Domestic rabbit

A domestic rabbit or domesticated rabbit (Oryctolagus), more commonly known as simply a rabbit, is any of the domesticated varieties and sizes of the European rabbit species. Rabbits were first domesticated in the Middle Ages and are used as sources of food, fur, and wool, as research subjects, and as pets. The male is called a buck and the female is a doe; a young rabbit is a kit or bunny. Also any rabbit that is under 6 months is called a junior any rabbit over 6 months is a senior.

History

Phoenician sailors visiting the coast of Spain c. 12th century BC, mistaking the European rabbit for a species from their homeland (the rock hyrax Procavia capensis), gave it the name i-shepan-ham (land or island of hyraxes). A theory exists that a corruption of this name, used by the Romans, became the Latin name for the peninsula, Hispania – although this theory is somewhat controversial.^[1] In Rome rabbits were raised in large walled colonies.

Selective breeding of rabbits began in the Middle Ages, when they were first domesticated as farm animals. By the 16th century, several new breeds of different colors and sizes were being recorded.

In the 19th century, as animal fancy in general began to emerge, rabbit fanciers began to sponsor rabbit exhibitions and fairs in Western Europe and the United States. Breeds of various domesticated animals were created and modified for the added purpose of exhibition, a departure from the breeds that had been created solely for food, fur, wool, or labor. The rabbit's emergence as a household pet began during the Victorian era.

Domestic rabbits have been popular in the United States since the late 19th century. What became known as the "Belgian Hare Boom", began with the importation of the first Belgian Hares from England in 1888 and soon after the founding of the first rabbit club in America, the American Belgian Hare Association. From 1898 to 1901, many thousands of Belgian Hares were imported to America.^[2] Today, the Belgian Hare is considered one of the rarest breeds with less than 200 in the United States as reported in a recent survey.^[3]

The American Rabbit Breeders Association (ARBA) was founded in 1910 and is the national authority on rabbit raising and rabbit breeds having a uniform Standard of Perfection, registration and judging system. The domestic rabbit continues to be popular as a show animal and pet. Many thousand rabbit shows occur each year and are sanctioned in Canada and the United States by the ARBA. Today, the domesticated rabbit is the third most popular mammalian pet in Britain after dogs and cats.

Rabbits have been, and continue to be, used in laboratory work such as production of antibodies for vaccines and research of human male reproductive system toxicology. The Environmental Health Perspective, published by the National Institute of Health, states, "The rabbit [is] an extremely valuable model for studying the effects of chemicals or other stimuli on the male reproductive system." According to the Humane Society of the United States, rabbits are also used extensively in the study of bronchial asthma, stroke prevention treatments, cystic fibrosis, diabetes, and cancer. Animal rights activists have opposed animal experimentation for non-medical purposes, such as the testing of cosmetic and cleaning products, which has resulted in decreased use of rabbits in these areas.

Terminology

Male rabbits are called bucks; females are called does. An older term for an adult rabbit is coney, while rabbit once referred only to the young animals.^[4] Another term for a young rabbit is bunny, though this term is often applied informally (especially by children) to rabbits generally, especially domestic ones. More recently, the term kit or kitten has been used to refer to a young rabbit. A young hare is called a leveret; this term is sometimes informally applied to a young rabbit as well. A group of rabbits is known as a "colony" or a "nest".^[5]

Biology

Diet

The domestic rabbit's diet depends upon whether it is a pet, a meat, or a fur rabbit. Meat and fur rabbits are fed diets which will improve meat or fur production and allow for the safe delivery of large litters of healthy kits while minimising costs and producing feces which meet waste regulations where appropriate.^[6]

Commercial food pellets are available in most countries in a variety of formulations, and are typically fed to adult rabbits in limited quantities to prevent obesity. Most pellets are based on alfalfa as a protein and fiber source, with other grains being used to complete the carbohydrate requirements. Minerals and vitamins geared toward specific requirements of rabbits are added during production. Many commercial rabbit raisers also feed grass hay, although this can represent a hygiene issue in rabbitries.^[7] Alfalfa hay in particular is recommended for immature rabbits.^[8]

In contrast, a pet rabbit's diet may require fewer calories and energy, while taking advantage of many home-prepared ingredients.^[9]:172 (See § Maintenance, below.)

A diet including too many pellets, root vegetables or sugary fruits can lead to diarrhea, obesity, poor wear on molar teeth and other health problems.^[10] Studies have shown that although a short changeover period is needed, domestic rabbits are highly adaptable to diets produced from locally available forage products in developing countries.^[11]

Fresh water should always be available, either in a water bottle or bowl.^[12]

Digestion

Rabbits are hindgut fermenters and therefore have an enlarged cecum. This allows rabbits to digest, via fermentation, what they otherwise would not be able to metabolically process. Because a rabbit has a sensitive and rather substantial gastrointestinal tract, a rabbit's diet should consist of some amount of fiber. Without a proper diet, gastrointestinal stasis can occur and have detrimental effects on the animal.^[13] It is in the cecum that this fiber is digested.

After a rabbit ingests food, the food travels down the esophagus and through a small valve called the cardia. In rabbits, this valve is very well pronounced and makes the rabbit incapable of vomiting. The food enters the stomach after passing through the cardia. Food then moves to the stomach and small intestine where a majority of nutrient extraction and absorption takes place. Food then passes into the colon and eventually into the cecum. Peristaltic muscle contractions (waves of motion) help to separate fibrous and non-fibrous particles. The non-fibrous particles are then moved backwards up the colon, through the illeo-cecal valve, and into the cecum. Symbiotic bacteria in the cecum help to further digest the non-fibrous particles into a more metabolically manageable substance. After as little as three hours, a soft, fecal "pellet", called a cecotrope, is expelled from the rabbit's anus. The rabbit instinctively eats these grape-like pellets, without chewing, in exchange keeping the mucous coating intact. This coating protects the vitamin- and nutrient-rich bacteria from stomach acid, until it reaches the small intestine, where the nutrients from the cecotrope can be absorbed.^[14][15]

The soft pellets contain a sufficiently large portion of nutrients that are critical to the rabbit's health. This soft fecal matter is rich in vitamin B and other nutrients. The process of coprophagy is important to the stability of a rabbit's digestive health because it is one important way that which a rabbit receives vitamin B in a form that is useful to its digestive wellness.^[16] Occasionally, the rabbit may leave these pellets lying about its cage; this behavior is harmless and usually related to an ample food supply.

When caecal pellets are wet and runny (semi-liquid) and stick to the rabbit and surrounding objects they are called ontermittent soft cecotropes (ISCs). This is different from ordinary diarrhea and is usually caused by a diet too high in carbohydrates or too low in fiber. Soft fruit or salad items such as lettuce, cucumbers and tomatoes are possible causes. Increasing dietary fiber and decreasing carbohydrates should restore the gut flora to normal in the cecum and return gastrointestinal tract motility to normal. This can be avoided by providing a healthy diet of unlimited grass hay as the main part with fibrous green foods such as broccoli and cabbage and limited high fiber/low energy pellets. Note also that there are other more serious but uncommon causes such as cancer, intestinal obstructions and abscesses. ^{[17] [18]}

Reproduction

Ovulation is induced by sexual stimulation. Sexual maturity age for small breeds (Mini Rex, Polish) is 4 to 5 months. For medium breeds such as New Zealand, or Rex, onset is 5 to 6 months, and 6–7 months in large breeds (Flemish Giant, Checkered Giant). Males usually require more time to fully mature, and normally reach adult sperm counts between 6–7 months.

Due to the territorial nature of female rabbits, it is standard practice for the doe to always be brought to the buck's cage. When the doe is brought to the bucks' cage, he quickly mounts her, performs pelvic thrusting culminating in ejaculation, and "flops" off. The whole act may take less than 30 seconds, and is often repeated several times. When he is finished, the buck should then be removed, but many breeders will reintroduce the buck a few hours later to increase the size of the litter.^[19][20]

Rabbits are often spayed (if female) or neutered (male) at the onset of adolescence to prevent unwanted offspring, and for health and behavior benefits. (See § Spaying and neutering, below.)

Milk

Rabbits, like all mammals, produce milk for their young. Females have six to eight nipples. They produce milk for four to five weeks. ^[21] Rabbit milk is fairly high in fat, as a percentage by mass. While most species produce approximately 5% milk fat, rabbits produce 12%. See excerpted table below for comparison of species with the highest and lowest milk fat content.^[22]

Species	Fat	Protein	Lactose	Ash	Total Solids
Seal, gray	53.2	11.2	2.6	0.7	68
Whale	34.8	13.6	1.8	1.6	51
Bear, polar	31	10.2	0.5	1.2	43
Rabbit	12.2	10.4	1.8	2	26
Bison	1.7	4.8	5.7	1.0	13
Horse	1.6	2.7	6.1	0.5	11
Donkey	1.2	1.7	6.9	0.5	10

Genetics

The study of rabbit genetics is mainly due to medical researchers, fanciers, and the fur and meat industries. Each of these groups have differing interests and needs for genetic information. In biomedical research community and pharmaceutical industry, rabbits are used to produce antibodies, test toxicity of consumer products, and as a model organism. Among rabbit fanciers, the fiber/fur industry, the genetics of coat color and hair properties are paramount. The meat industry selects for disease resistance, feed conversion ratio, and reproduction potential.

Linkage maps

Early genetic research focused on linkage distance between various gross phenotypes using linkage analysis. Between 1924 and 1941, the relationship between the c, y, b, du, En, l, r1, r2, A, dw, w, f, and br had been established (phenotype is listed below).

• c -- albino
• y -- yellow fat
• du -- Dutch coloring
• En -- English coloring
• l -- angora
• r1, r2 -- rex genes
• A -- Agouti
• dw -- dwarf gene
• w -- wide intermediate-color band
• f -- furless
• br -- brachydactyly

The distance between these genes is as follows, enumerated by chromosome. The format is gene1—distance—gene2 -- ... ^[23]

1. c -- 14.4 -- y -- 28.4 -- b
2. du -- 1.2 -- EN -- 13.1 -- l
3. r1 -- 17.2 -- r2
4. A -- 14.7 -- dw -- 15.4 -- w
5. f -- 28.3 -- br

The rabbit genome has been sequenced and is publicly available.^[24] The mitochondrial DNA has also been sequenced.^[25]

In 2011, parts of the rabbit genome were re-sequenced in greater depth in order to expose variation within the genome.^[26]

Color genes

There are 10 color gene groups (or loci) in rabbits. They are A, B, C, D, E, En, Du, Si, V, and W. Each locus has dominant and recessive genes. In addition to the loci there are also modifiers, which modify a certain gene. These include the rufus modifiers, color intensifiers, and plus/minus (blanket/spot) modifiers. A rabbit's coat only has two pigments, pheomelanin (yellow) and eumelanin (dark brown). There can also be no pigment, causing an albino or white rabbit.^[27]

Within each group, the genes are listed in order of dominance, with the most dominant gene first. In parenthesis after the description is at least one example of a color that displays this gene.

Note: lower case are recessive and capital letters are dominant

• "A" represents the agouti locus (multiple bands of color on the hair shaft). The genes are:
  • A=agouti ("wild color" or chestnut agouti, opal, chinchilla, etc.)
  • a(t)=tan pattern (otter, tan, silver marten)
  • a=self or non-agouti (black, chocolate)
• "B" represents the brown locus. The genes are:
  • B=black (chestnut agouti, black otter, black)
  • b=brown (chocolate agouti, chocolate otter, chocolate)

• "C" represents the color locus. The genes are:
  • C=full color (black)
  • c(ch3)=dark chinchilla, removes yellow pigmentation (chinchilla, silver marten)
  • c(ch2)=medium (light) chinchilla, Slight reduction in eumelanin creating a more sepia tone in the fur rather than black.
  • c(ch1)=light (pale) chinchilla (sable, sable point, smoke pearl, seal)
  • c(h)=color sensitive expression of color. Warmer parts of body do not express color. Known as himalayan, the body is white with extremities ("points") colored in black, blue, chocolate or lilac, pink eyes
  • c=albino (ruby-eyed white or REW)
• "D" represents the dilution locus. This gene dilutes black to blue and chocolate to lilac.^[28]
  • D=dense color (chestnut agouti, black, chocolate)
  • d=diluted color (opal, blue or lilac)
• "E" represents the extension locus. It works with the 'A' and 'C' loci, and rufus modifiers. When it is recessive, it removes most black pigment. The genes are:
  • E(d)=dominant black
  • E(s)=steel (black removed from tips of fur, which then appear golden or silver)
  • E=normal
  • e(j)=Japanese brindling (harlequin), black and yellow pigment broken into patches over the body. In a broken color pattern this results in Tricolor.
  • e=most black pigment removed (agouti becomes red or orange, self becomes tortoise)

• "En" represents the plus/minus (blanket/spot) color locus. It is incompletely dominant and results in three possible color patterns:
  • EnEn="Charlie" or a lightly marked broken with color on ears, on nose and sparsely on body
  • Enen=Broken rabbit with roughly even distribution of color and white
  • enen=Solid color with no white areas
• "Du" represents the Dutch color pattern, (the front of the face, front part of the body, and rear paws are white, the rest of the rabbit has colored fur). The genes are:
  • Du=absence of Dutch pattern
  • du(d)=Dutch (dark)
  • du(w)=Dutch (white)

• "V" represents the vienna white locus. The genes are:
  • V=normal color
  • Vv=Vienna carrier, carries blue-eyed white gene. May appear as a solid color, with snips of white on nose and/or front paws, or Dutch marked.
  • v=vienna white (blue-eyed white or BEW)
• "Si" represents the silver locus. The genes are:
  • Si=normal color
  • si=silver color (silver, silver fox)
• "W" represents the middle yellow-white band locus and works with the agouti gene. The genes are:
  • W=normal width of yellow band
  • w=doubles yellow band width (Otter becomes Tan, intensified red factors in Thrianta and Belgian Hare)
• "P" represents the OCA type II form of albinism, P is because it is an integral P protein mutation. The genes are:
  • P=normal color
  • p=albinism mutation, removes eumelanin and causes pink eyes. (Will change, for example, a Chestnut Agouti into a Shadow)

Breeds

Numerous different, standardized breeds of domestic rabbit have been developed, with various sizes, temperaments, and care requirements. Mostly of them have historically been bred to be much larger than wild rabbits, though selective breeding has produced a range sizes from "dwarf" to "giant", many of which are kept as food and fur animals as well as pets across the world. The modern, long-haired Angora breed is raised for its long, soft fur, which is often spun, like wool, into yarn. Other breeds are raised for the fur industry, particularly the Rex, which has a smooth, velvet-like coat and comes in a wide variety of colors and sizes. There are 49 rabbit breeds recognized by the American Rabbit Breeders Association in the United States,^[29] and over 50 rabbit breeds recognized by the British Rabbit Council. There are many more breeds of rabbits worldwide.

As with breeds of dogs, rabbit breeds were selectively bred by humans at different times to achieve certain desired characteristics. They have as much color variation between them as do other household pets, and vary in other traits from breed to breed, such as coat length and texture, body shape, ear length and position (many are lop-eared), tail size, etc. Temperaments can vary slightly with breed and gender, as with any animal, and this may include contentment and relaxation versus timidity and fearfulness, alertness, playfulness, and submissiveness versus aggression.

Most genetic defects in the domestic rabbit (such as the Holland Lop breed's tendency to develop dental problems) are due to recessive genes. These genes are carefully tracked by fanciers of the breeds who show these animals; just as dog fanciers carefully check for hip, eye and heart problems, rabbit fanciers extensively follow their own lines to breed out unwanted defects.

As pets

Rabbits have been kept as pets in Western nations since the 19th century. Rabbits bond (albeit slowly) with owners,^[30] can learn to follow simple voice commands and come when called by name,^[31]:166 and are curious and playful. They do not make good pets for small children, as rabbits are fragile and easily injured by rough handling, as well as frequently frightened by loud noises and sudden motions.^[32]

United Kingdom regulations require certain vaccinations for all rabbits (see § Health, below); such mandates are not common in other countries. (See § Vaccinations, below.) The keeping of pet rabbits is banned in the Australian state of Queensland.^[33] Rabbits are especially popular as pets in the United States during the Easter season, due to their association with the holiday. However, animal shelters that accept rabbits often complain that during the weeks and months following Easter, there is a rise in unwanted and neglected rabbits that were bought as Easter "gifts", especially for children.^[34] Similar problems arise in rural areas after county fairs and the like, in jurisdictions in which rabbits are legal prizes in fairground games.

There are many humane societies, animal shelters, and rescue groups that have rabbits available for pet adoption. Fancy rabbit breeds are often purchased from pet stores, private breeders, and fanciers.

House rabbits

Rabbits are increasingly kept as house pets in family homes, in "rabbit-proofed" spaces that do not provide dangerous or valuable things upon which to gnaw.^[35][36] Living indoors shelters a rabbit from outdoor dangers such as predators, weather, vehicles, and pesticides, and thus lengthens their lifespan.^[35] Rabbits are easy to housebreak, by training them to use a cat-style litter box, with low-dust litter or other materials that will not cause health problems if ingested. Those that are not spayed or neutered may begin to engage in territorial marking (which can frustrate efforts to litter-train as well as damage household items) and aggressive behavior.^[37][38][39] (See § Spaying and neutering, below.)

Rabbits are usually compatible with other small animals, including other rabbits, birds, and rodents such as chinchillas and guinea pigs (cavies),^[40] but this may not be advisable^[41] (see § Safety, below). They may also be kept with non-aggressive cats and dogs, after gradual introduction, but are usually supervised with them, as both of these other animals have predatory behaviors that may instinctively lead them to attack rabbits, or simply injure them through overly rough play.^[42][43]

This is less likely when the cat or dog is raised from infancy with a rabbit. Some dog breeds, especially those developed for vermin control or for small-game hunting, are more likely to act aggressively toward rabbits and other small animals.

Keeping a rabbit as a house companion was popularised by Sandy Crook in her 1981 book Your French Lop. In 1983, Crook was a featured lecturer to the 35,000 attendees at the American Family Pet Show in Anaheim, California where she presented her personal experiences of living with her indoor rabbit as evidence of a human–rabbit bond.^[44] Throughout the 1980s it became more common to litter-box train a rabbit and keep it indoors, after the publication of Marinell Harriman's House Rabbit Handbook: How to Live with an Urban Rabbit in 1985. The US-based House Rabbit Society was founded in 1988.^[45]

Maintenance

Rabbits are relatively inexpensive to keep when compared to larger animals, such as horses, or to carnivorous ones such as cats and dogs, but their care can still be moderately costly.^[46] Accommodations can range from a sheltered outdoor hutch (see § Housing, below) to an indoor pen or rabbit-proofed room.^[35][47] Pet rabbits' housing, indoor or outdoor, is often equipped with shelves, ramps, tunnels, toys, and other enrichment items. Some indoor/outdoor pet rabbits, kept inside at night, are given the equivalent of a dog run, or collapsible lawn pen fencing, to use during the day.

A pet rabbit's diet, focused on providing adequate fiber, typically consists of timothy grass or other hay (about 80% of the diet),^[48] a fair quantity of leafy greens and other fresh vegetables (not just carrots, which are sugary),^[49] and a limited amount of commercial pellet fodder.^[50] However, testing to determine if this hay/vegetable/pellet diet meets the animal's requirements for minerals and vitamins have not been conducted to the extent that pellet diets have been researched in commercial rabbitry.^[9]:173–4 Some rabbit welfare organizations and veterinarians recommended that a pet rabbit's diet should model off an approximation of a wild rabbit's natural diet as a foraging animal.^[51][52] Outdoor rabbits are also happy to eat some lawn grass, though it is not a complete diet for them. Small scale farming of rabbits often feeds them largely from kitchen scraps.

Regular brushing of the coat helps to increase sanitation and reduce ingestion of loose fur, and is especially important for the recently developed long-haired breeds. Regular trimming of the claws (sometimes called nails) may be needed if a pet rabbit lives indoors where it cannot dig and naturally wear its claws down. In the middle-sized breeds, the teeth grow approximately 125 mm (5 in) per year for the upper incisors and about 200 mm (8 in) per year for the lower incisors. The teeth in most breeds abrade away against one another, giving them a constantly sharp edge.

Behavioral concerns

As the domestic descendants of wild prey animals, rabbits are alert, timid creatures that startle fairly easily, and many of their behaviors are triggered by the fight-or-flight response to perceived threats. According to the House Rabbit Society, the owner of a pet rabbit can use various behavioral approaches to win the animal's trust,^[39] which can be a long and difficult process.^[30]

A rabbit's body language and posture are key factors to determining temperament. Fearful behavior is often the most difficult to discern, as it can be mistaken for submissive behavior, or even contentedness. When a rabbit is fearful it may be twitchy, attempt to flee, crouch low with its ears pulled back, may have an accelerated pulse, or even produce a high-pitched scream. A rabbit's facial expressions may indicate fear, especially with bulging eyes, and cheek muscles pulled tight. A fearful rabbit will sometimes thump its hind legs; while this is a behavior that evolved to alert other rabbits to a potential threat, solitary rabbits also do it instinctively. Contrarily, rabbits may sometimes seem unusually calm when frightened, but are nevertheless highly stressed (see § Tonic immobility, below).

Rabbits are social animals whose welfare benefits from being housed with other rabbits;^[53] however, house rabbits can be kept singly if enough attention is paid to them by the owner.

Safety

Rabbits have been identified with few zoonotic (animal-to-human transmitted) diseases, and are considered low-risk for people with competent immune systems, but a risk exists of transmission of Escherichia coli (E. coli), Encephalitozoon cuniculi, and various Salmonella bacteria species, particularly for people with compromised immune systems. A rare risk is the deadly bacterial disease tularemia (or "rabbit fever", among other names). There is no vaccine currently available (though one was "on the horizon" as of 2008); instead, good hygiene is the best preventative.^[54]

If a rabbit feels a need to defend itself, it may attempt to kick or scratch the perceived threat with its hind legs after rolling onto its back. This could be dangerous for the rabbit as well as for the perceived threat, as it risks injuring its legs or spine.^[55] Simple improper holding or handling of a pet rabbit can lead to strong kicks by the frightened or uncomfortable animal.^[56] Rabbits are occasionally aggressive,^[39] and may grunt, lunge, and even bite as well as scratch. Usually they do not bite hard enough to break skin. Rabbits become aggressive when they feel threatened or are cornered. Non-neutered rabbits may also act aggressively as part of mating behavior or out of protectiveness of their young. Rabbits are most likely to develop aggressive behaviors at the onset of sexual maturity if not spayed/neutered.^[39]

Rabbits' propensity for chewing on electrical cords can lead to electrocution and fire hazards, so keepers hide cables or cover them with flexible clear tubing if they are within range of their rabbits.

Some sources suggest that it may not be a good idea to keep rabbits in close proximity with rodents. Guinea pigs in particular are susceptible to respiratory disease from bacteria that rabbits carry. Additionally, rabbits may harm small rodents sharing their territory.^[41]

Commercial rabbitry

Meat rabbits

Breeds such as the New Zealand and Californian are frequently utilized for meat in commercial rabbitries. These breeds have efficient metabolisms and grow quickly; they are ready for slaughter by approximately 14 to 16 weeks of age.

Rabbit fryers are rabbits that are between 70 and 90 days of age, and weighing between 3 and 5 lb (1 to 2 kg) live weight. Rabbit roasters are rabbits from 90 days to 6 months of age weighing between 5 and 8 lb (2 to 3.5 kg) live weight. Rabbit stewers are rabbits from 6 months on weighing over 8 lb.

Any type of rabbit can be slaughtered for meat, but those exhibiting the "commercial" body type are most commonly raised for meat purposes. Dark fryers (any other color but albino whites) are sometimes lower in price than albino fryers because of the slightly darker tinge of the fryer (purely pink carcasses are preferred by consumers) and because the hide is harder to remove manually than the white albino fryers.

Wool rabbits

Rabbits such as the Angora, American Fuzzy Lop, and Jersey Wooly produce wool. However, since the American Fuzzy Lop and Jersey Wooly are both dwarf breeds, only the much larger Angora breeds such as the English Angora, Satin Angora, Giant Angora, and French Angoras are used for commercial wool production. Their long fur is sheared, combed, or plucked (gently pulling loose hairs from the body during molting) and then spun into yarn used to make a variety of products. Angora sweaters can be purchased in many clothing stores and is generally mixed with other types of wool. Rabbit wool, called Angora, is 2.5 times warmer than sheep's wool.^[57]

Fur rabbits

All rabbits produce fur. Rabbits such as the Palomino, Satin, Chinchilla rabbit and Rex rabbit are commonly raised for fur. Each breed has unique coloring and fur characteristics. The rabbit is fed a diet especially balanced for fur production and is harvested when the pelts have reached prime condition, at an older age than would be optimal for meat production. Rabbit fur is widely used throughout the world. China imports much of its fur from Scandinavia (80%) and North America (5%) according to the USDA Foreign Agricultural Service GAIN Report CH7607.

Laboratory rabbits

Rabbits have been and continue to be used in laboratory work such as production of antibodies for vaccines and research of human male reproductive system toxicology. In 1972, around 450,000 rabbits were used for experiments in the United States, decreasing to around 240 000 in 2006.^[58] The Environmental Health Perspective, published by the National Institute of Health, states, "The rabbit [is] an extremely valuable model for studying the effects of chemicals or other stimuli on the male reproductive system."^[59] According to the Humane Society of the United States, rabbits are also used extensively in the study of bronchial asthma, stroke prevention treatments, cystic fibrosis, diabetes, and cancer.

The New Zealand White is one of the most commonly used breeds for research and testing.

Animal rights activists generally oppose animal experimentation for all purposes, and rabbits are no exception. The use of rabbits for the Draize test,^[60] which is used for, amongst other things, testing cosmetics on animals, has been cited as an example of cruelty in animal research. Albino rabbits are typically used in the Draize tests because they have less tear flow than other animals, and the lack of eye pigment makes the effects easier to visualize.^[61]

Housing

Rabbits can live outdoors in properly constructed, sheltered hutches, which provide protection from the elements in winter and keep rabbits cool in summer heat. To protect from predators, rabbit hutches are usually situated in a fenced yard, shed, barn, or other enclosed structure, which may also contain a larger pen for exercise.^[47] Rabbits in such an environment can alternatively be allowed to roam the secured area freely, and simply be provided with an adapted doghouse for shelter. A more elaborate setup is an artificial warren.

An appropriate hutch provides clean water at all times, and is at least high enough for the rabbit to stand on its back legs without its head touching the ceiling, and horizontally roomy enough to enable the rabbit to take 4 or 5 hops along its length and/or width. The hutch is shaded or otherwise appropriately cooled in summer. It may be heated in winter (although most rabbits, and especially the larger breeds, can be kept outside, with extra bedding, even into temperatures well below freezing, as long as they have a source of unfrozen water. Cages are grouped and covered to increase ambient temperature. Even newborn rabbits do well in a cold environment if they have sufficient nesting material and many siblings to share body heat with, but should stay with the mother for longer periods of time in the winter for warmth. Below -10 degrees Celsius (15 degrees Fahrenheit), it is necessary to shelter all the animals indoors. Domesticated rabbits are most comfortable in temperatures between 10–21 C (50–70 F), and cannot endure temperatures above 32 C (90 F) very well without assistance, such as deep shade, cooled stones, frozen water bottles, and/or fans.

Housing is cleaned regularly to ensure that no build-up of feces or urine occurs, as this can lead to health problems. Solid rabbit waste can be measured in cubic yards per year. This waste is excellent for gardening and composting, and can be collected for these uses whether the rabbit is housed indoors or outdoors. Rabbit droppings are often put in bins with red worms to create the compost, added to compost bins for enrichment of other compost, or applied directly to a garden as a "cool" fertilizer that will not chemically burn plants.

Exhibition

Conformation shows

Show rabbits are an increasingly popular activity. Showing rabbits helps to improve the vigor and physical behavior of each breed through competitive selection. County fairs are common venues through which rabbits are shown in the United States and many other countries. Rabbit clubs at local to national levels hold many shows each year. On any given weekend one may be able to find a show in most regions of the United States and the United Kingdom. Although only purebred animals are shown, a pedigree is not required to enter a rabbit in show sanctioned by the American Rabbit Breeders Association show but is required to register a rabbit with the ARBA.; a rabbit must be registered in order to receive a Grand Champion certificate.^[62] Children's clubs such as 4-H also include rabbit shows, usually in conjunction with county fairs. The ARBA holds an annual national convention which has as many as 25,000 animals competing form all over the world. The national show moves to a different city each year. The ARBA also sponsors youth programs for families as well as underprivileged rural and inner city children to learn responsible care and breeding of domestic rabbits.

Show jumping

Rabbit show jumping, a form of animal sport between rabbits, began in the 1970s and has since become popular in Europe, particularly Sweden and the United Kingdom. Any rabbit regardless of breed may participate in this kind of competition, as it is based on athletic skill.

Health

Disease is rare when rabbits are raised in sanitary conditions and provided with adequate care. Rabbits have fragile bones, especially in their spines, and need support on the belly or bottom when they are picked up.

Spayed or neutered rabbits kept indoors with proper care may have a lifespan of 8 to 12 years, with mixed-breed rabbits typically living longer than purebred specimens, and dwarf breeds having longer average lifespans than larger breeds.^[63] The world record for longest-lived rabbit is 18 years.^[63]

Rabbits will gnaw on almost anything, including electrical cords (possibly leading to electrocution), potentially poisonous plants, and material like carpet and fabric that may cause life-threatening intestinal blockages, so areas to which they have access need to be rabbit-proofed.^[35][36][64]

Veterinary care

Rabbits visit the vet for routine check ups, vaccination, and when ill or injured. Veterinarians who have experience with rabbits, desirable for regular health checkups, can be difficult to locate. However, most emergency medical situations involving pets require the same treatment regardless of the animal's species.^[64] Some veterinary surgeons have a special interest in rabbits and some have extra qualifications. In the UK, the following postgraduate qualifications demonstrate specialist training in rabbits: Certificate in Zoological Medicine, Diploma in Zoological Medicine and Recognised specialist in Rabbit Medicine and Surgery.^[65]

Some of the conditions that can occur in domestic rabbits include the following: dramatic or sudden loss of appetite, severe depression,^[66] breathing problems,^[67] sudden onset of head tilt, signs of maggot infestation,^[68] not passing stools. Rabbits can also be exposed to poisons, involved in an accident, fall from a height or be exposed to smoke. Other conditions which indicate a need for medical treatment are drooling, unexplained weight loss, diarrhea or fur loss. There are many other symptoms for which a rabbit requires medical aid or veterinary attention.

Routine checkups

Routine check ups usually involve assessment of weight, skin, health and teeth by the owner or a veterinarian. This is essential because a rabbit's health and welfare can be compromised by being overweight or underweight or by having dental problems. Checking the teeth is particularly important part of the examination as back teeth can only be seen with an otoscope. Veterinarians can also give personalized advice on diet and exercise.

Vaccinations

In most jurisdictions, including the United States (except were required by local animal control ordinances), rabbits do not require vaccination. In the United Kingdom, all rabbits are required to be regularly vaccinated against rabbit hemorrhagic disease and myxomatosis.^[69] These vaccinations are usually given annually, two weeks apart. If there is an outbreak of myxomatosis locally, this vaccine can be administered every six months for extra protection.^[70] Myxomatosis immunizations are not available in all countries, including Australia, due to fears that immunity will pass on to feral rabbits. However, they are recommended by some veterinarians as prophylactics, where they are legally available.^[31]:182

Spaying and neutering

Rabbit fancier organizations and veterinarians recommend that pet rabbits be neutered or spayed by a rabbit-experienced veterinarian.^[31]:123[71] Health advantages of neutering and spaying include increased longevity, and for females, a reduced risk of ovarian and uterine cancer and endometritis.^{[31]:195–9[38][63]} Neutering and spaying also reduces territorial marking in males, and aggression toward other rabbits.^[37][38][39] Risks associated with spaying a rabbit include infection of the surgical site, and death from anesthesia.^[72]

Parasitic fungus

Some vets now recommend treating rabbits against the Encephalitozoon cuniculi, a parasitic, microscopic fungus. Some studies have indicated that in the UK over 50% of rabbits may be infected with E. cuniculi. The usual drugs for treatment and prevention of this infection are the benzimidazole anthelmintics, particularly fenbendazole, also used as a deworming agent in other species of animal, and shown to be effective in treating this condition in rabbits. In the UK, it is sold over-the-counter in oral paste form as a nine-day treatment for rabbits under the brand name Panacur Rabbit. Fenbendazole is particularly recommended for rabbits kept in colonies and before mixing new rabbits with each other.^[73] E. cuniculi is the primary cause of "wry neck".

Fly strike

Fly strike is a rare condition which mostly affects rabbits kept in extremely unsanitary conditions and is more likely to occur during summer months. Fly strike happens when flies (particularly the botfly) lay their eggs in the damp or soiled fur or in an open wound of a rabbit. Within 12 hours, the eggs hatch into the larva; stage of the fly, known as maggots. The maggots, initially small and almost invisible to the naked eye, can burrow into the skin of the rabbit and feed on the animal's tissue. Within 3–4 days, the larvae can be large as 15 mm long. In rare cases, if not treated, the rabbit can pass into shock and die. The most susceptible animals are those living in unsanitary housing, older rabbits that do not move much, and those that are unable to clean their bottom areas carefully. Rabbits raised on solid floors are more susceptible than rabbits raised on wire floors. Rabbits exhibiting one or more episodes of diarrhea are often inspected, especially during the summer months.^[74] In 2002, the medicine Rearguard was approved in the United Kingdom for 10-week-per-application prevention of fly strike.

Viral diseases

Rabbits are subject to infection by a variety of viruses.

Myxomatosis is a threat to the health of pet and livestock rabbits. Rabbits caged outdoors in Australia are vulnerable in areas with high numbers of mosquitoes. In Europe, fleas are the carriers of myxomatosis. In some countries, annual vaccinations against myxomatosis are available. In Australia, myxomatosis was intentionally introduced into the feral population of European rabbits (which have become an invasive species) as a means of population control. The Australian government will not allow veterinarians to purchase and use the vaccine that would protect domestic rabbits, for fear that this immunity would be spread into the wild by escaped livestock and pets.^[75] This is also the motivation for the pet-rabbit ban in Queensland.^[33]

Rabbit hemorrhagic disease (RHD), also known as viral hemorrhagic disease (VHD) or rabbit calicivirus disease (RCD),^[76] is caused by a rabbit-specific calicivirus known as RHDV or RCV, discovered in 1983. It is highly infectious, and usually fatal. Outward signs are not obvious and usually include little but a fever and lethargy, until after significant internal organ damage results in labored breathing, squealing, bloody mucus, and eventual coma and death. Internally, the infection causes necrosis of the liver and damages other organs, especially the spleen, kidneys, and small intestine. Vaccines are available (and mandatory) in the UK, but often not available elsewhere as of October 2015.

Like myxomatosis, RHD has been introduced into feral populations intentionally, especially in Australia and (illegally) in New Zealand, to thin their numbers, and it has escaped quarantine in some areas. The disease has killed tens of millions of rabbits in China (unintentionally) and Australia, with other epidemics reported in Bolivia, Mexico, South Korea, and continental Europe. Outbreaks have been successfully controlled in the United States (where it was still occasionally reported as of 2007^[76]) and the UK. Populations in New Zealand have bounced back after developing a genetic immunity, and the disease has no effect on native wild rabbit and hare species in the Americas, which are not closely related to the Old World rabbits.

West Nile virus is another threat to rabbits.^[77] This is a fatal disease, and while vaccines are available, they are not specifically indicated for rabbits. Recourse against the disease includes limiting the number of mosquitoes that are around pet rabbits.

Sore hocks

The formation of open sores on the rabbit's hocks, commonly called "sore hocks", is a problem that commonly afflicts mostly heavy-weight rabbits kept in cages with wire flooring^[78] or soiled solid flooring. The problem is most prevalent in rex-furred rabbits and heavy-weight rabbits (9+ pounds in weight), as well as those with thin foot bristles.

The condition results when, over the course of time, the protective bristle-like fur on the rabbit's hocks thins down. Standing urine or other unsanitary cage conditions can exacerbate the problem by irritating the sensitive skin. The exposed skin in turn can result in tender areas or, in severe cases, open sores, which may then become infected and abscessed if not properly cared for.

Most rabbits can live safely on wire floors with the provision of a resting board or mat. Ultra heavy-weight breeds such as Flemish Giants or Checkered Giants are best raised on solid or partially solid flooring. Alternatively, plastic-floored cages can be used in place of wire floors to provide more comfort.

Respiratory and conjunctival problems

An over-diagnosed ailment amongst rabbits is respiratory infection, known colloquially as "snuffles". Pasteurella, a bacterium, is usually misdiagnosed and this is known to be a factor in the overuse of antibiotics among rabbits.^[79] A runny nose, for instance, can have several causes, among those being high temperature or humidity, extreme stress, environmental pollution (like perfume or incense), or a sinus infection. Options for treating this is removing the pollutant, lowering or raising the temperature accordingly, and medical treatment for sinus infections.^[79] Pasteurella does live naturally in a rabbit's respiratory tract, and it can flourish out of control in some cases. In the rare event that happens, antibiotic treatment is necessary.

Sneezing can be a sign of environmental pollution (such as too much dust) or a food allergy.

Runny eyes and other conjunctival problems can be caused by dental disease or a blockage of the tear duct. Environmental pollution, corneal disease, entropion, distichiasis, or inflammation of the eyes are also causes. This is easy to diagnose as well as treat.^[79]

Wry neck

Inner ear infections, certain parasites, strokes, or other diseases or injuries affecting the brain or inner ear can lead to a condition known as "wry neck" or "head tilt." Although a heavy infestation of ear mites, an ear infection, or a head or neck injury can result in these symptoms, the most common cause of these symptoms is E. cuniculi, a parasite (see § Parasitic fungus, above). This condition can be fatal, due to a disorientation that causes the animal to stop eating and drinking.

Dental problems

Dental disease has several causes, namely genetics, inappropriate diet, injury to the jaw, infection, or cancer.

• Malocclusion: Rabbit teeth are open-rooted and continue to grow throughout their lives. In some rabbits, the teeth are not properly aligned, a condition called malocclusion. Because of the misaligned nature of the rabbit's teeth, there is no normal wear to control the length to which the teeth grow. There are three main causes of malocclusion, most commonly genetic predisposition, injury, or bacterial infection. In the case of congenital malocclusion, treatment usually involves veterinary visits in which the teeth are treated with a dental burr (a procedure called crown reduction or, more commonly, teeth clipping) or, in some cases, permanently removed. In cases of simple malocclusion, a block of wood for the rabbit to chew on can rectify this problem.
• Molar spurs: These are spurs that can dig into the rabbit's tongue and/or cheek causing pain. These can be filed down by an experienced veterinarian with a dental burr.

Signs of dental difficulty include difficulty eating, weight loss and small stools and visibly overgrown teeth. However, there are many other causes of ptyalism, including pain due to other causes.^[80] A visit to an experienced rabbit veterinarian is strongly recommended in the case of a wet chin, or excessive grooming of the mouth area.

Gastrointestinal stasis

Gastrointestinal stasis (GI stasis) is a serious and potentially fatal condition that occurs in some rabbits in which gut motility is severely reduced and possibly completely stopped. When untreated or improperly treated, GI stasis can be fatal in as little as 24 hours.

GI stasis is the condition of food not moving through the gut as quickly as normal. The gut contents may dehydrate and compact into a hard, immobile mass (impacted gut), blocking the digestive tract of the rabbit. Food in an immobile gut may also ferment, causing significant gas buildup and resultant gas pain for the rabbit.

The first noticeable symptom of GI stasis may be that the rabbit suddenly stops eating. Treatment frequently includes intravenous or subcutaneous fluid therapy (rehydration through injection of a balanced electrolyte solution), pain control, possible careful massage to promote gas expulsion and comfort, drugs to promote gut motility, and careful monitoring of all inputs and outputs. The rabbit's diet may also be changed as part of treatment, to include force-feeding to ensure adequate nutrition. Surgery to remove the blockage is not generally recommended and comes with a poor prognosis.^[81]

Some rabbits are more prone to GI stasis than others. The causes of GI stasis are not completely understood, but common contributing factors are thought to include stress, reduced food intake, low fiber in the diet, dehydration and reduction in exercise. Stress factors can include changes in housing, transportation, or medical procedures under anesthesia. As many of these factors may occur together (poor dental structure leading to decreased food intake, followed by a stressful veterinary dental procedure to correct the dental problem) establishing a root cause may be difficult.^[82]

GI stasis is sometimes misdiagnosed as "hair balls" by veterinarians or rabbit keepers not familiar with the condition.^[83][84] While fur is commonly found in the stomach following a fatal case of GI stasis, it is also found in healthy rabbits. Molting and chewing fur can be a predisposing factor in the occurrence of GI stasis, however, the primary cause is the change in motility of the gut.

Tonic immobility

Coping with stress is a key aspect of rabbit behavior, and this can be traced to part of the brain known as ventral tegmental area (VTA). Dopaminergic neurons in this part of the brain release the hormone dopamine, generalized as a "feel-good" hormone. In humans, dopamine is released through a variety of acts, including sexual activity, substance abuse, and even eating chocolate. However, in rabbits, it is released as part of a coping mechanism while in a heightened state of fear or stress, and has a calming effect. Dopamine has also been found in the rabbit's medial prefrontal cortex, the nucleus accumbens, and the amygdala.^[85] Physiological and behavioral responses to human-induced tonic immobility (TI, sometimes termed "trancing" or "playing dead") have been found to be indicative of a fear-motivated stress state, confirming that the promotion of TI to try to increase a bond between rabbits and their owners—thinking the rabbits enjoy it—is misplaced.^[86] However, some researchers conclude that inducing TI in rabbits is appropriate for certain procedures, as it holds less risk than anesthesia.^[86]

Declawing

A rabbit cannot be declawed. Lacking pads on the bottoms of its feet, a rabbit requires its claws for balance. Removing its claws would render it unable to stand.

See also

• Rabbit
• Cuniculture
• House rabbit
• Dwarf rabbit
• Rabbit show jumping

References

Further reading

• Harriman, Marinell (2005) [1985]. House Rabbit Handbook: How to Live with an Urban Rabbit. Alameda, California: Drollery Press. ISBN 978-0-940920-17-0. 

External links

• The American Rabbit Breeders Association – the oldest and largest rabbit specialist organization in the United States
• The Livestock Conservancy – a registry of the rarest breeds of domestic rabbits
• World Rabbit Science Association – an international science organization dedicated to rabbit health research
• The British Rabbit Council – recognized breeds with photographs and more
• MediRabbit – a site dedicated to spreading the knowledge of rabbit medicine and safe medication in rabbits, for the owner and the vet professional
• Rabbit Breeds - directory of ARBA-recognized breeds of rabbit
• RabbitPedia.com - Source for information about rabbit care.
• House Rabbit Society – a US-based educational and advocacy organization for rabbit pet-keepers, founded in 1988
• Domestic rabbit at DMOZ