Manually assisted ejaculation in a stallion with subsequent to paraphimosis

Charles C. Love, DVM; Sue M. McDonnell, PhD; Robert M. Kenney, DVM, PhD

enile dysfunction is a common sequelae of pri- set, the corpus cavernosum penis had been flushed Papism, penile paralysis, and paraphimosis in to remove blood clots. Additional treatments in- association with debilitation,1,2 anesthesia,3-9 and cluded systemic administration of penicillin, trauma.10,11 Two distinct aspects of penile dys- gentamicin sulfate, furosemide, vitamin B, dexa- function are inability to retract the penis and methasone, and trichlormethiazide. Afterward, the inability to achieve erection. Loss of erectile func- stallion had not been observed to achieve an erec- tion can range from moderate to severe.12 In a tion or to fully retract the penis. stallion with reset-pine-related penile paralysis and On initial examination at 8 months after onset paraphimosis,6 the penis reached approximately of the problem, the penis persistently protruded 7 normal length and diameter with partial erection. to 10 inches from the prepuce. It was of normal Semen was collected from this stallion by use of a shape, flaccid, and free of lesions and scars. Palpa- Missouri model artificial vagina. Similarly, a stal- tion of the shaft of the penis revealed 2 bilateral fi- lion that had penile paralysis in association with brous cord-like structures corresponding to the debilitation2 responded with pelvic thrusting and corpora cavernosa. The skin of the shaft and glans ejaculation when the extended, flaccid penis was penis were free of thickening and keratotic changes placed in an artificial vagina. In both of these cases, typically associated with chronic pendulous expo- the penis appeared normal with respect to size and sure of the penis. Ultrasonogsaphy of the base, sensitivity. In some cases, it has appeared that shaft, and revealed that the area corre- changes in sensitivity of the shaft and glans of the sponding to the corpora cavernosa extending from penis have limited the stallion’s response to an ar- the glans to the level of the scrotum to be densely tificial vagina.13 In the past, the prognosis for suc- echogenic. Further proximal, the cavernous tissue cessful breeding of stallions with this condition has appeared to have a normal echogenic pattern. been poor. The stallion of this report was success- When the stallion was sexually aroused, the penis fully returned to stud, despite severe loss of both increased slightly in diameter, but the exposed erectile function and sensitivity of the glans and portion remained flaccid. shaft of the penis. The stallion was unusually excitable at rest as An 8-year-old Thoroughbred stallion with an well as when exposed to a mare. The stallion also 8-month history of erectile dysfunction and para- exhibited stall-walking, a repetitive back and forth was referred for reproductive evaluation pacing routine in his stall, primarily in association with the goal of determining potential for returning with activity in the barn. When exposed to a mare, to breeding by natural service. Prior to the onset of the stallion became highly aroused, would rear, the condition, the stallion was used for breeding 2 strike, and charge toward the mare. An effort was years, siring 32 foals the first year. The number of made to control the stallion in a manner that would foals born in the second year was unknown, but the not inhibit the high level of arousal, yet would per- pregnancy rate was reported to be satisfactory. The mit safe handling in the breeding situation. stallion had been observed to have an erection be- Evaluation of the stallion’s ability to ejaculate fore being loaded on a van for transport to a vet- revealed that in response to manual stimulation of erinary hospital for minor orthopedic surgery un- the glans and shaft or to an artificial vagina, he did der general anesthesia. Following the stallion’s not respond with normal thrusting, despite various recovery from general anesthesia, the penis was levels of temperature and pressure. The penis was prolapsed and rigid. During the acute stage, the small and flaccid, making it difficult to insert into stallion had been given warm and cold hydrother- the artificial vagina. The most vigorous coupling apy to the penis. At 10, 13, and 14 days after on- and thrusting responses were elicited by manual stimulation with warm towel compresses14,15 after From the Section of Reproductive Studies, School of Veter- inary Medicine, New Bolton Center, 382 W Street Rd, Univer- mounting. This was accomplished with the opera- sity of Pennsylvania, Kennett Square, PA 19348. tor’s left hand grasping the distal portion of the

JAVMA, Vol 200, No. 9, May 1, 1992 Clinical Reports 1357 shaft near the glans and the right hand applying vaginal liner, extending from the vulva to the steady, firm circumferential pressure with the internal os of the cervix. The spilled semen was compress to the base of the penis in the region of then aspirated for infusion into the uterus as rein- echogenically normal cavernous tissue. Thrusting forcement breeding, according to breed associa- was most vigorous in response to hot (45 C) com- tion rules. presses. The stallion responded more vigorously to The referring veterinarian was instructed in a live mount mare than to a dummy. In 4 training the technique of manual stimulation, and the stal- sessions (15 to 30 minutes) over a 10-day period, lion was returned to stud. With the vaginal liner the stallion showed consistent, vigorous coupling and use of the manual stimulation breeding aids, and thrusting, but failed to ejaculate. The stallion the stallion was bred to 20 mares, 18 of which were was tolerant of manipulation, maintained excellent subsequently confirmed pregnant. libido, and displayed otherwise normal sexual be- There are several reports of stallions with havior. erectile dysfunction being bred by artificial insem- In an attempt to lower the ejaculatory thresh- ination.1,6,12 To our knowledge, the return to nat- old, gonadotropin-releasing hormonea (GnRH; 50 ural service of a stallion with severe erectile µg, SC) was administered at 2 hours and again at 1 dysfunction has not been reported. Even when a hour before breeding. Following the first treat- stallion does not respond to an artificial vagina, it ment, the stallion ejaculated on the first mount, may be possible to elicit ejaculation with manual using the breeding routine described. The level of stimulation of the base of the penis. This is consis- sexual arousal appeared higher than without treat- tent with observations that glans stimulation is not ment, and the penis, although remaining flaccid, a prerequisite for ejaculation.19 In our laboratory, appeared to elongate somewhat during teasing. it has been found (SMM) that stallions trained to The stallion was given GnRH treatment before each respond to manual stimulation for collection of se- 15 of 3 more collection attempts at l- to 2-day inter- men will thrust and ejaculate with the penis flac- vals. The stallion ejaculated on 2 occasions, in 3 cid. In the stallion of this report, ejaculatory func- and 2 mounts, respectively, and within <5 minutes tion seemed to be enhanced by tight constriction on each occasion. Ejaculation occuqed with the of the base of the penis. Increased pressure on the normal sequence of semen and gel fractions. The corpora cavemosa proximal to the point of manual sperm morphologic characteristics were approxi- constriction may have approximated that which mately 70% normal, with progressive motility also occurs with normal erection, and thus have facil- 70%. itated the ejaculatory reflex.20 Over the next 2 weeks, the manual stimulation An important aspect of this case was the stal- procedure was repeated 8 times, without GnRH lion’s strong libido. He achieved and maintained a treatment. The stallion was teased with a mare next high level of excitement during initial breeding at- to his stall for at least 10 minutes before being taken tempts and subsequent manipulations. Initially, his to the breeding shed. This resulted in a level of excitable nature made him a challenge to handle, sexual arousal similar to that following treatment but this excitable nature appeared to play a posi- with GnRH. On each occasion, the stallion ejacu- tive role in that he persistently remounted and tol- erated necessary manipulations. In another re- lated after 1 to 10 mounts in less than 15 minutes. 12 Sexual behavior, including the number of mounts port, the importance of patience when retraining and thrusts, as well as latency to ejaculation were stallions with incomplete erection was stressed. 16 within the range of normal. The ejaculates were This case also highlights the progress that can be collected by use of a funnel attached to a bottle17 made with a systematic, patient approach. The first and evaluated according to Kenney et al.18 All se- ejaculation was reached 10 days after admission, men measures were within normal ranges. and with <2 hours of actual training time in the A method for breeding was developed that breeding shed. Daily ejaculation was established would satisfy breed association requirements for within the next 10 days and with

1358 Clinical Reports JAVMA, Vol 200, No. 9, May 1, 1992 3. Jones RS. Penile paralysis in stallions (letter). J Am Vet 14. Crump J Jr, Crump J. Stallion ejaculation induced by Med Assoc 1966;149:124. manual stimulation of the penis. Theriogenology 1989;31:341- 4. Pearson H, Weaver BMQ. after sedation, 346. neuroleptanalgesia and anaesthesia in the horse. Equine Vet J 15. McDonnell SM. Love CC. Manual stimulation collec- 1978;10:85-90. tion of semen from stallions: training time, sexual behavior, and 5. Lucke JN, Sansom J. Penile erection in the horse after semen. Theriogenology 1990;33:1201-1210. acepromazine. Vet Rec 1979;105:21-22. 16. McDonnell S. Reproductive behavior of the stallion. 6. Memon MA, Usenik EA, Vamer DD, et al. Penile pa- Vet Clin North Am Equine Pract 1986;2:535-555. ralysis and paraphimosis associated with reserpine administra- 17. Love CC, Loch WL, Bristol F, et al. Comparison of tion in a stallion. Theriogenology 1988;30:41l-419. pregnancy rates achieved with frozen semen using two packag- 7. Lloyd KCK, Harrison I, Tulleners E. Reserpine toxico- ing methods. Theriogenology 1989;31:613-622. sis in a horse. J Am Vet Med Assoc 1985;186:980-981. 18. Kenney R, Hurtgen J, Pierson R, et al. Manual for 8. Wheat JD. Penile paralysis in stallions given propio- clinical fertility evaluation of the stallion. Hastings, Neb: Society promazine. J Am Vet Med Assoc 1966;148:405-406. of Theriogenology, 1983. 9. Merkin TE. Priapism as a sequela of chlorpromazine 19. Tischner M, Kosiniak K, Bielanski W. Analysis of the therapy. JACEP 1977;6:367-368. pattern of ejaculation in stallions. J Reprod Fertil 1974;41:329- 10. Clem MF, DeBowes RM. Paraphimosis in horses- 335. Part I. Compend Equine 1989;11:72-75. 20. Marberger H. The mechanisms of ejaculation. Basic 11. Clem MF, DeBowes RM. Paraphimosis in horses- Life Sci 1974;4:99-110. Part II. Compend Equine 1989;11:184-187. 21. McDonnell SM. DiehI NK, Garcia MC, et al. Gonad- 12. Neely DP. Physical examination and genital diseases otropin releasing hormone (GnRH) affects precopulatory be- of the stallion. In: Morrow DA, ed. Current therapy in therio- havior of testosterone-treated geldings. Physiol Behav 1989; genology: diagnosis, treatment and prevention of reproductive dis- 45:145-149. eases in animals. Philadelphia: WB Saunders Co, 1980;694-706. 22. Pozor MA, McDonnell SM. Kenney RM, et al. GnRH 13. Walker DF, Vaughn JT. Bovine and equine urogenital facilitates copulatory behavior in geldings treated with testoste- surgery. Philadelphia: Lea & Febiger. 1980;125-144. rone. J Reprod Fertil Suppl 1991;44:666-667.

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