Temperature		38–40°C
Heart rate		130–325 beats/min
Respiratory rate		32–60/min
Life span		5–9 yrs
Blood volume		55–65 ml/kg
Food consumption		50 g/kg/day
Water consumption
	General population	50–100 ml/kg/day
	Breeding does	<900 ml/kg/day

Table 176-2 REFERENCE RANGES FOR HEMATOLOGIC VALUES IN RABBITS

Erythrocytes		5.1–7.9 × 10⁶ m³
Hematocrit		33%–50%
Hemoglobin		10.0–17.4 g/dl
Mean corpuscular volume		57.8–66.5 μm³
Mean corpuscular hemoglobin		17.1–23.5pg
Mean corpuscular hemoglobin concentration		29%–37%
Platelets		250–650 × 10³/mm³
Leukocytes		5.2–12.5 × 10³/mm³
	Neutrophils	20%–75%
	Lymphocytes	30%–85%
	Monocytes	1%–4%
	Eosinophils	1%–4%
	Basophils	1%–7%

Table 176-3 REFERENCE RANGES FOR SERUM BIOCHEMICAL VALUES IN RABBITS

Albumin	2.4–4.6 g/dl
Alkaline phosphatase	4–16 U/L
Amylase	166.5–314.5 U/L
Bicarbonate	16–38 mEq/L
Blood urea nitrogen	13–29 mg/dl
Calcium	5.6–12.5 mg/dl
Chloride	92–112 mEq/L
Cholesterol	10–80 mg/dl
Creatinine	0.5–2.5 mg/dl
Globulin	1.5–2.8 g/dl
Glucose	75–155 g/dl
Glutamic-oxaloacetic transaminase	14–113 U/L
Glutamic pyruvate transaminase	48–80 U/L
Lactic dehydrogenase	34–129 U/L
Phosphorus	4.0–6.9 mg/dl
Potassium	3.6–6.9 mEq/L
Serum protein	5.4–8.3 g/dl
Sodium	131–155 mEq/L
Total bilirubin	0.0–0.7 mg/dl
Total lipids	243–390 mg/dl

Table 176-4 REFERENCE RANGES FOR URINALYSIS IN RABBITS

Urine volume
	Large breeds	20–350 ml/kg/day
	Average breeds	130 ml/kg/day
Specific gravity		1.003–1.036
Average pH		8.2
Crystals present		Ammonium magnesium phosphate, calcium carbonate monohydrate, anhydrous calcium carbonate
Casts, epithelial cells, or bacteria present		Absent to rare
Leukocytes or erythrocytes present		Occasional
Albumin present		Occasional in young rabbits

PATIENT MANAGEMENT

Caging

• Cages or hutches can be purchased or constructed. Cages should be large enough to allow free movement. Small breeds, which weigh up to 2 kg, require a minimum of 1.5 ft² of floor space per animal. Large breeds, which weigh 5 kg or more, require at least 5 ft² of floor space per animal. Cages should be at least tall enough to allow the rabbit to stand on its hind limbs and be easy to clean.

• Cages with plastic bottoms and wire tops are easy to clean and are well ventilated. Wire mesh flooring may also be used; however, provide a solid area for the rabbit as wire flooring may predispose rabbits to sore hocks. Use 14-gauge wire with the mesh openings no greater than 1 × 2.5 cm to prevent the rabbit from getting its feet caught.

• Straw or hay bedding should be provided in one area of the cage. Soiled bedding should be cleaned out daily. Because most rabbits are fastidious and prefer to defecate and urinate in one spot, they often can be trained to use a litterbox.

• Rabbits can be housed indoors or outdoors at temperatures ranging from 40°F to 80°F. Rabbits are very susceptible to heat stroke in ambient temperatures above 85°F. If outdoor housing is used, provide ventilation or protection from direct sunlight. In temperatures below 40°F, provide heat or protection from cold.

• Rabbits should be allowed time out of the cage regularly for exercise and socialization. However, they should always be supervised, as they may chew on dangerous objects such as electrical cords and poisonous plants.

Diet

• Free-choice timothy or coastal hay should be provided to maintain the rabbit’s dental and GI health. High-fiber diets are required for proper wearing of the continuously growing teeth and have a protective effect against enteritis. Inadequate fiber in the diet results in cecocolic hypomotility and ultimately changes in cecal microflora.

• A variety of vegetables and fresh, leafy greens such as dandelion greens, cilantro, parsley, and romaine lettuce should be offered as a salad one to two times daily.

• Pelleted diets are balanced and convenient; however most of these are alfalfa based and are low in fiber. Most commercial pellets are nutrient dense (high in protein and digestible carbohydrates) and can predispose rabbits to obesity. High-fiber, timothy-based pellets (Oxbow Pet Products, Murdock, NE; www.oxbowhay.com) are preferable over alfalfa-based pellets.

• The high level of calcium in alfalfa diets may result in hypercalciuria or urinary calculi.

• Rabbits like sweet foods. A limited amount (approximately 2 tablespoons per 2 pounds of body weight) of fruits such as papaya, melon, or berries can be provided as a treat or to entice an anorectic animal to eat.

• Foods high in starches or fat such as seeds, nuts, bread, and corn are not advisable as they can predispose rabbits to obesity and GI disease.

• Fresh water should always be available. Rabbits have a higher water intake than many other mammals. Their daily average water intake is approximately 50-150 ml/kg of body weight. Rabbits fed a large amount of leafy greens will have lower water intake.

Clinical Techniques

Restraint

Key Point

Restrain rabbits gently but firmly for most procedures. Inadequate restraint can result in a spinal fracture in the rabbit if it is allowed to kick with its hind legs. Support the hindquarters when carrying or lifting a rabbit to prevent spinal injuries.

• Carry the rabbit with its head tucked under one arm while supporting the body with your forearm; stabilize the back and rump with the other hand.

• Alternatively, while supporting the back of the rabbit against your body, the forelegs can be grasped between the fingers of one hand while the hind limbs are supported firmly between the fingers of your other hand. This method is effective for examining the ventrum of the patient. (Fig. 176-1)

• When examining a patient on a table, keep the rabbit close to your body and always keep a hand on it to prevent it from jumping off the table (Fig. 176-2).

• An especially nervous or aggressive rabbit may need to be wrapped securely in a towel to prevent injury to itself and to the handler. Some rabbits also calm down if their eyes are covered with a hand or towel.

Figure 176-1 To examine the ventrum and anal area, cradle the rabbit as shown. Be sure to provide support to the hind limbs.

Figure 176-2 Proper method for restraining a rabbit.

Diagnostic Techniques

Venipuncture

Blood can be collected from the jugular, lateral saphenous, cephalic, and lateral ear veins. Rabbit veins are thin and fragile, so small-gauge needles (i.e., 25-gauge or smaller) should be used. To prevent hematoma formation, apply direct pressure to the venipuncture site for several minutes. Pluck or wet down the fur from the site for better visibility of the vein.

• Jugular veins lie superficially in the jugular furrow. Hold the rabbit at the edge of a table with the neck held in extension. This technique can be difficult in females with large dewlaps and should not be done for patients in respiratory distress. If anesthetized, the rabbit can be placed in dorsal recumbency with the neck extended down over a table edge for better visibility of the jugular veins.

• The lateral saphenous vein is the preferred site for obtaining blood samples for routine blood tests. A fairly large volume of blood can be collected from this vein, especially in medium and large-sized rabbits. Have the handler place the rabbit in either lateral or sternal recumbency with the hind end directed towards the edge of the table. Have the handler hold off the saphenous vein by hooking one or more fingers around the back of the back leg proximal to the stifle; encircling and squeezing the proximal thigh too tightly will cause the vein to collapse. Wet down or pluck the fur from the mid-thigh region to better visualize the vein. Apply direct pressure after venipuncture to prevent hematoma formation.

• Cephalic veins can be used to collect small volumes of blood. Place the rabbit in sternal recumbency and encircle the foreleg around the elbow to extend the leg. Use either a tuberculin or insulin syringe to minimize the risk of collapsing the vein with too much negative pressure.

• Plucking the hair over the vein is easier than shaving fine fur.

• The lateral ear vein can be used for blood collection in some large rabbits. Use extreme caution however, as thrombosis of the vein can result in sloughing of the pinnae.

Treatment Techniques

• Subcutaneous administration of fluids is acceptable in non-critical cases and may be the only practical route of fluid administration in small rabbits. Estimate daily maintenance fluid needs at 100 to 150 ml/kg/24 hours.

• Use an indwelling catheter in critical cases.

• Small-gauge catheters (i.e., 24-gauge) can be placed in the cephalic or lateral saphenous vein in most rabbits.

• Jugular catheters can be difficult to insert and may require a cutdown procedure.

• Medications can be administered orally into the lateral cheek pouch. Use liquid or paste preparations when possible because rabbits have a long, narrow oropharynx that makes pill administration difficult.

• Anorectic animals can be syringe fed specialized hand-feeding formulas for herbivores (Critical Care for Herbivores, Oxbow Pet Products, Murdock, NE; www.oxbowhay.com). A gruel made of moistened rabbit pellets can also be used. Vegetable baby foods are low in energy content and fiber and should only be used short term.

• Nasogastric tubes can be placed in medium-to-large rabbits that require long-term nutritional support or that have had extensive oral surgery. The technique that follows is similar to that for placing a tube in a cat.

• With manual restraint, place two to three drops of a topical anesthetic (Ophthaine, Solvay Animal Health, Inc., Princeton, NJ) in the mucosa of one nostril. Wait 5 minutes, and then repeat application.

• Lubricate the tip of a small infant feeding tube (e.g., 5 Fr., Bard-Parker, Becton-Dickenson and Company, Rutherford, NJ) with topical lidocaine (Xylocaine) jelly. Pass the tube medially along the nasal passage to the level of the last rib. The tip of the tube is located in the distal esophagus.

• Secure the free end of the tube to the skin above the nose and eye with a butterfly tape and suture. An Elizabethan collar may be necessary to prevent the rabbit from dislodging the tube.

• Dietary supplements containing Lactobacillus spp. may aid in the treatment of enteritis by repopulating the GI tract with healthy bacterial flora, decreasing intestinal or cecal pH, and competing with bacterial pathogens for mucosal attachment sites. Commercial products in paste form are available (e.g., Bene-Bac, Pet-Ag, Inc, Hampshire, IL).

• Commonly used antibiotics are listed in Table 176-5.

Table 176-5 DRUGS COMMONLY USED IN RABBITS

Drug	Dose	Comments
*Antimicrobials/Antifungals*
Benzathine, penicillin G	42,000–84,000 IU/kg q7d × 3 treatments SC	For treatment of Treponema cuniculi
Chloramphenicol	30–50 mg/kg q12h PO	For treatment of Treponema cuniculi
Ciprofloxacin	10–20 mg/kg q12–24h PO	Have a suspension made by a compounding pharmacist for easy administration
Enrofloxacin	5–15 mg/kg q12h PO, SC, IM	Limit subcutaneous and intramuscular administration due to potential tissue necrosis at injection sites
Gentamicin	4 mg/kg q24h IM, IV, SC	Use with caution or avoid use
Griseofulvin	12.5 mg/kgq12h PO	Use with caution or avoid use
Penicillin	40,000–60,000 IU/kg q48hr SC	Use with caution
Tetracycline	50 mg/kg q8–12h PO
Trimethoprim/sulfa	30 mg/kg q12h PO, IM, SC
*Antiparasitics/Insecticides*
Fenbendazole	10–20 mg/kg PO, repeat in 14d
Lime sulfur solution	2.5% dip q7d for 4 weeks	Used in young animals for treatment of mites, fleas, fungal dermatitis
Ivermectin	0.2–0.4 mg/kg q10–14d SC for 2–3 treatments	Effective against ear and fur mites
Piperazine citrate	200 mg/kg; repeat in 2 weeks
Pyrantel pamoate	5–10 mg/kg; repeat in 2 weeks
Pyrethrin products	Topically as directed q7d
Selamectin	6 mg/kg topically
Sulfadimethoxine	50 mg/kg PO first dose, then 25 mg/kg q24h PO for 10–20 days	For treatment of coccidiosis
*Tranquilizers/Premedications*
Acepromazine	0.5–1.0 mg/kg IM/SC
Atipamazole	Give same volume SC as medetomidine	Reversal for medetomidine
Diazepam	1–3 mg/kg IV, IM	Used in combination with ketamine
Glycopyrrolate	0.01–0.02 SC
Ketamine	20–50 mg/kg IM
Ketamine/acepromazine	40 mg/kg (K)/0.5–1.0 mg/kg (A) IM
Ketamine/diazepam	10–15 mg/kg (K)/0.3–0.5 mg/kg (D) IM, IV
Ketamine/medetomidine	0.15–0.35 mg/kg (M) IM/5–20 mg/kg (K) IV later
Ketamine/midazolam	25 mg/kg (K)/≤ 2 mg/kg (M) IM
Medetomidine	0.25 mg/kg IM
Midazolam	1–2 mg/kg IM or slow IV
Propofol	2–15 mg/kg IV
Xylazine	1–5 mg/kg SC, IM
*Analgesics*
Aspirin	10–100 mg/kg q8–24h PO
Buprenorphine	0.01–0.05 mg/kg q6–12h SC, IM, IV
Butorphanol	0.1–1.0 mg/kg q4–6h SC, IM, IV
Carprofen	1.0–2.2 mg/kg q12h PO, SC, IM
Flunixin meglumine	1.1 mg/kg q12–24h SC, IM
Ibuprofen	2.0–7.5 mg/kg; PO q12–24h
Ketoprofen	1 mg/kg q12–24h IM
Morphine	2–5 mg/kg q2–4h SC, IM
Oxymorphone	0.05–0.20 mg/kgq8–12h SC, IM

Tranquilization and Anesthesia

• Injectable tranquilizers are suitable for short diagnostic or surgical procedures. Ketamine (5-10 mg/kg) and medetomidine (Domitor, Pfizer Animal Health, Exton, PA) (0.15-0.18 mg/kg) in combination given IM or IV provides adequate relaxation and sedation.

• Use inhalant anesthesia for long or painful surgical procedures. Clinically, isoflurane and sevoflurane are commonly used. Anesthetic induction and recovery are usually faster with sevoflurane. Gas anesthesia in rabbits can be induced by face mask or in an induction chamber. Premedicate with a combination of ketamine with medetomidine, diazepam, or midazolam as needed, especially if using isoflurane. Buprenorphine and glycopyrrolate can also be given as needed. Gradually increase the concentration of isoflurane over several minutes until a surgical plane of anesthesia is reached. Anesthesia usually is maintained at 0.25% to 2% isoflurane in oxygen. With sevoflurane, use an induction level of 5% to 8%, reducing to 0.5% to 3% for maintenance.

Key Point

Intubation can be difficult because of the long, narrow oropharynx, large incisors, and large fleshy tongue that can obstruct the view of the pharyngeal cavity. Intubation is most successful in large rabbits; consider intubating medium-sized rabbits for long surgical procedures. However, repeated attempts to intubate can damage the larynx, causing soft tissue trauma or laryngospasm that can be fatal after the rabbit is extubated. If laryngeal trauma occurs during intubation attempts, abandon the procedure and use a face mask, or postpone the procedure to another day. Corticosteroids may or may not be helpful in decreasing inflammation of the larynx and tracheal mucosa.

• The following technique can be used to intubate medium to large rabbits.

• Administer ketamine (5-10 mg/kg IM) and medetomidine (0.15-0.35 mg/kg IM) in combination. Supplemental isoflurane may be necessary to further relax the rabbit for intubation.

• Place the rabbit in sternal recumbency. Extend the neck straight up and forward.

• Place the tip of the short, flat-blade laryngoscope blade (i.e., Miller blade), at the base of the tongue. Hook the base of the blade against the top front incisors, and use the blade as a lever to see the glottis. Pass a small endotracheal tube along the blade into the opening of the glottis. Depending on their size, most rabbits require a 2.5- to 5.0-mm endotracheal tube. The glottis cannot be seen while trying to pass the tube.

• Alternatively, the glottis can be visualized with an otoendoscope or endoscopic telescope in a sedated rabbit. The endotracheal tube is passed along the endoscope and inserted as above.

• Use a face mask to maintain anesthesia during short procedures or if intubation attempts are unsuccessful.

• Monitor all rabbits closely during any anesthetic episode. A Doppler, EKG monitor, and pulse oximeter can be used to monitor heart rate and oxygen saturation.

DERMATOLOGIC PROBLEMS

Dermatitis/Alopecia

Etiology

• Mange, fur, and ear mites cause localized or diffuse dermatitis, alopecia, or both. The area involved depends on the type of mite (see “Ear Mites”; “Fur and Mange Mites”).

• Dermatophytosis is associated with alopecia and a scaly dermatitis, particularly around the head and ears (see “Superficial Mycosis”).

• Fur-barbering is common in rabbits on diets deficient in roughage. A high incidence of barbering in does is seen during breeding season; this is probably related to hormonal influences.

• Ptyalism, alopecia, and dermatitis around the mouth are associated with malocclusion.

• Moist dermatitis of the dewlap is common in does during breeding season, especially in warm or humid environments.

• Moist dermatitis with erythema and ulceration of the ventral abdomen and perineal area results from urine scald. Urine scald is associated with urinary incontinence, cystitis, excessive calcium in the urine, uterine adenocarcinoma, or poor management and unclean caging.

• Treponematosis (rabbit syphilis), caused by Treponema paraluiscuniculi causes a scaly dermatitis in the genital area. The nose, lips, and periorbital area are less commonly involved.

Ear Mites (Psoroptes cuniculi)

Treatment

• Ivermectin is effective against ear mites (see Table 176-5). Repeat treatment in 3 weeks. A combination therapy of ivermectin and topical acaricides can be used for severe infestations.

• Because the lesions are usually very painful, and the aural crusts resolve after ivermectin treatment, avoid pulling off the crusts to clean the ears. Ears can be cleaned 1 to 2 weeks after pain subsides and lesions heal.

• Apply an antibiotic cream topically if a secondary bacterial infection is present. Topical application of anti-inflammatory agents may be beneficial once bacterial infection is under control.