Management of rabbits for meat, fur, or wool production is quite different from the maintenance of a pet or house rabbit. The American Rabbit Breeders Association (www.arba.net) provides guidance for both production and pet rabbit care. The House Rabbit Society (www.rabbit.org) is another resource regarding pet rabbit care.
Proper handling and restraint is important. Rabbits have powerful hind limbs, which can kick out and lead to broken backs. Rabbits should never be held by the ears; they should be scruffed at the neck and the body firmly supported at the rump. If they are not held properly and securely, fractures or luxations of lumbar vertebrae can easily follow struggling.
Physical Examination and Sample Collection
Most techniques for physical examination suitable for dogs and cats may be applied to rabbits. A thorough oral exam including palpation of the face and bottom of the jaw should be performed to evaluate dental health. An otoscope or a pediatric nasal speculum can assist visualization of the molars. Sex can be determined by depressing the external genitalia to reveal a slit-like vulva in females and penis in males. The testicles descend at 10–12 wk. Normal body temperature is 103.3–104°F. Body temperature <100.4°F or >105°F is cause for concern.
Blood can be collected from the auricular or central ear artery, cephalic vein, lateral saphenous vein, and the jugular vein. The auricular or marginal ear vein provides a site for venous administration or catheterization. The auricular vasculature is sensitive to temperature; having the rabbit warm (or at least having the ear warm) and applying a topical anesthetic cream greatly facilitate these procedures.
Rabbit clinical pathology varies from other domestic animals. The normal neutrophil:lymphocyte ratio is 1:1. The rabbit neutrophil is called a “pseudoeosinophil” or heterophil due to red-staining cytoplasmic granules. Both the heterophil and the granules are smaller than the eosinophil and eosinophil red granules. Rabbit calcium metabolism results in higher normal blood calcium levels and a wider range than other animals, which can lead to erroneous diagnosis of hypercalcemia. Rabbit urine ranges from yellow to brown or reddish. A dipstick can quickly differentiate normal rabbit urinary pigments from hematuria. Traces of glucose and protein are normal in rabbit urine.
Very few products are licensed for use in rabbits, leading to extra-label use of drug therapies approved for use in other species. Particular caution must be applied to the use of antibiotics that suppress normal GI microflora and result in enteric dysbiosis and/or enterotoxemia. This has been called “antibiotic toxicity.” Antibiotics contraindicated in rabbits include clindamycin, lincomycin, erythromycin, ampicillin, amoxicillin/clavulanic acid, and cephalosporins. The flea treatment fipronil is contraindicated in rabbits due to severe toxic reactions in some individuals. Therapeutic treatment may require aggressive nutritional support via syringe feeding, orogastric tube (14 French), nasogastric tube (4–8 French), or pharyngostomy tube (soft esophagostomy tube designed for cats). A gastrotomy tube is less successful than in dogs or cats.
Rabbit breeds of medium size are sexually mature at 4–4.5 mo, giant breeds at 6–9 mo, and small breeds (eg, the Polish Dwarf and Dutch) at 3.5–4 mo of age. The rabbit is an induced ovulator and, contrary to popular belief, has a cycle of mating receptivity; rabbits are receptive to mating ∼14 of every 16 days. The degree of mating receptivity is indicated by the color of the vaginal orifice and by the amount of moisture on the labia. A doe is most receptive when the vagina is red and moist. Does that are not receptive have a whitish pink vaginal color with little or no moisture. Many breeders test mate the doe 10–16 days after breeding, as a means of detecting pregnancy, but this is unreliable. Palpation of the doe's abdomen for “grape-sized” embryos in the uterus is a much better technique for detecting pregnancy. The best time to palpate is 12 days after breeding. Pseudopregnancy is common in rabbits and can follow any induced ovulation, the introduction of a male rabbit in the environment, or other stimuli.
A ratio of 1 buck to 10 does is common practice, but many commercial growers find that 1 buck to 20–25 does is more economical. Bucks can be used daily without decreasing fertility; more frequent use requires periods of rest. The doe should always be taken to the buck's cage for breeding. The breeding program should continue year round. Does that experience long periods of rest between litters tend to become obese and difficult to breed. Does that are constantly in gestation and lactation may become underweight, and their receptivity to the buck and fertility decrease dramatically. If breeding is delayed several weeks and the doe is given full feed, weight is quickly regained.
The gestation period is ∼31–33 days. Does with a small litter (usually ≤ 4) seem to have a longer gestation period than does that produce larger litters. If a doe has not kindled by day 32 of gestation, oxytocin (1–2 IU) should be given to induce parturition; otherwise, a dead litter is almost always delivered sometime after day 34. Occasionally, pregnant does abort or resorb the fetuses due to nutritional deficiencies or disease.
Nest boxes should be added to the cages 28–29 days after breeding. If boxes are added too soon, the does foul the nests with urine and feces. A day or two before kindling, the doe pulls fur from her body and builds a nest in the nest box. The young are born naked, blind, and deaf. They begin to show hair on day 2–3 after birth, and their eyes and ears are open by day 10. Neonatal rabbits are unable to thermoregulate until about day 7. Rebreeding can occur any time after parturition. Some commercial growers use accelerated breeding schedules and rebreed 7–21 days after parturition, while most people raising for show or home use rebreed 35–42 days after parturition.
Most medium-sized female rabbits have 8–10 nipples, and many kindle 12–15 young. If a doe is unable to nurse all the kits effectively, kits may be fostered by removing them from the nest box during the first 3 days and giving them to a doe of about the same age with a smaller litter. If the fostered kits are mixed with the doe's own kits and covered with hair of the doe, they are generally accepted. Moving the larger kits to the new litter instead of the smaller kits increases the chance of success. Does nurse only 1–2 times daily. Kits nurse <3 min. Kits are weaned around 4–5 wk of age.
Rearing Orphaned Infants
Kits can be hand-reared, but mortality is high. They should be kept warm, dry, and quiet. Kitten milk replacer or a formula of ½ cup evaporated milk, ½ cup water, 1 egg yolk, and 1 tbsp corn syrup can be used. Feedings vary from ½ tsp to 2 tbsp, depending on the age of the kits. Kits start eating greens around day 15–18.
Preoperative fasting is not required or recommended. Rabbits cannot vomit. Additionally, rabbit stomachs are never empty, even after prolonged fasting. Premedication with butorphanol or diazepam can reduce stress from preoperative handling. Premedication with atropine may be of little use as many rabbits have an atropinase. Instead, glycopyrrolate may be used to reduce bradycardia and upper airway and salivary secretions (0.01–0.1 mg/kg, IM or SC, or 0.01 mg/kg, IV). Isoflurane is recommended for general anesthesia, but premedication with a combination of an NSAID and an opiate—such as 0.3 mg/kg meloxicam, PO, and 0.4 mg/kg butorphanol, IV—can reduce the minimum alveolar concentration of isoflurane from 2.5% to 2.3%. The long and narrow pharynx and the large tongue make rabbits difficult to intubate, but it is possible with practice. Laryngospasm can be limited by application of lidocaine on the epiglottis.
There are several reported techniques for intubating rabbits. All require selection of the appropriate tube size and length to avoid tracheal injury. A pediatric laryngeal mask, uncuffed Cole, or cuffed Murphy eye type endotracheal tube (ET) can be used, but selecting the appropriate size for the patient (2.0–4.0 mm) is critical. Tracheal injury risk increases with repeated intubation attempts, but ET cuff pressure, prolonged intubation duration, and movement of the ET during mechanical ventilation and animal positioning for anesthesia seem to be more critical due to the vascular anatomy of the rabbit trachea. In the classic blind technique, the rabbit is placed in a sternal position with the head held and the nose pointing at the ceiling. The ET is guided behind the incisors and to the larynx. The operator listens for the sounds of inspiration and expiration and times the advancement of the ET with maximal inspiration. A second technique involves placing the rabbit in lateral recumbency with the head dorsiflexed. The ET is advanced along the hard palate to the back of the throat until condensation can be seen within the lumen of the ET. The condensation is used to judge the cycles of inspiration and expiration, and the ET is advanced at maximal inspiration. Direct visualization of the epiglottis and ET placement can be accomplished using a laryngoscope with a Miller 0 blade, rabbit oral specula, and cheek dilators. Proper ET placement should be confirmed regardless of placement method.
Adequate general anesthesia can be achieved for a short procedure with injectable ketamine (25–50 mg/kg) in combination with a tranquilizer such as xylazine (5–10 mg/kg, IM). The combination of ketamine (35 mg/kg, IV), medetomidine (0.03 mg/kg, IM), and buprenorphine (0.03 mg/kg, IM) has a prolonged duration when compared to ketamine-xylazine alone. Atipamezole (1 mg/kg, IV) can be used as a medetomidine reversal agent when the medetomidine is given IM and not SC.
It is critical to get rabbits eating postoperatively, and analgesic treatment for 1–2 days will help prevent inappetence. A painful rabbit may chatter or grind its teeth while sitting in a hunched position. Analgesic treatment may include opioid drugs such as buprenorphine (0.01–0.05 mg/kg, SC, IM, or IV, bid-tid) or butorphanol (0.05–0.4 mg/kg, SC or IM, bid-tid), or NSAID such as carprofen (1.5 mg/kg, PO or SC, bid), flunixin (0.5–2 mg/kg, PO, deep IM, or IV, sid for no more than 3 days), or meloxicam (0.3 mg/kg, PO, tid or 1.5 mg/kg, SC or PO, sid). Tramadol used at 11 mg/kg, PO, causes no ill effects and the drug has been reported empirically effective in rabbits. Fentanyl patches are effective, but rabbit fur grows so quickly that contact is difficult to maintain. Electroacupuncture and acupressure may be helpful in rabbits.
Postoperative supportive care is critical to a successful surgical outcome. Hay and water should be offered as soon as possible following surgery. Alfalfa hay can be used to improve appetite. Banana is favored as a treat by many rabbits. Hand feeding is necessary if the rabbit does not eat on its own. Critical Care (Oxbow Pet Products) is a recovery diet that can be made into a gruel (10–15 mL /kg, PO, tid-qid).
Castration can reduce aggressive behavior and is suggested for house rabbits and group-housed rabbits. It has no advantage for meat-type rabbits. The scrotums are lateral and anterior to the penis, as in marsupials and not as in most other placental mammals. Castration is performed using a closed technique or by an open technique with closure of the large superficial inguinal ring to prevent herniation.
Female pet rabbits should be spayed due to the risk of uterine cancer. Rabbits have 2 uterine horns connected to the vagina by separate cervices. The oviduct loops around and is much longer than in cats or dogs. Older or multiparous rabbits will have a more complicated spay due to the large amount of fat in the mesometrium. Postoperative adhesions are a common complication, which may be reduced by calcium-blocker treatment (verapamil, 200 μg/kg, SC, tid for 3 days).
When gastrotomies are performed to remove a hairball, the stomach is elevated by stay sutures through a cranial celiotomy incision. An incision is made through the greater curvature of the stomach. The hairball is often so firm and well packed that it may be removed in one piece. It is important to remove fur from the pyloric sphincter and to examine the stomach lining for abnormalities. A fine absorbable monofilament suture is preferred over gut suture due to the acidic environment of the rabbit stomach. Sutures should incorporate, but not penetrate, the gastric mucosa. Pre- and postsurgical care should include fluids and antibiotic therapy. Animals remain anorectic and force feeding is typically required.
Rabbits will chew out skin sutures; therefore, skin closure should be performed with a 4-0 absorbable synthetic suture with a cuticular-cuticular pattern. Tissue glue may be added to finish this closure. Rabbits tolerate staples.
Rabbits may jump or scream when the traditional overdose of barbiturate is given in the marginal ear vein. Sedation with ketamine (50 mg/kg), alone or in combination with a tranquilizer such as acepromazine or xylazine, is recommended prior to administration of the barbiturate. As a further precaution, euthanasia solution may be diluted 1:1 with saline to prevent a negative reaction.
Other Management Techniques
Toenails on the rear limbs may severely scratch unprotected arms of handlers. Nails should be trimmed every 1–2 mo. Declawing is not recommended, but some rabbits tolerate application of adhesive nail caps.
Some breeders tattoo or place ear tags on their rabbits for identification purposes. For show purposes, the right ear is reserved for registration marks applied by registrars of the American Rabbit Breeders Association. A tag placed in the anterior cartilaginous part of the ear, nearer to the head, is less likely to be pulled out.
Last full review/revision July 2011 by Diane McClure, DVM, PhD, DACLAM