Two Techniques for Neutering a Degu

www.exoticdvm.com EXOTIC VOLUME 6.6 D V M 27 Bilateral orchiectomy from an abdominal approach is feasible in all small mammal species having an open vaginal process (inguinal canal). This technique also has been described in rabbits. For better comprehension of the proper techniques for neutering rodents, it may be useful to review some anatomical features. Because the inguinal canal of lagomorphs and rodents remains open throughout life, there is not a true scrotum, but rather two separate hemiscrotal sacs. In lagomorphs, they are positioned cranial to the penis; in rodent species, they are caudal to the penis, as they are in other species of placental mammals (except rabbits). The term “canal” is not appropriate for rodents, because it is so wide. Hemiscrotal sacs have anatomic peculiarities among different groups of rodents. Rat-like rodents (rat, mouse, hamster, gerbil) have welldeveloped hemiscrotal sacs. The most common technique for castration in these species is scrotal or prescrotal access, both with an open (uncovered) or closed (covered) technique. Porcupine-like rodents (guinea pig, chinchilla, degu) have less developed hemiscrotal sacs, which are more similar to “diverticula” of the abdominal cavity, but the technique for castration is similar to that of rat-like rodents (see Exotic DVM 6[5]:27-30 for a scrotal technique for neutering chinchillas). Squirrel-like rodents do not have well-developed hemiscrotal sacs because the testicles are located caudally in the inguinal canal or in the abdomen, depending on the season. They could be defined as “functional cryptorchids.” On the basis of these features, castration in prairie dogs (usually done when they are young) is easier when performed with the abdominal approach, because it is easier to locate the testicles (see Exotic DVM 2[5]:1923, 2000). In adult prairie dogs, the prescrotal technique is possible, because under anesthesia it is easy to push the testicles caudally. Being a porcupine-like rodent, degus are different from prairie dogs. The scrotal or prescrotal technique is feasible and recommended. It is accurate to compare this species to a gerbil, which is a rat-like rodent. In all rodent species, it is recommended or mandatory to perform ligation of the vaginal process (inguinal canal) to prevent herniation of fat, seminal vesicles, urinary bladder or bowel. This is more difficult in squirrel-like rodents, since the hemiscrotal sacs are not well developed. Vittorio Capello, DVM Clinica Veterinaria S. Siro Clinica Veterinaria Gran Sasso Milano, Italy [email protected]