Key Points

  • In that location is truth to the phrase "breed similar rabbits".
  • Male rabbits are also known equally "bucks".
  • Female rabbits are besides known as "does".
  • The doe is brought to the cadet when breeding rabbits.
  • Rabbits have a relatively curt gestation menstruum.
  • Parturition in the rabbit is amend known as "kindling".
  • The newborn rabbit or "kit" is altricial.
  • Rabbit milk is extremely rich.
  • Weanling rabbits are vulnerable to affliction.
  • Juvenile rabbits reach puberty just after they undergo a maximal rate of growth.
  • Sexual beliefs oftentimes manifests as territoriality.
  • Endometrial adenocarcinoma is the nearly mutual neoplasia of female person rabbits.

Introduction

Fifty-fifty in the neutered pet, rabbits draw very piddling distinction between sexual beliefs and social behavior (Harriman 1995). Normal deportment like territoriality, attention-seeking behaviors like honking and circling, and nesting beliefs such as digging and chewing, are all intimately tied to the instinctive drive to reproduce.

If you are reading this article equally function of the Basic Rabbit Care Instruction Module, please go to the sections on male rabbits, female rabbits, newborn rabbit, and rabbit milk. Then accept the brief quiz to test your noesis.

"Breed like rabbits"

The prolific nature of the rabbit has linked them with fertility and the cycle of life and death since ancient times. In fact the thought of the Easter bunny probably arose from the medieval conventionalities that rabbits, as a creator of life, ushered in the dawn (Fig 1) (Mayer 2003).

Rabbits have been associated with fertility and the cycle of life since ancient times.

Effigy ane. Rabbits have been associated with fertility and the cycle of life since ancient times. Photo credit: Elliott Brown via Flickr Creative Commons. Click paradigm to enlarge.

One female rabbit can potentially deliver up to threescore young per year. Because of this fecundity, early explorers carried rabbits every bit a food source and rabbits were fifty-fifty released on remote islands. Unfortunately the absence of predators allowed rabbit populations to rapidly reach pest numbers on some islands similar New Zealand (O'Malley 2005).

Male rabbits

The head and torso of the intact, developed, male person rabbit is generally more than thickset than the doe (Richardson 2000). The penile sheath is cylindrical and the penis tin be hands extruded in rabbits over 2 months of historic period. The scrotal sacs sit craniolateral to the penis (Fig 2). The scrotum is oblong and partially hairless, and the testicles are relatively big with prominent epididymal fat pads (O'Malley 2005).

Figure 2. The oblong, partially hairless scrotal sacs sit craniolateral to the cylindrical penis

Figure ii. The ellipsoidal, partially hairless scrotal sacs sit craniolateral to the cylindrical penis. Photo credit: Dr. Matt Rosenbaum. Click image to enlarge.

The testicles descend former between 10 to 14 weeks of age. The first appearance can vary with the private, the brood, and environmental temperature. The adult rabbit can retract the testes back up into the abdomen through the open inguinal band when stressed or to regulate testicular temperature. Testes descend further on hot days and are brought closer to the torso on cool days. This phenomenon can be distinguished from a true cryptorchid male person past the absence of scrotal sac(s) (O'Malley 2005, Richardson 2000).

Prior to castration of the male rabbit, acme of the hindquarters or gentle pressure level on the caudal abdomen volition crusade testicles to autumn dorsum into the scrotum. A closed castration technique is preferred to minimize the take a chance of post-operative inguinal hernia. If an open surgical technique is performed, the large, superficial inguinal band should be closed.

Female person rabbits

Adult females, particularly medium and large breed does, oftentimes develop a dewlap or fold of skin beneath the chin. Older does tend to be larger than bucks of the same breed (Richardson 2000).

The ovaries are elongated, and are located relatively caudal in the rabbit. The oviducts are very long and coiled. The duplex uterus consists of two separate uterine horns separated forth its length. At that place is no uterine body. The mesometrium is a site of pregnant fat storage in the rabbit, proportionally much greater than in other companion animals. The two uterine horns communicate with two cervices, which bring together to form a common vagina (O'Malley 2005). The rabbit vagina is relatively long and saccular (Vella 2012). The urethra enters the dorsal wall of the vagina; the clitoris sits on the ventral surface. The vulva appears triangular with a slit-like opening, and the advent of this slit is used to distinguish juvenile females from juvenile male person rabbits.

If the urinary float is expressed while the rabbit is in dorsal recumbency, the relatively flaccid vagina tin potentially make full with urine. To minimize the risk of contamination during ovariohysterectomy, the bladder is expressed later the patient is anesthetized only earlier the fauna is placed on its back (Jenkins 2012). The suspensory ligaments are relatively long, making exteriorization of the uterus relatively easy, however the large amount of fat in the wide ligament notwithstanding makes rabbit spays relatively challenging procedures, even in young does. The double cervices are not routinely removed during ovariohysterectomy, however removal is indicated for patients with cervicitis, neoplasia, or endometriosis (Jenkins 2012, O'Malley 2005).

The female person rabbit is an induced ovulator. In that location is no regular estrous cycle, instead ovulation occurs after mating. If coitus does not occur, the doe will vary in receptivity as ovarian follicles regress and new follicles mature. Periods of receptivity last anywhere from v to 14 days and are followed past one to 2 days in which the doe volition pass up to mate. This wheel repeats until conception occurs, although ovarian activity decreases as photoperiod decreases during the tardily summer to wintertime months (Vella 2012, Klaphake 2012, O'Malley 2005).

Vaginal smear cytology is not useful for identification of doe receptivity (O'Malley 2005), however the appearance of the vulva can provide a helpful clue. When the doe is receptive, the vulva is more swollen and is often a pink-regal or reddish-royal color (Klaphake 2012, O'Malley 2005). During anestrus the vulva appears narrow and pale (O'Malley 2005).

Breeding rabbits

Both male and female rabbits tin can be quite territorial, and mating is all-time accomplished if the doe is placed in the buck'south enclosure or if the pair are introduced in neutral territory (Trophy 2006, Richardson 2000).

Upon introduction, the buck follows the doe effectually, softly bustling while sniffing and licking her for approximately 30 seconds (Vella 2012, Bays 2006). He may also spray the female with urine (Bays 2006). The receptive female person will hop effectually in circles or flatten to the floor (Trophy 2006). Lordosis is observed when pressure is practical to her dorsum (Bays 2006), while the non-receptive doe will run away from the buck, and if cornered she may vocalize or fifty-fifty bite. Active mating begins when the cadet grasps the female by the nape with his teeth. He and then mounts the female rabbit, thrusting vigorously until ejaculation occurs relatively chop-chop. Subsequently the male emits a sharp weep or squeak, before falling onto his back or side while the doe either runs away or begins to bite and kick the male person (Video one)(Bays 2006, Richardson 2000).

Video ane. Rabbit breeding is a brief affair

Ovulation occurs ten to 13 hours later on mating (Vella 2012, O' Malley 2005, Richardson 2000). Although a single mating is oft sufficient stimulus to stimulate ovulation, breeders often let mating to occur several times over a 30-minute period before returning the doe to her enclosure. Despite her fecundity, the doe should have no more than than three litters in one year (Richardson 2000). Reproductive life varies with the breed, even so bucks are typically bred for five to 6 years and does for approximately 3 years (Vella 3012).

Gestation

When compared to hares with their 40 to l day pregnancy, rabbits take a relatively brusque gestation period averaging 31 days. Gestation can range from 28 to 35 days (Vella 2012, Bays 2006, O'Malley 2005), still the risk of stillbirth increases by Day 32 (O'Malley 2005). Litter size ranges from four to 12 kits (Vella 2012, Trophy 2006). Small breed rabbits tend to produce smaller litters that are born after a relatively long gestation period (Vella 2012). Larger litters are generally born after a shorter gestation period (O'Malley 2005). The fetus is palpable past Day 12 to 14 (Richardson 2000).

Despite their high fertility rates, rabbits tend to suffer from a loftier incidence of embryonic bloodshed. There are many potential reasons for this trouble including infection, heredity, trauma, drug utilize, poor nutrition, besides as social or environmental stress. Fetal death and resorption is most probable to occur in subordinate does (Vella 2012, Klaphake 2012). The fetus is also at increased risk on Day 13, when placentation changes from yolk sac to hemochorial, and on Twenty-four hours 21 when there is a temporary reduction in blood flow as the fetus changes in shape and size (Klaphake 2012, O'Malley 2005).

Parturition

The doe begins to nest several days to a few hours before parturition. Pilus epilates more hands equally estrogen levels rise and progesterone levels fall, and the doe plucks hair from her abdomen, sides, and dewlap. She then uses the fur to line her nest of hay and straw (Fig iii) (Vella 2012, O'Malley 2005).

The doe interweaves plucked hairs with hay and straw to create her nest.

Figure 3. The doe interweaves plucked hairs with hay and straw to create her nest. Photo credit: Andre Mouraux via Flickr Artistic Commons. Click image to overstate.

Kindling usually occurs during the early morning hours and normally takes about 30 minutes (Vella 2012). The doe begins a fertile postpartum heat inside 24 hours of kindling, however her receptiveness decreases once lactation begins and this lack of interest in breeding continues until after weaning (O'Malley 2005).

Newborn rabbit

Unlike the precocial young of hares, rabbits deliver altricial young that usually counterbalance 40 to 50 grams at nascence (O'Malley 2005, Harkness 1995). The kit is born hairless, with sealed eyelids and ear canals. Anogenital stimulation is required for emptying of feces and urine (Table i) (Bays 2006).

Table i. Developmental stages of the rabbit (Oryctolagus cuniculus) (Bautista 2013, Bays 2006, Richardson 2000)
Day Developmental stage
7 Fur begins to grow
10 Eyes open
12 Ears open

Despite their relatively helpless land, the immature are non brooded by the female parent (Bautista 2013, Bays 2006). Brown fat levels are highest during the first 2 weeks of life. Brown fat produces rut or "not-shivering thermogenesis" because of its all-encompassing capillary network and its reserves are unaffected by the brute's nutritional state (O'Malley 2005).

Until fur begins to grow in at Day x, kits also depend heavily on the warmth and insulation provided by littermates (Bautista 2013, Bays 2006, Hull 1982). Central litter positions are associated with higher body temperature, college milk intake, heavier body weights, and faster growth rates (Bautista 2013), however behavioral differences have also been identified based on litter position during the first calendar week of life. Developed animals that occupied the periphery showed an "enhanced survival instinct" being "more proactive" than "intermediate" or "central" littermates (Reyes-Meza 2011).

Kits rely heavily on their sense of olfactory property at nascency. The female parent is recognized by the smell of her carrion, and suckling is stimulated by a pheromone secreted past a gland nigh the nipple (Vella 2012, O'Malley 2005). Does also odour mark their kits, and females will pursue and even kill kits from other colonies. Successful cross-fostering of neonatal domestic rabbits requires camouflaging the new kit'south smell by rubbing the newcomer in nest bedding and/or placing the kit on the bottom of the litter pile (Bays 2006).

Rabbit milk

Rabbits usually possess 8 mammary glands that extend over their thoracic and inguinal region. Only the doe has nipples. She may possess every bit many every bit 10 nipples, and the presence of accessory nipples is favored by rabbit breeders (Vella 2012, O'Malley 2005).

Rabbit milk is very rich, so rich in fact that the doe needs simply nurse her immature in one case or twice a twenty-four hour period (O'Malley 2005, Cheeke 1987). Rabbit milk is very high in fat (nine%) with unusually low lactose levels (ane%) and very high protein (xiii%) (Table ii) (O'Malley 2005, Cheeke 1987, FAO). Physiologically, lactation is a very enervating fourth dimension for the doe. Water consumption increases 10-fold during lactation every bit does cecotroph consumption (O'Malley 2005).

Table 2. Comparison of rabbit milk and moo-cow milk
Rabbit Cow
Lactose (%) 1 v.0
Poly peptide (%) thirteen 3.3
Fat (%) 9 3.0-4.0

The doe spends approximately 3 to 5 minutes at a time nursing her young (O'Malley 2005, Cheeke 1987). The free-ranging doe then advisedly covers the nest burrow with soil each fourth dimension she leaves (Bays 2006). This "terminate" disguises the nest from predators (Thompson 1994).

The neonatal rabbit tummy has a pH of approximately 5.0 to half dozen.five. A stomach at this pH, full of milk curd, would normally make an ideal substrate for bacterial overgrowth. Fortunately the kit's stomach contains a protective antimicrobial cistron called "milk oil" during the first 3 weeks of life. Milk oil is a mixture of octanoic and decanoic fatty acids and is produced by an enzymatic reaction that occurs when does milk comes into contact with enzymes in the kit's digestive tract. Manus-raised rabbits lack this protective antimicrobial factor making them susceptible to infection (O'Malley 2005, Harkness 1995).

Weaning

Kits begin to go out the nest and eat solid food at approximately Day eighteen-21. Weaning is generally achieved by Mean solar day 42. The doe is usually removed during the weaning process so the immature can remain in a familiar enclosure.

Weaning is a disquisitional time in the rabbit's life when the young are vulnerable to illness. Kits begin to swallow cecotrophs passed past the doe at approximately 2 weeks of age. By the time the protective effect of milk oil ends at 4 to 6 weeks, the gut has not been completely colonized past healthy microbes and tum pH has not reached a mature adult level of 1 to two. "Bad leaner", like coliforms and Clostridia spp., can proliferate causing rapid enterotoxemia, particularly when the rabbit is fed a low fiber, high carbohydrate diet (O'Malley 2005, Cheeke 1987).

Puberty

Until sexually mature, wild rabbits live furtively and often alone. By 3 to four months of age the youngsters may grade pair bonds and accept their place in a colony's social bureaucracy. Since males can outnumber does, male person rabbits sometimes live lonely lives as "satellites" to the colony (Thompson 1994). Bloodshed rates tin exist as high as ninety% during the showtime year of life (Harriman 1995).

Body weight is more important than age in determining sexual maturity. The juvenile rabbit reaches puberty only later on it undergoes a maximal rate of growth; therefore the age of onset for sexual maturity varies with the rabbit breed. Pocket-sized breed rabbits typically develop faster and become sexually mature at an earlier age (Table iii). Does more often than not achieve puberty before bucks (Vella 2012).

Table 3. Typical age of onset of puberty in various rabbit breeds
Small breeds iii.five-5 months
Medium-sized breeds four-vi months
Large breeds 5-eight months

Optimal sperm product occurs 40 to 70 days later puberty is reached (Vella 2012). Male person rabbits should be housed separated from females by at least xvi weeks of age to avert unplanned pregnancies.

Sexual behavior

Negative sexual behaviors, such every bit territoriality and aggression, are most intense at the height of boyhood. Observed behaviors can include chinning, circling, honking or oinking, and mounting and humping. During puberty, both males and females that were previously litter trained may also urinate and defecate exterior of the box to mark their territory (Bays 2012). Nesting behavior, such as frantic digging and chewing, is also commonly observed in does (Bays 2012, Bays 2006). Visit Behavior Nuts: The European Rabbit for additional details on sexual beliefs in the pubescent rabbit.

Fortunately neutering improves the pet quality of house rabbits, and responsible rabbit owners elect to take their pets spayed or neutered. Viable sperm can persist post-castration, and so it is prudent to keep the buck separate from the doe for 4 to 6 weeks to be condom.

Pathology

Uterine adenocarcinoma is the most common neoplasia of the domestic rabbit (Varga 2013, Klaphake 2012, Vinci 2010, Walter 2010). The incidence of uterine tumors is independent of the doe's convenance history (Klaphake 2012). Age is considered the virtually important chance gene for this slowly developing tumor, and the incidence of illness is highest in middle aged to older rabbits (Klaphake 2012, Saito 2002). Uterine adenocarcinoma is nowadays in approximately lx% of females after 4 years of age (Varga 2013); the mean age of affected rabbits at presentation is vi.1 years (Walter 2010).

Early clinical signs of uterine adenocarcinoma tin can include subtle, non-specific signs of illness such as anorexia, and loss of body status. Infertility, vaginal discharge, and hematuria can also be observed (Fig 4). Pale mucous membranes will develop with persistent or heavy hemorrhage (Varga 2013, Walter 2010). As disease advances, boosted findings can include gastrointestinal stasis, swollen, painful mammary glands, and abdominal swelling. Multiple masses may be palpable cranial to the urinary float on concrete exam. Does are sometimes presented for dyspnea secondary to pulmonary metastases or excessive uterine enlargement (Varga 2013).

Hemometra due to adenocarcinoma in a doe

Figure 4. Hemometra due to adenocarcinoma in a doe. Notation the duplex uterus. Photo credit: Uwe Gille via Wikimedia Eatables. Click image to enlarge.

Uterine neoplasia is best managed through prevention. Does not intended for convenance should be spayed early. The owners of intact females should exist educated on the early on signs of disease, and instructed to present the doe regularly for physical exam (Klaphake 2012).

Other pathologic weather condition usually reported in the doe include endometrial hyperplasia, pyometra, endometritis, and pseudopregnancy (Varga 2013, Klaphake 2012, Walter 2010, O'Malley 2005). Pseudopregnancy, also known as pseudocyesis or "faux pregnancy", can occur even in does housed solitary although the most mutual causes include an infertile mating or the presence of a nearby male rabbit (Klaphake 2012, O'Malley 2005). Equally the mature corpus luteum (CL) secretes progesterone, enlargement of the uterus and mammary glands is most pronounced during the first x days. By Mean solar day 16, organs begin to anfractuous. The CL begins to degenerate subsequently Day 18. As progesterone levels autumn, the doe volition pluck fur to make a nest later xviii to 22 days (O'Malley 2005).

Test your knowledge

References

References

Batista A, Castelán F, Pérez-Roldán H, et al. Competition in newborn rabbits for thermally advantageous positions in the litter huddle is associated with private differences in brown fat metabolism. Physiol Behav 118:189-194, 2013.

Bays TB. Behavior of small mammals. . In: Quesenberry KE, Carpenter JW (eds). Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery (third ed). St. Louis: Elsevier Saunders; 2012: 545-549.

Bays TB. Rabbit behavior. In: Bays TB, Lightfoot TL, Mayer J (eds). Exotic Pet Behavior: Birds, Reptiles, and Minor Mammals. St. Louis: WB Saunders; 2006: 1-17.

Cheeke PR. Rabbit Feeding and Nutrition. Orlando: Academic Press; 1987.

To cite this page:

Pollock C. Rabbit Reproduction Nuts. May 15, 2014. LafeberVet website. Available at https://lafeber.com/vet/rabbit-reproduction-basics/