a hemostat underneath the entire spermatic cord. The ductus deferens is then identified via palpation. The ductus deferens is a firm structure that runs medially along the spermatic cord and is approximately 2–3 mm in diameter. Once identified, the tunica vaginalis is carefully incised, utilizing extreme caution so as not to damage the cremaster muscle or pampiniform plexus resulting in excessive hemorrhage. After the tunica vaginalis is incised, the ductus deferens is isolated with another hemostat.
Two ligatures are placed approximately 3–5 mm apart using #0 absorbable suture [4, 5]. The ductus deferens is removed between the two ligatures. The skin is closed with a cruciate pattern using nonabsorbable suture. Antibiotics can be administered to prevent any postoperative infection, especially if surgical contamination has occurred. It is recommended to wait 30 days prior to using the bull as a teaser animal, since sperm can be present in the reproductive tract up to 30 days postoperatively [4, 5]. Additionally, it is recommended to perform yearly evaluations of the teaser animal's ejaculate to ensure sterility of the animal.
Epididymectomy
An epididymectomy is similar to a vasectomy with regard to restraint options and copulation behavior [6]. For this procedure, the base of the scrotum is clipped and aseptically prepared. Lidocaine 2% is infused over the tail of the epididymis. Once prepared, the surgeon grasps the neck of the scrotum and pushes the testicle ventrally. A 3‐cm incision is made over the tail of the epididymis through the skin and common vaginal tunic until the epididymis is exteriorized. The tail of the epididymis is carefully dissected from the testicle, and towel clamps or Allis tissue forceps can be used to assist in handling and manipulation of the epididymis. A hemostat is placed on the ductus deferens and the body of the epididymis. Ligatures with #0 absorbable suture are placed proximal to the hemostats. The tail of the epididymis is removed by transection distal to the hemostats. Figure 21.2 shows the procedure.
Figure 21.2 Procedure for epididymectomy.
Source: Illustration by Mal Hoover.
The common vaginal tunic is closed using #0 absorbable suture. The skin can be closed with non‐absorbable cruciate sutures or the incisions can be left open to allow ventral drainage. Antibiotics can be administered to prevent postoperative infections. Postoperative resting recommendations and yearly ejaculate examinations are the same as previously stated for vasectomy aftercare.
Penile–Prepuce Translocation
Penile–prepuce translocation (“sidewinder”) is the surgical transposition of the penis and prepuce from the ventral midline to the right or left flank of a bull. This procedure allows normal protrusion and erection but does not permit intromission. In general, “sidewinders” are preferred by producers due to longevity and herd retention of the teaser animal. Bulls with a penile–prepuce translocation maintain better and longer libido since this procedure allows normal protrusion and does not cause pain during erection. Some bulls are able to compensate and learn how to breed females despite the translocation of the penis and prepuce. Therefore it is recommended that a vasectomy or epididymectomy is performed to ensure sterility of the bull.
Penile–prepuce translocation is performed in lateral recumbency, so general anesthesia is the preferred method of restraint. If general anesthesia is not possible, heavy sedation with rope restraints and local infiltration of 2% lidocaine can be used. Ideally, food should be withheld for 24 hours and water for 12 hours before performing the procedure.
Prior to placing the bull in recumbency, the translocation site for the preputial orifice should be identified. The translocation site should be just outside the flank fold and lateral to the original preputial orifice site [3]. An 18‐gauge needle can be used to abrade the epidermis so the location is not altered after placing the animal in recumbency and skin stretching occurs. The ventral abdomen from the umbilicus to just cranial to the scrotum and the site of translocation of the flank should be clipped and aseptically prepared. Flush the prepuce with dilute iodine solution.
Before making the initial incision, place one simple interrupted suture at the dorsal aspect of the preputial orifice to serve as a marker and prevent twisting of the prepuce during translocation. A circumferential skin incision around the preputial orifice is made 4 cm from the orifice or a total diameter of 8–10 cm (Figure 21.3) [3, 4]. Extend the skin incision on the ventral midline from the preputial orifice to just cranial to the scrotum (Figure 21.4). Carefully dissect the penis and prepuce from the ventral abdomen. Avoid lacerating the prepuce; packing or tubing can be placed in the prepuce to aid with proper identification. While dissecting the penis and prepuce, avoid incising the dorsal penile vessels and control hemorrhage as it is encountered. Once the penis and prepuce are dissected, make a circular skin incision equivalent to the diameter of the preputial orifice at the desired translocation site (Figure 21.4). Use a sponge forceps to create a tunnel toward the flank incision. As the forceps is retracted, open it slightly to help facilitate penile translocation. This tunnel can also be accomplished with a cold sterilized polyvinyl chloride (PVC) pipe (Figure 21.5).
Figure 21.3 Circumferential incision 4 cm from the preputial orifice is performed with an interrupted suture placed at the dorsal aspect of the preputial orifice to prevent twisting during translocation.
Source: Photo courtesy of Tom Thompson.
Figure 21.4 Ventral midline incision extending caudally with circumferential incision at the translocation site.
Source: Photo courtesy of Tom Thompson.
Figure 21.5 Use of a cold sterilized PVC pipe to facilitate tunneling of penile translocation and skin incision for the translocation site.
Source: Photo courtesy of Tom Thompson.
Place a sterile glove or sleeve over the preputial orifice to minimize contamination of the subcutaneous tissues. Then run a sponge forceps from the flank incision to the ventral midline incision and grasp the preputial orifice. Manipulate the preputial orifice to the flank incision, taking care not to twist the prepuce (use a stay suture to ensure proper alignment). Suture the skin around the preputial orifice using #3 non‐absorbable sutures with a cruciate or horizontal mattress pattern (Figure 21.6) [1]. Close the subcutaneous
