The word neuter refers to the removal of the reproductive organs of either a male or a female of a species, although people frequently refer to the surgery in a female as a spay. The scientific terminology for neutering in the male is castration and in the female is ovariohysterectomy. Let's take a look at the issue of neutering and whether or not it is appropriate for your pet rabbit.
Reasons for Neutering Rabbits
Prevention of Pregnancy
This is the most common reason that rabbits are neutered, particularly if there are both male and female rabbits living together in a household. There are certainly enough rabbits in the world and too many are neglected or abandoned. One should not consider breeding these pets just for fun or education. Be a responsible pet owner and do not breed your pet unless you are well educated on the topic and are prepared to take on all the responsibilities such activity entails.
Prevention of Uterine Cancer
This is the most compelling medical reason to neuter female rabbits. In some rabbit populations the rate of uterine adenocarcinoma (a malignant uterine cancer) can approach 80% of the females. It is believed that the incidence may be related to the rabbit’s genetic makeup. Since we usually don't know the genetic background of most of our rabbits, it is best to have the surgery done as a preventative for this cancer. Uterine adenocarcinoma can spread rapidly to other organs of the body such as the liver, lungs and even the skin and it is not treatable once it metastasizes outside of the uterus. We see many cases of this disease each year and sadly these rabbits could have avoided this problem. Rabbits under two years of age rarely develop this disease so it is best to get your female spayed before this age.
Prevention of other Uterine Disease
Although cancer is the most common disease of the rabbit uterus, we see many cases a year of other uterine disease such as pyometra (infected uterus full of pus), uterine aneurism (uterus full of blood) and endometritis (inflamed uterine lining). Like uterine cancer, these conditions are all more common in female rabbits over two years of age.
Prevention of False Pregnancies
Female rabbits can go into a hormonal state triggered by their ovaries where the body acts as if it is pregnant but there is in fact no pregnancy. Although this is not medically harmful, it can be stressful for the rabbit who goes through all the activities of being pregnant including nest building, milk production and aggressive protection of her territory. This aggression can be taken out on the caretakers and cage mates and can make the pet difficult to handle during this period. Some rabbits experiencing false pregnancy will develop a decreased appetite and have gastrointestinal disturbances as well.
Prevention of Mammary Gland (Breast) Disease
Mammary gland cancer is not common in female rabbits, but when it occurs it can spread rapidly and be difficult to treat. It is preventable if the pet is neutered before two years of age. It is interesting to note that the most common type of mammary cancer is a malignant form called mammary carcinoma and it is almost always associated with uterine cancer. The other common mammary gland disease is mammary dysplasia or cystic mammary glands. This is a benign condition, where the mammary glands fill with a cystic material. It can be uncomfortable to the pet. Neutering a female rabbit before two years of age will prevent both of these diseases.
Prevention of Aggressive Behavior
Both male and female rabbits can display aggressive behavior when they are sexually mature. Many rabbits are sweet and easy to handle as little babies, but when the teenage years hit at around six to twelve months of age...watch out! They can become little Frankensteins almost overnight! They don't want to be touched or picked up and they act like they want to destroy everything in sight. This is their way of learning to protect themselves, their territory and potential future families and to establish their social position in the big wide rabbit world. However, they can often take out their aggression on you or their cage mates. There may be more biting, striking, lunging and chasing. It is best to neuter just before or shortly after sexual maturity to keep this behavior to a minimum.
Prevention of Urine Spraying
Both male and female rabbits can spray urine on vertical surfaces to mark their territory. Intact mature males do this at least 10 times more frequently than females. In addition, the urine from a sexually mature male rabbit can have a strong odor that is unpleasant to many humans. If this behavior is allowed to continue for a long period of time, it may be impossible to completely stop this behavior. Therefore, it is best to nip it in the bud and get the little guys neutered just prior to or shortly after sexual maturity.
Prevention of Testicular Disease
Disease of the testicle is uncommon in the male rabbit, but it can occur. Most commonly we see abscesses (usually the result of bite wounds from other rabbits), hematomas (blood filled areas) and cancer.
Age to Neuter
The best age to neuter either a male or female rabbit is just before or shortly after sexual maturity. Depending on the breed, this time could range from four to six months in the small to medium sized breeds and up to nine months in the giant breeds. We do not recommend neutering rabbits younger than four months of age because the surgery may be more difficult due to the size and position of the reproductive organs. There is no health benefit to neutering earlier than four months of age. However, there is a benefit in females of neutering before two years of age to reduce the incidence of uterine and mammary gland disease.
Your rabbit should be examined by a veterinarian prior to surgery to make sure he is in good condition and ready for neutering. Sexual maturity can be gauged a number of ways including; visualizing testicles in the scrotal sacs, a well developed vulva, a mature body condition, and by behavioral changes such as urine spraying and increased aggression. Your veterinarian may recommend some simple tests prior to surgery, particularly if your pet is older or has had other medical problems. We do not recommend performing routine neutering procedures on obese animals or those with other disease because these rabbits are at higher risk for surgical complications. The weight should be reduced and any disease conditions managed prior to having a major elective surgical procedure performed.
What Happens at Neutering
When a male rabbit is castrated, the testicles are completely removed. There may either be one incision in front of the testicles through which both are removed, or there may be two incisions, one over each scrotal sac. The incisions may be left open which is acceptable if scrotal incisions were made, or closed with suture or surgical glue if the incision was made in front of the scrotal sacs. The scrotal sacs will swell within 24 to 48 hours after surgery but in another seven to ten days the swelling should be gone. The scrotal sacs will eventually shrink to a very small size over time. It is important to note that neutered males should not be put in contact with intact females for at least 3 weeks after neutering. Male rabbits can still have living sperm in ducts within the spermatic cord called the vas deferens, which cannot be removed during surgery. The sperm in these ducts can live for two weeks. Testosterone blood levels drop slowly after neutering and male rabbits will still try to mate with female rabbits for several weeks after the testicles are removed. After three weeks the sperm are completely dead. Since the testicles are gone, no new sperm are being produced so it is safe to put a male and female rabbit back together again. However, whenever you put two rabbits together, regardless of the circumstances you must watch closely for signs of aggression. Aggressive rabbits left unattended can cause serious and sometime fatal injuries.
When a female rabbit is neutered, the ovaries, the oviducts, the uterus and often both cervices are removed. Rabbits have a uterus that is made up of two long tubes with an ovary at one end and a cervix at the other. They have two cervices unlike cats, dogs, humans and many other species which only have one. An incision is made just below the umbilicus (belly button) and the uterus and associated structures are gently pulled out from the abdomen through this incision. The blood vessels supplying the uterus and ovaries are tied off with suture material, surgical clips or a laser and the reproductive organs are removed. The incision is sutured with two to three layers of suture material. Since rabbits have incisors that are excellent at cutting through many materials, we find it beneficial to bury the final row of sutures under the skin so they are not accessible. In this way the rabbit has nothing to chew on or pull out. These sutures dissolve eventually over several weeks and there are no external sutures to remove.
Some veterinarians are now advocating the removal of only the ovaries in female rabbits less then 2 years of age. These veterinarians argue that uterine cancer usually occurs after two years of age and the removal of only the ovaries is a shorter and less invasive surgery and thus less stress on the rabbit. This is still a controversial topic because it is difficult to know at exactly what time uterine cancer may start at the microscopic level. Exotic animal veterinarians will be looking carefully over the next few years at these ovariectomy cases to see if uterine cancer was prevented during the life of the rabbit. Consult with your veterinarian on this topic so you can make an informed decision. However, if you have acquired an adult rabbit and you do not know the exact age of the rabbit (such as when adopting from a rescue), I highly recommend having both the uterus and the ovaries removed to be on the safe side.
Postsurgical Care
It is important after any surgery to check the surgical site at least twice a day for any signs of bleeding, unusual swelling, discharges or opening of the wound. Many rabbits will be off feed for 24 hours after surgery, but this should gradually return to normal over the next two to three days. In addition, some rabbits will have unusual stools for a day or two including soft stools, clumped stools, and irregularly shaped or small stools. If your rabbit is acting very uncomfortable, is extremely lethargic, is not eating at all, is not producing any stools or is unwilling to move, contact your veterinarian immediately. Your veterinarian should prescribe a post-surgical pain medication for one or more days for your pet, which will help ease discomfort and shorten the recovery time. It is usually not necessary to use an antibiotic after a routine neutering. One may be prescribed if the pet had other problems or if there were complications at the time of surgery. After doing literally hundreds of these procedures over the years, we find that the great majority of rabbits return completely to normal within five to seven days, which is a far shorter recovery period then most humans experience!
The long term-benefits of neutering far outweigh the temporary discomfort felt after the surgical procedure.