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Ischial urethrostomy is a viable treatment option for feedlot steers (≥318 kg) and breeding bulls [4, 32]. This procedure is performed under standing epidural anesthesia. The perineal region from the anus to the base of the scrotum is aseptically prepared. A 10‐cm midline skin incision is performed starting over the ischial arch approximately 5 cm ventral to the anus [4]. The dense layer of fascia between the skin and retractor penis muscle is incised to expose the retractor penis muscle [4]. Blunt dissection between the retractor penis muscles reveals the bulbospongiosus muscle [4]. The urethrotomy incision is made through the bulbospongiosus muscle or just distal to its attachment [33]. Excessive hemorrhage is common during this procedure if the urethra incision is off midline and the corpus spongiosum is nicked. A 20‐ to 28‐French Foley catheter is advanced into the bladder. Entrance into the bladder can be assisted with the use of a rigid stylet or curved hemostats to direct the tip over the ischial arch [4]. The Foley balloon is distended with saline and retracted until it is seated into the trigone of the bladder and sutured in place where it exits the skin. A one‐way valve utilizing the fingertip of a glove with a slit should be taped onto the external end of the Foley catheter to prevent air aspiration into the bladder and minimize bacterial contamination. Ideally, impervious plastic should be adhered to the skin just ventral to the anus to prevent fecal contamination of the surgical site. For breeding bulls in which urethral patency is desired, a sterile bandage over the incision with stay sutures and surgical towels is recommended (Figure 20.7).

Figure 20.7 Placement of a plastic or rubber (source‐ automobile inner tube) strip sutured to the perineum dorsal to the surgery site is recommended.

Source: Image courtesy Dwight Wolfe and Misty Edmondson.

For feedlot steers, the catheter can remain in place until desired slaughter weight is reached or the uremia is resolved (~30 days) [32]. Additionally, this procedure can be used when a previous lower perineal urethrostomy site has strictured or reobstructed. In general, the prognosis is greatly reduced for individuals with bladder rupture. However, this technique allows the bladder to remain empty and heal by second intention.

This technique can be a good option of urinary diversion for breeding bulls (without urethral rupture) because the urethral diameter is larger in this region, thus decreasing the risk of urethral stricture. If urethral patency is immediately obtained after the procedure, the Foley catheter can be removed and 3 mm polyethylene tubing is inserted through the urethrotomy incision into the bladder and exiting the distal urethra [4]. A primary urethral closure should be performed and the catheter exiting the distal urethra should be sutured to the ventral abdomen with a Chinese finger cuff ligature [4]. If urethra patency is not immediately obtained, the Foley catheter should remain in place to allow for relief of urethral spasm and swelling. If the obstruction fails to resolve after three to five days, alternative methods of calculi removal should be implemented. Other methods include retrograde catherization and hydropulsion, urethroscopy and possible basket retrieval, chemolysis (Walpole's solution, acetic acid, or hemiacidrin) for phosphatic uroliths (struvite or apatite), or urethrotomy. Long‐term outcome and complication rates for breeding bulls have not been evaluated. However, there is one report of a goat with a strictured perineal urethrostomy being reversed with a buccal mucosal graft urethroplasty successfully [34].