retraction/extension can be performed.
Hematoma
Hematoma of the penis is probably the most common injury of the penis. This injury occurs when the penis misses the intended target, hits the cow's perineum, and bends. Although it usually occurs in young inexperienced bulls [411–13] it can also occur in the older bull, which due to orthopedic injury or pain has altered his approach during mounting. From a seasonal standpoint, it usually occurs early in the breeding season when the bull is an aggressive breeder and a large number of females may be cycling, or conversely late in the breeding season when the bull may be fatigued and perhaps has lost body condition and is not as athletic or becomes awkward or clumsy during his breeding attempts. The hematoma results due to rupture of the tunica albuginea and subsequent hemorrhage from the corpus cavernosum. The initial volume of blood escaping is less than 250 ml [4], but the size of the resultant hematoma varies as each subsequent erection results in further hemorrhage. Thus the hematoma may range in size from 15 to 30 cm. The resultant swelling occurs in the sheath over and cranial to the rudimentary teat (Figure 19.55). A prolapsed prepuce often results and this in fact may be the owner's reason for seeking help. Diagnosis may be aided with ultrasound, but, typically, a diagnosis is made from history and physical diagnosis. Do not attempt to aspirate the swelling, as inadvertent introduction of bacteria can convert a hematoma to an abscess.
Figure 19.55 Hematoma location.
Approximately 50% of bulls with rupture of the tunica albuginea return to breeding soundness without surgical repair of the injured penis. Conservative therapy consisting of absolute sexual rest for a minimum of 60 days (and avoiding extension of the penis) with systemic antibiotic therapy for the first 7–10 days is recommended. Daily hydrotherapy of the swollen sheath may stimulate circulation to the damaged tissues and assist with resorption of the edema and blood clot within the elastic tissues. If preputial prolapse is present, an emollient ointment should be applied and the protruding tissues protected with a support bandage or sling to prevent secondary trauma. The bull should have a complete BBSE prior to returning to service.
If surgery is to be performed, 5–7 days post occurrence has been shown to be the optimal timeframe [5]. Given that the owner or attendant typically may not notice this problem for 2–3 days and a 36‐ to 48‐hour fast must occur prior to surgery, surgery must be scheduled immediately in an attempt to fit that best timeframe. Timely surgical correction avoids the clot organization and fibrosis that begins to occur 10 days post injury. Once the decision is made to attempt surgical correction, antibiotic therapy is instituted if not already begun and feed is removed. The bull is fasted for 36–48 hours and water withheld overnight. General anesthesia can be utilized or regional anesthesia with heavy sedation [14]. Either way, the bull is tabled in right lateral recumbency, with the left hind leg pulled back and up and fastened securely. The surgical area is prepped and a vertical incision 20–25 cm long is made just cranial to the rudimentary teat. Careful dissection, attention to hemostasis, and manual removal of the blood clot follow. Lavage with a warm saline + Betadine Prep Solution™ aids in the removal of additional clots and, coupled with blunt dissection, identification of the lesion (Figure 19.56). Careful blunt or manual dissection is not just preferred over scalpel or scissor dissection but mandatory, as injury to the area vasculature and nerves must be avoided. Specifically, the area near the dorsal nerve of the penis must be avoided. Since identification of this area can be confusing as penile manipulation changes the anatomical context, it is useful to identify the urethra which is on the ventral aspect of the penis and thus 180° from the dorsum.
Figure 19.56 Rent in tunica albuginea.
After the tear or rent is identified, carefully lavage the area again and debride the often tattered edges of the rent. This must be minimal as excessive removal of tissue complicates closure and following healing there is the potential that the bull will have trouble extending his penis. Closure of the defect with No. 1 polyglycolic acid (PGA) in a bootlace pattern is the long‐standing recommendation and justifiably so, as there is enough wound tension to make simple interrupted suture patterns problematic. The elastic layers over the penis can be closed with 3–0 chromic gut in a simple continuous pattern. The penis is then returned to its normal position within the sheath and the surgical field is irrigated with warm 3% povidone–iodine in saline. Gently remove remaining blood clots. The subcutaneous tissues are closed with 0 chromic gut and the skin can be closed with 6‐mm Braunamid, typically with a Ford interlocking pattern. Antibiotics are continued for 5–7 days. The bull should have 60–90 days of sexual rest following surgery. Continue treatment of preputial prolapse as needed, but this condition usually resolves spontaneously within one week after surgery in B. taurus bulls. In B. indicus bulls the preputial prolapse may persist for longer than two weeks. In either case, it is wise to evaluate them for secondary damage to the prolapsed tissues. Seroma formation occurs often enough that it probably should not be considered a true complication. Complications include abscessation, suture dehiscence, shunts, permanent analgesia to the penis, and reoccurrence during the subsequent breeding seasons [2, 14]. Permanent analgesia may be the result of the original injury or an injury that occurs even following surgical resolution of the hematoma. In this later instance, the bull, having returned to service, sustains penile analgesia after breeding a few cows. Best evidence suggests that there are adhesions that surround portions of the nerves along the distal bend of the sigmoid flexure. These adhesions are not severe enough to restrict extension of the penis, but following repeated breeding they tear enough to damage the nerves [14].
Penile Deviations
Deviations of the penis may occasionally prevent intromission and coitus. Bovine penile deviations are classified as spiral (corkscrew), ventral, or S‐shaped [415–19]. Typically, bulls have had one or more successful breeding seasons prior to development of penile deviations with usually no known history of previous penile injury. Most bulls with these conditions are three or four years old and occasionally a bull over that age will develop penile deviation.
Spiral Deviation
Spiral deviation of the penis occurs more commonly than either ventral or S‐shaped deviations. One potential etiology involves malfunction of the dorsal apical ligament. The apical ligament, a thick collagen band, arises from the dorsum of the tunica albuginea about 2.5 cm proximal to the distal end of the prepuce and inserts into the tunica albuginea near the distal end of the corpus cavernosum penis (CCP). The function of this structure is to help maintain the shape of the penis during erection [17]. Historically, spiral deviations were considered to result from a short or inadequate apical ligament that slipped off to the left side of the penis at peak erection, allowing the penis to spiral and therefore preventing intromission [16–18].
However, the rapidly coordinated events leading to erection and the high maximum pressures within the CCP at ejaculation suggest that affected bulls may prematurely achieve maximum erection pressures prior to intromission. This suggestion may be supported by the fact that the penis of many normal bulls likely develops a spiral orientation in a cow's vagina during ejaculation [19]. Although the definitive cause of spiral deviations remains uncertain, apical ligament malfunction and premature achievement of high CCP pressure may be involved.
Many bulls develop spiraling of the distal penis during electroejaculation and masturbation [20]. Therefore
