in complete loss of testicular function. 16 The scrotum should be inspected carefully for any lacerations or puncture wounds. Swelling associated with the inflammatory process often will impede the ability of the clinician to effectively palpate the testes, thereby differentiating the cause of the scrotal enlargement. Fluid in the scrotal skin produces pitting, whereas fluid accumulation within the vaginal cavity (hydrocele) produces fluctuance. Palpation per rectum of the internal inguinal rings is indicated to rule out the possibility of an inguinal hernia. Ultrasonographic examination of the scrotum and contents provides a wealth of information regarding the nature of the scrotal swelling and contents. Differentiation of scrotal herniation, hematocele, scrotal skin

7 REPRODUCTIVE EMERGENCIES IN THE STALLION 677 edema, and testicular tumor may be possible using this diagnostic aid. Imaging the scrotal contents provides much information regarding the site of testicular damage and the type of lesion. Normal testicular parenchyma is homogenous with medium-level echogenicity and distinct borders. Testicular edema is recognized as diffusely hypoechoic areas within the testicular parenchyma. Recent hemorrhage produces hyperechoic areas of blood accumulation, but this image changes as the clot forms. Organizing hematomas produce anechoic areas interspersed with hyperechoic fibrin strands. Scar formation is associated with hyperechoic regions. 16 After ultrasonographic evaluation, the authors have been able to confirm the presence of an infectious process by performing an aseptic aspirate of the tunic fluid. Extreme care must be exercised in performing a needle aspirate. Strict aseptic technique is essential to minimize the risk of bacterial introduction. Another potential complication is an iatrogenic hematocele if the needle ruptures a vessel on the surface of the tunica albuginea. Early and repeated application of short-term (20 minutes every 1-3 hours) cold therapy can effectively reduce: the severity of local inflammation and edema. 16 Cold water can be applied from a hose or a bag of crushed ice may be held against the scrotum. It should be noted that prolonged or excessive application of cold therapy will itself cause skin damage, and actually contribute to the inflammation and localized swelling. 16 Thus, although hydrotherapy is useful, the clinician should be cognizant of the possibility of causing maceration of scrotal skin. Emollient ointment (e.g., lanolin, glycerine, petrolatum) should be applied to the scrotal skin to protect it against maceration. 1 Systemic antibiotic and anti-inflammatory therapy should be initiated and tetanus prophylaxis should be checked. Diuretics may be administered, although their effectiveness in treating localized inflammatory edema is questionable. Severe damage and hemorrhage to one side of the scrotum is treated by unilateral castration in an attempt to rapidly reduce the inflammatqry response before the other testicle is affected. Removal of the injured testicle often results in compensatory hypertrophy in the remaining testicle. Strict aseptic technique is critical to prevent any postoperative complications that could damage the remaining testicle. Chronic changes to the scrotal architecture may affect testicular thermoregulation adversely. The authors strongly suggest that a breeding soundness evaluation be performed 60 days after the condition has resolved. PENIS AND PREPUCE Penile Trauma and Paraphimosis Direct trauma to the penis generally occurs during breeding attempts when the penis is fully erect. Instances include kicks from a mare; tail hair abrasions; lacerations from a caslick's or breeding stitch; contact

8 678 PERKINS & FRAZER with a solid object (e.g., fence), or improperly fitted, cracked, or wrinkled phantom covers. Paraphimosis refers to the inability to retract the penis into the prepuce and may occur secondary to penile trauma, neoplasia, priapism, or paralysis. 16 Penile and preputial trauma is rapidly followed by inflammatory edema. Typically, the swelling is most pronounced in the region of the preputial ring, and the ensuing prolapse will carry the penis with it. Gravitational edema plays an important role in the pathophysiology of the worsening prolapse. If left untreated, the condition becomes selfperpetuating. Venous and lymphatic drainage are impaired greatly by the swelling and pendulous weight. Further complication can result from physical trauma occurring to the exposed organ. Although the diagnosis of paraphimosis is obvious, the primary underlying cause may not always be trauma. It is important to determine the incitirig cause, history of previous episodes of paraphimosis, and any recent history of medication especially tranquilization. 1 A careful examination of the penis and prepuce is performed, and manual replacement of the penis into the prepuce is attempted. The clinician must ascertain whether the animal can urinate. Catheterization of the bladder should be performed if the stallion has not been observed to urinate or if rectal palpation demonstrates a distended bladder. Breeding stallions should be isolated from mares to preclude any sexual stimulation. The initial goal of therapy is to provide penile support and resolve gravitational edema. If at all possible, the penis should be replaced within the prepuce and retained with a purse string suture or towel clamps placed near the preputial orifice. A preputiotomy may be indicated to facilitate replacement. It may be necessary to gently massage the penis to reduce the swelling. In some cases of severe penile edema the temporary application of an Esmarch bandage may force sufficient edematous fluid out to enable manual replacement of the penis within the preputial cavity. If attempts at replacement are unsuccessful, then the penis must be supported against the ventral body wall until penile edema is reduced. A sling may be made of loose mesh such as large-sized stockinette. It is then held in place with gauze or rubber tubing. One set of tubing is tied from the front of the sling over the flanks and tied over the dorsum of the back. The other set runs from the back of the sling between the stallion's hind legs and up beside the tail and is tied to the tubing over the horse's back. Alternately, bandages may be used to suspend the penis close to the ventral abdominal wall in the form of a belly wrap. Urine drainage is not facilitated as well with this method and may lead to excoriation of the penile skin. Any support should be removed twice a day and the penis examined, cleaned, and rubbed liberally with an emollient ointment. A variety of products have been used, including ointments containing disinfectants, antibacterial agents, and anti-inflammatory agents such as DMSO or corticosteroids. Cold therapy may be very useful during the acute phase of the condition and should be continued until the threat of further edema or hemorrhage has passed. A bag of crushed ice may be held against the

9 REPRODUCTIVE EMERGENCIES IN THE STALLION 679 affected area in a sling. Limited cold water hydrotherapy may be used initially as an aid to reduce edema. Subsequently, warm water hydrotherapy may be useful to encourage dispersal of the edema fluid. Excessive hydrotherapy will result in maceration of the penile epithelium, although emollient ointments help mitigate against this occurrence. The horse should be exercised daily to aid in edema reduction. Medical therapy includes tetanus prophylaxis, broad-spectrum antibiotics, NSAIDs, intravenous DMSO, and diuretics. The stallion should be monitored regularly until the penis can be retained voluntarily within the prepuce. Prompt care of an acute injury may resolve the inflammatory edema within 3 to 4 days. Protracted paraphimosis results in fibrotic enlargement of the prepuce and impedes penile retraction. Surgical removal of this scar tissue may be necessary to allow normal preputial function. Techniques of penile circumcision (Reefing operation) have been described previously.!3 It is important to remember that associated damage to either the cavernous sinuses or the nervous supply to the penis may impair the ability of the stallion to achieve an erection and to copulate successfully. Permanent replacement of the penis within the prepuce (phallopexy) or penile amputation (phallectomy) can be performed as a salvage procedure in animals with unresponsive paraphimosis. Techniques for these procedures have been described previously. to Superficial penile lacerations and abrasions should be left to heal as open wounds. Surgical debridement and suturing under general anesthesia should be performed in cases of deep or extensive lacerations of the penis, especially if the laceration penetrates either the corpus cavernosum penis (CCP), corpus spongiosum, or urethra. Sexual rest is essential until healing is complete. In extreme cases, penile amputation may be necessary. Apart from direct trauma, penile hematoma may occur when the penis is inadvertently bent during a copulatory thrust. This may happen as a result of poor penile positioning during natural mating or when the penis is deflected for semen collection into an artificial vagina. The bleeding is generally from ruptured vessels external to the tunica albuginea of the penis, in contrast to the condition in the bull in which hematomas invariably originate from rupture of the tunica albuginea, allowing hemorrhage directly from the CCP. Contained hemorrhagic episodes produce rapid and often extensive swelling in the subcutaneous tissue of the prepuce and penis. The associated inflammatory swelling and edema then result in paraphimosis. Approach to therapy should be as outlined for paraphimosis. Application of temporary pressure bandages to the penis may help to reduce continued hemorrhage. If the hematoma continues to expand despite therapy, a tear involving the CCP should be suspected, and an exploratory surgery should be performed under general anesthesia to evaluate the integrity of underlying tissue. 16 Once penile hematoma has resolved and.the penis can be voluntarily retracted within the prepuce, it is important to continue physical therapy to minimize the risk of restriction of normal penile function as a result of scar tissue formation. The penis should be massaged daily with emollient

10 680 PERKINS & FRAZER ointment and the stallion exposed to mares after 3 weeks to assess his ability to achieve a normal erection. In some cases, penile anesthesia follows hematoma or trauma to the dorsum of the penis. This may interfere with the animal's ability to ejaculate. If a fibrotic ring remains after resolution of a penile hematoma, this can be removed by means of a reefing operation. Penile Paralysis and Priapism The terms paralysis and priapism describe different conditions, but the common result is a penis in varying degrees of engorgement that protrudes from the prepuce. It is appropriate to differentiate between the two conditions because treatment options do vary for each condition. Inability to retract the penis is rapidly followed by the development of gravitational edema; the condition then progresses to paraphimosis with resultant severe necrotic changes to the pendulous penis. The underlying pathology is assumed to be a defect in the neuromuscular and vascular control mechanisms, influencing penile vascular engorgement, and in the function of the retractor penis muscle. 8 Priapism is a prolonged erection associated with engorgement of the CCP in the absence of any sexual desire. 2 Normal erection results from parasympathetic stimulation of arteriolar flow into the penis. lo A loss of cholinergic stimulation and an increase in adrenergic stimulation will diminish penile arteriolar blood flow and promote venous outflow from the CCP. This causes detumescence. Excessive cholinergic stimulation and failure of adrenergic stimulation may then result in priapism. Increasing CO 2 tension within the stagnating blood cells of the CCP results in the erythrocyte sludging and occlusion of the venous outflow from the cavernous sinuses. Outflow obstruction is enhanced by generalized edema of the penis and prepuce. Irreversible fibrotic obstruction to arteriolar inflow and venous outflow is the final result of prolonged priapism. Ultrasound examination of affected horses shows distension of the CCP with thrombosed blood. The cross-sectional image of the affected penis has a uniform, echogenic appearance. Priapism occurs most commonly in the stallion, but it has also been reported to occur in geldings. The mechanism of action of phenothiazine tranquilizers remains uncertain but may be by blockade of the central and peripheral a-adrenergic and dopaminergic receptors that mediate detumescence. 5 The effect is unpredictable and seems to be unrelated to the dose given. Horses with elevated circulating levels of epinephrine (fear, stress) are more susceptible to the hypotensive effects of phenothiazine tranquilizers. The authors prefer not to use acepromazine in valuable breeding stallions or in animals that are excited or have an erection at the time of administration of the tranquillizer or sedative. Management of the horse with priapism includes symptomatic and specific treatments. Symptomatic therapy is the same as for cases of paraphimosis. Medical therapy may be initiated with antibiotics,

11 REPRODUCTIVE EMERGENCIES IN THE STALLION 681 NSAIDs, DMSO, and diuretics.16 Successful treatment of priapism has been reported in horses given a cholinergic blocker (8 mg benztropine mesylate by intravenous injection) within 2 hours of onset of the conditiony' 17 Subsequent use of the drug in a stallion 4 days after onset of priapism was unsuccessfuu6 A stepwise approach to treatment as proposed by Schumacher and Hardin 8 is recommended by the authors. Benztropine mesylate therapy should be administered as soon after diagnosis as is possible. If no response is observed within 24 hours, the horse should be placed under general anesthesia and the CCP should be flushed with heparinized saline to clear sludged erythrocytes. If priapism recurs after this procedure, it is likely to be a result of continuing occlusion of venous outflow from the CCP and a vascular shunt should then created between the CCP and the corpus spongiosum to provide an outflow path for erythrocytes. These techniques have been described previously.lo Few data exist documenting the efficacy of these techniques in the stallion, and the prognosis for return to reproductive function is considered to be poor. Thus, heroic attempts at resolving priapism should only be considered in valuable breeding ariimals. Successful collection of semen has been reported in stallions that are unable to maintain an erection, although varying degrees of assistance are likely to be required. Penile paralysis is used to describe a condition in which the nonerect penis protrudes from the prepuce with no attempt made to retract the penis. Cases have been reported after sedation with phenothiazine derivatives, spinal cord disease (rhinopneumonitis, rabies, bacterial infection, equine protozoal myelitis, neoplasia, and spinal trauma), after use of reserpine, in debilitated or exhausted horses, and associated with purpura hemorrhagica.16 Cases of penile paralysis have been reported in horses debilitated because of concurrent malnutrition, parasitism, glucose malabsorption, and salmonellosis.1 2 Penile paralysis may occur in conjunction with priapism. Treatment of paralysis involves supportive care of the penis and symptomatic medical therapy as outlined for paraphimosis. A complete physical examination, with supportive laboratory tests, should be performed to identify any concurrent disease that may be contributing to the penile paralysis. Specific treatment of any underlying condition contributing to the etiology is required. In some cases, complete resolution of the penile paralysis follows successful treatment of the primary etiological condition. Permanent replacement of the penis within the prepuce (phallopexy) or penile amputation (phallectomy) should be considered for animals that are not valuable breeding stallions or for refractory cases of priapism or paralysis. Techniques for these procedures have been described.lo POSTHUMOUS COLLECTION OF SPERMATOZOA The untimely death of a valuable breeding stallion results in considerable loss of genetic potential. Harvesting the testes from stallions likely

12 682 PERKINS & FRAZER to die-or after death-may make it possible to recover a sufficient number of spermatozoa to enable several mares to be bred by artificial insemination. If no estrous mares are available, an attempt at semen freezing using conventional techniques of cryopreservation may be warranted. Although sperm motility and viability will decrease steadily after the animal's death, recent data suggest that spermatozoa flushed from epididymal tubules as much as 24 hours after death are still capable of fertilization. 3 Based on this information, it may be worthwhile to harvest the testes for up to several hours after death. The testes should be transported in phosphate buffered saline (PBS) solution at room temperature or slightly chilled. Motile sperm are most likely to be recovered from the tail of the epididymis and the vas deferens. The cauda epididymis is separated from the remainder of the epididymis and then is carefully dissected to free the single epididymal tube. Sections of epididymis are then flushed by syringing PBS or equine semen extender at room temperature. An alternative technique is to macerate the epididymal tail with a scalpel, immerse the sections in PBS, and then gently agitate the mixture to allow spermatozoa to separate and enter the PBS. Fluid containing the flushed or isolated spermatozoa may then be centrifuged and resuspended in equine semen extender. Few data exist on the usefulness of this technique in the horse. The authors have successfully achieved pregnancies by artificially inseminating mares with spermatozoa that had been harvested from the testes of stallions that were euthanatized for medical reasons. References 1. Clem M, DeBowes R: Paraphimosis in horses-part II. Compend Contin Educ Pract Vet 11: , Donawick W, Reef V: Priapism: A case history in a stallion. In Proceedings of the Annual Conference of the Society for Theriogenology, Couer d'alene, ID, 1989, pp Garde J, Aguado M, Perez S, et al: Physiological characteristics of epididymal spermatozoa from postmortem rams. Theriogenology 41:203, Hunt R: Management of complications associated with equine castration. Compend Contin Educ Pract Vet 13: , Muir W: Standing chemical restraint in horses. In Muir W, Hubbell J (eds): Equine Anesthesia. St. Louis, Mosby Year Book, 1991, pp Roberts S: Veterinary Obstetrics and Genital Diseases (Theriogenology). Woodstock, VT, Roberts, Robertson J: Diseases of the small intestine. In White N (ed): The Equine Acute Abdomen. Philadelphia, Lea & Febiger, 1990, pp Schumacher J, Hardin D: Surgical treatment of priapism in a stallion. Vet Surg 16: , Schumacher J, Schumacher J, Spano JS, et al: Effects of castration on peritoneal fluid in the horse. J Vet Int Med 2:22-25, Schumacher J, Vaughan J: Surgery of the penis and prepuce. Vet Clin North Am (Equine Pract) 4: , Sharrock A: Reversal of drug induced priapism in a gelding by medication. Aust Vet J 58:39-40, Simmons H, Cox J, Edwards G, et al: ParaphimOSiS in seven debilitated horses. Vet Rec 116: , 1985

13 REPRODUCTIVE EMERGENCIES IN THE STALLION Turner A, McIlwraith C: Techniques in Large Animal Surgery, ed 2. Philadelphia, Lea & Febiger, 1989, pp Threlfall WR, Carleton CL, Robertson JT, et al: Recurrent torsion of the spermatic cord and scrotal testis in a stallion. J Am Vet Med Assoc 196: , Van Der Velden M, Rutgers J: Visceral prolapse after castration in the horse: A review of 18 cases. Equine Vet J 22:9-12, Varner D, Schumacher J, Blanchard T, Johnson L: Diseases and Management of Breeding Stallions. Goleta, CA, American Veterinary Publications, Wilson D, Nickels F, Williams M: Pharmacologic treatment of priapism in two horses. J Am Vet Med Assoc 199: , 1991 Address reprint requests to Grant S. Frazer, BVS, MS Department of Veterinary Clinical Sciences College of Veterinary Medicine The Ohio State University 601 Tharp Street Columbus, OH