Penile and Preputial Abnormalities
Examination of the penis is most easily performed with the buck positioned on his rump. Tranquilization may be helpful, because goats rarely rest quietly in the sitting position.
The shaft of the penis is pushed anteriorly with one hand while the prepuce is pushed posteriorly with the other hand. The young buck kid is held in a sitting position in the examiner’s lap, with legs pointing away from the person, to facilitate exteriorization and examination of the penis.Malformations
Most congenital malformations - i.e., hypospadias (Al-Ani et al. 1998, Azari et al. 2010), shortened penis of some intersexes - are easily detected by physical examination. Congenital diverticula in the urethra were associated with swelling of the ventral sheath and continuous dribbling of urine in 16 goat kids 2-6 months of age in India; 10 of these animals also had a completely divided scrotum. The animals recovered after surgical excision of the diverticula (Gahlot et al. 1982). In Iran, 36 male kids with hypospa- dias/urethral diverticula, mostly from herds that had grazed in pistachio orchards, were successfully treated by surgical creation of a permanent urethrostomy. Phytoestrogens in the pistachios were hypothesized as a possible cause of the defects (Azari et al. 2010).
Maturation of the Penis
When the sexual maturity of a male is questioned (e.g., during a breeding soundness exam or when he has inadvertently gained access to females that were not to be bred), the penis should be carefully examined. As long as the urethral process and glans penis are adhered to the prepuce, successful copulation is unlikely to occur. These adhesions, normal in the immature buck, break down with testosterone, time, and good nutrition.
Injuries
Traumatic hematoma of the penis is rare in small ruminants; a single case report describes successful surgical treatment in a buck with return to normal breeding (Bani Ismail and Ababneh 2007).
The presence of a hair ring (accumulation of loosely matted hairs) around the shaft of the penis may be accompanied by irritation (Tarigan et al. 1990). Grass awns in the prepuce can also cause irritation.Loss of the urethral process is a common shearing accident in Angoras. If the urethral process is absent but the glans penis is intact and normal, no direct adverse effect on fertility is expected (Ott 1978). In other goat breeds, a previous bout of urolithiasis is usually responsible for loss of the urethral process. Reobstruction at a later date may endanger the buck’s life or fertility. There also might be an increased risk of contamination of the semen by urine, caused by damage to sphincter muscles during obstruction. There is a single report of erection failure in a Nubian buck after urolithiasis, secondary to a vascular obstruction in the corpus cavernosum penis (Todhunter et al. 1996). Urolithiasis is discussed in Chapter 12.
Posthitis
Posthitis, the inflammatory condition of the prepuce also termed “pizzle rot,” often results from overgrowth of urea- splitting bacteria in the prepuce of males consuming excessive dietary protein. Free ammonia scalds the preputial and penile mucosa. Wethers appear to be more susceptible than intact males (Shelton and Livingston 1975). This condition is discussed in Chapter 12.
Pustules and ulcers on the prepuce and penis of bucks have been ascribed to caprine herpesvirus-1, which is associated with abortion and with vulvovaginitis in does (Tarigan et al. 1987; Uzal et al. 2004; Camero et al. 2015). The gross appearance varies with the extent of secondary bacterial infection. Histologically, findings of acidophilic intranuclear inclusion bodies and chromatin margination in epithelial cells adjacent to the ulcers are considered highly suggestive of the herpesvirus infection (Tarigan et al. 1990). It is also reported that bucks that spread the infection to does during mating may remain free of clinical signs (Grewal and Wells 1986).
This condition is discussed further in Chapter 12.Trichomoniasis
Trichomonad protozoa have been observed in large numbers in the semen of Alpine and Saanen bucks in France and Sardinia and in Angoras in South Africa. The parasite, which is approximately the size of a sperm head, infests the sheath and urethra. Quantity and quality of ejaculates are decreased, as is libido. The infections have been treated successfully with dimetridazole (3 or 5 g, divided into three intravenous doses at 24-hour intervals), but use of this drug is currently illegal in goats in the United States. Routine treatment of all bucks in the artificial insemination centers in France each summer, before the season of semen collection, has been proposed as an alternative to repeated testing of each buck (J.M. Corteel, Nouzilly, France, personal communication 1991). Effects of this organism on the doe have not been elucidated and recent reports of the condition are lacking.