testicle
The left and right testicles of male rabbits are oval, which are organs that produce sperm and secrete androgen. Its position and size change with age. The testicles of young rabbits are located in the abdominal cavity and generally move down to the scrotum through the inguinal canal after 3 months. However, because the inguinal canal of the rabbit is short and wide, and it is not closed for life, the testis can freely move back to the abdominal cavity through the inguinal canal. Therefore, when examining the testicles of adult male rabbits, we can only let the male rabbits squat on the table in a normal posture or twist the rabbit's head and neck and lift them, and touch the testicles with their hands to check whether they are developing normally. Epididymis is the place where sperm mature and store. The rabbit's epididymis is well developed and consists of three parts: epididymal head, epididymal body and epididymal tail. Sperm has post-ripening effect when passing through epididymis to enhance its vitality.
The vas deferens is an extension of the epididymis. Its muscular layer is developed and its contractility is strong during mating. It can discharge sperm from the tail of epididymis to the genitourinary tract and shoot it out of the body.
Sex accessory gland
It mainly includes seminal vesicle and seminal vesicle gland, prostate, paraprostate and urethral ball gland. The gonadal fluid secreted by them mainly constitutes semen, which provides nutrition for sperm and dilutes viscous semen from epididymis, which is beneficial to sperm operation. During natural mating, the secretion of accessory gonads can also condense in the vagina of the female rabbit to form a vaginal suppository to prevent the outflow of semen.
penis
It is the organ for male rabbits to mate, ejaculate and urinate. It is mainly composed of cavernous body, which contracts in the foreskin when it is calm, and erects and extends out of the foreskin when mating. The front end of the rabbit penis is free and slightly curved, and there is no obvious enlarged glans during mating.
scrotum
The male rabbit has a pair of scrotum, whose main function is to contain and protect the testis, regulate the temperature of the testis and ensure that the testis can produce normal sperm.
Female rabbit's reproductive organs
The reproductive organs of female rabbits mainly include ovary, fallopian tube, uterus, vagina and external genitalia.
Ovary: The female rabbit has two ovaries, which are oval and reddish and located on the body wall behind the kidney. Its main function is to produce eggs and secrete estrogen.
Fallopian tube: it is an organ that transports eggs and fertilizes them.
Uterus: It is the organ for the growth and development of embryos. Rabbit palace belongs to the type of double uterus, that is, it has two uterine bodies, two uterine horns and two cervix, both of which are independently opened at the front of vagina.
Vagina: It is the mating organ of the female rabbit, and it is also the channel for fetal production and urine excretion.
External genitalia: or vulva, including vulva, labia and clitoris. The opening at the end of the vagina is called the vulva, the protrusions on both sides of the vulva are called the labia, and there is a small protrusion at the junction of the two labia called the clitoris.
Reproductive physiology of rabbits
Sexual maturity and first mating age
When rabbits reach a certain age, their sexual organs mature. Male rabbit's testis can produce mature sperm, female rabbit's ovary can produce mature eggs, and show sexual behaviors such as starting love, and mating can conceive, which is called rabbit's sexual maturity. The age of reaching sexual maturity varies with species, sex, individual, nutritional level and genetic factors. Generally, small rabbits are 3 ~ 4 months old, medium rabbits are 4 ~ 5 months old, and large rabbits reach sexual maturity at 5 ~ 6 months old.
When the rabbit reaches sexual maturity, it is not appropriate to breed immediately, because at this time, all parts of the rabbit's body are still in the development stage and have not yet reached physiological maturity. If you breed too early, it will not only affect your own development and cause premature aging, but also have a low pregnancy rate, weak offspring and high mortality. Of course, the age of first mating should not be too old, especially for male rabbits. Mating too late will reduce the litter size of the female rabbit in her life, and make the male rabbit lose sexual desire and reproductive value. Under better feeding and management conditions, the suitable first mating months are: 4-5 months for small varieties, 5-6 months for medium varieties and 7-8 months for large varieties. In production, the first mating time can also be determined by weight, that is, when it reaches about 80% of the adult weight of the variety.
Estrus and estrus cycle
After the female rabbit matures sexually, the estrogen produced by mature follicles in the ovary acts on the sexual activity center of the brain, causing a series of physiological changes in the reproductive tract of the female rabbit, and periodic sexual activity (excitement) occurs, which is called estrus.
The estrus of female rabbits is mainly manifested as: excitement and anxiety, running back and forth in the cage, tapping the bottom plate of the cage with her hind feet from time to time, and making a sound to express courtship. Some female rabbits have poor appetite and often rub their jaws on the trough or other appliances, commonly known as "noisy circles". The vulva of estrus female rabbits will be red and swollen, and the color will change from pink to bright red and then to purple. However, some female rabbits, especially colored rabbits, have no obvious color change in vulva, only edema, increased glandular secretion and other watery and moist phenomena. When the male rabbit climbs up the crotch, the female rabbit in estrus first evades a few steps, then lies down and raises her tail to cater to the mating of the male rabbit. Pubic hydrops and swelling are the main signs of estrus.
Rabbits have the property of stimulating ovulation. Different from other domestic animals, their estrus has an accurate periodicity and a wide range of changes, generally 7 ~ 15 days, and the duration of estrus is generally 3 ~ 5 days. The most suitable time for reproduction is when the genitals are red, just as the proverb says, "powder is early, purple is late, and red is positive." If the female rabbit has no obvious redness and swelling, it is suitable for breeding in the genitals, especially when it is wet.
Pregnancy and pregnancy
After mating, the fertilized egg gradually develops into a fetus in the uterus of the mother rabbit until delivery. This process is called pregnancy, and the whole period of completing this development process is called pregnancy. The gestation period of rabbits is generally 30 ~ 3 1 day, ranging from 28 to 34 days. The length of pregnancy varies with breed, age, number of fetuses, nutritional level and environment. The gestation period of a large variety is longer than that of a small variety, the gestation period of an old rabbit is longer than that of a young rabbit, the gestation period of a few fetuses is longer than that of a large variety, and the gestation period of a female rabbit with good nutritional status is longer than that of a poor female rabbit. Female rabbits in labor, especially those with strong motherhood, have poor appetite before labor, even refuse to eat, and their breasts are swollen and can express milk. The vulva is swollen with blood, and the mucosa is flushed and moist, similar to estrus; A few hours or even 1 ~ 2 days before delivery, some female rabbits (with strong maternal instinct) began to pull weeds and pluck their hair to build nests. However, a few primiparous female rabbits or individuals with weak maternal instinct have no obvious prenatal symptoms.
transmit
The physiological process that the fetus matures and is excreted from the mother is called delivery. The parturition of female rabbits mostly occurs around dawn to 10 am; Generally, it only takes 20 to 30 minutes, and a few people need about 1 hour to complete the calving process. Generally, female rabbits do not need artificial care when giving birth. After the fetus is born, the mother rabbit will eat the placenta, break the umbilical cord and lick the blood and mucus of the young rabbit. Due to physical exertion after delivery, it is easy to feel thirsty. It is necessary to provide clean drinking water in time to prevent the mother rabbit from eating by mistake.
Breeding and utilization years
The reproductive ability of rabbits is in a vigorous period when they are 1-2 years old, and gradually decreases with age after 2 years old. Therefore, breeding rabbits have a suitable service life, generally 2 ~ 3 years, which can be appropriately extended or shortened depending on the quality of feeding management and the physical condition of breeding rabbits.
Feeding method of rabbits
There are three main breeding methods of rabbits, namely natural breeding, artificial assisted breeding and artificial insemination.
natural mating
Mating a female rabbit in estrus with a male rabbit is called mating. The advantages of natural mating are simple mating method, labor saving and high mating rate.
Specific operation method: Put the oestrus female rabbits confirmed to be suitable for breeding into the male rabbit cage for observation, and confirm whether the mating between male and female rabbits is successful. As soon as the female rabbit entered the male rabbit cage, the male rabbit immediately began to chase and climb over the female rabbit. When the female rabbit crouches down to accept the climbing of the male rabbit and raises its tail to cater to the mating of the male rabbit, it means that the penis of the male rabbit has been inserted into the vagina of the female rabbit for ejaculation, and when its hind leg quickly leaves the bottom of the cage and clings to the hind leg of the female rabbit, the mating is successful. Then the male rabbit slips off the female rabbit and leaves the female rabbit, indicating that mating is complete. At this time, the mother rabbit should be lifted immediately and patted on her hips with her hands to make her curl up in shock to prevent the semen from overflowing in the vagina. Then put the mother rabbit back in the original cage and make a breeding record.
Artificial assisted breeding
It means that when some estrus female rabbits are unwilling to automatically lift their tails to accept the male rabbits' climbing mating (refusing to mate), they are forced to lift their tails artificially, forcing the female rabbits to cater to the male rabbits' climbing until the mating process is completed, which is called artificial assisted mating. Using artificial assisted breeding can improve the conception rate of first-mated female rabbits and female rabbits with weak estrus, and improve the reproductive efficiency of rabbits.
The specific operation steps are as follows: the breeder holds the ear and neck skin of the oestrus female rabbit with one hand to stabilize the female rabbit, and the other hand reaches under the female rabbit's crotch to lift her hips, pokes her tail with the middle finger to expose the vulva, pinches the vulva with the index finger and thumb, puts the penis between the male rabbit's crotch to directly feel the male rabbit's penis inserted into the female rabbit's vagina, and puts the female rabbit back into its original cage after mating. For the convenience of operation, the tail of the female rabbit can be tied with a string, pulled to the head and neck along the back neckline, and then the hip of the female rabbit is lifted and sent to the crotch of the male rabbit to complete the breeding work.
If the female rabbit does not accept mating during estrus, but should mate, compulsory auxiliary mating can be adopted; That is, the breeder holds the ear and neck skin of the female rabbit with one hand, and the other hand reaches under the abdomen of the female rabbit, lifts her buttocks, fixes her tail with the index finger and middle finger, exposes the vulva, and lets the male rabbit climb up the crotch to mate. Or tie the tail of the female rabbit with a string, pull it to the front of her head along the back neckline, grab the string and the neck skin of the rabbit with one hand, and lift her hips slightly from the lower abdomen of the female rabbit with the other hand to help raise her tail to meet the mating of the male rabbit.
artificial insemination
Significance of artificial insemination: Artificial insemination of rabbits refers to the artificial extraction of male rabbit semen, which is imported into the reproductive tract of female rabbits after quality inspection and dilution to make them pregnant. Its advantages are that it can make full use of excellent breeding rabbits, improve the quality of rabbits, quickly popularize improved varieties, reduce the feeding amount of breeding rabbits and reduce the feeding cost; Reduce the spread of diseases; Overcome some reproductive obstacles, such as the great difference between male and female rabbits, which is convenient for intensive production management. But it needs skilled operation technology and necessary equipment.
Main equipment and drugs: sperm collector: a hard plastic or rubber tube with a shell length of 12- 14 cm (which can be replaced by condoms), which is twice as long as the shell; Sperm collection bottle; Vasodilator: 2 ml syringe, latex tubule, plastic vas deferens; Low power microscope; Disinfecting alcohol; Diluent (the simplest is to use 5% physiological glucose saline); Ovulation stimulating hormone, etc.
Technical key to improve the effect of artificial insemination in rabbits;
Good semen quality: In order to obtain the ideal mating effect, it is necessary to have good semen, and only by microscopic examination can it be used for fertilization.
Strict disinfection: All instruments and drugs used in artificial insemination must be cleaned and strictly disinfected. If disinfection is not strict (including diluent needed for artificial insemination), it will not only affect semen quality and pregnancy rate, but also lead to reproductive tract diseases of female rabbits.
The correct choice of ovulation hormone: rabbits are animals that stimulate ovulation, and they will not ovulate without mating or drug stimulation after estrus. Therefore, female rabbits must be stimulated to ovulate before insemination. Chorionic gonadotropin (HCG), lutein (LH) and other ovulation-promoting hormones (such as ovulation-promoting No.3) are generally used to stimulate ovulation. Gonadotropin and estradiol in pregnant horse serum can induce estrus and then stimulate ovulation. Usually, female rabbits are injected with ovulation induction hormone 0.5- 1.0 hour before insemination or immediately after insemination.
The exact site of insemination: the ventral opening of the female rabbit's bladder is about 5 ~ 6 cm in the vagina, which is equivalent to the vaginal opening and parallel to the vagina under the vagina. During insemination, it is easy to insert the vas deferens into the urination port by mistake and input semen into the bladder; If the vas deferens is inserted too deep, it is easy to input semen into one uterus (rabbits are bimorphs), resulting in empty arms on the other side. Therefore, during insemination, the insemination device should be inserted into the posterior wall of vagina to a depth of about 6-7 cm, and then turned to the ventral surface after passing through the urethral orifice until it is inserted into the cervix to a depth of 8- 10 cm, so that the sperm can enter the two uterus from the cervix at the same time, which is beneficial to increasing the number of pregnant babies.
Pregnancy diagnosis
The technique of judging whether a female rabbit is pregnant after mating is pregnancy diagnosis. There are three methods for pregnancy diagnosis: compound examination, weighing examination and palpation examination.
Compound test method
About 7 days after mating, the female rabbit was sent to the male rabbit cage to mate again. If the mother rabbit refuses to mate, it means that she may be pregnant. On the contrary, if she accepts mating, she can be considered not pregnant. This method is not accurate.
Weighing inspection method
The female rabbits are weighed before mating, and once every 10 day. If the weight is significantly higher than before mating, it means that she is pregnant. If there is not much difference in weight, she is considered not pregnant. But its accuracy is not high.
Touch tire inspection method
The method of touching the mother rabbit's abdomen to determine whether she is pregnant is called fetal touch test, which is often used in production practice. The specific method is: put the mother rabbit on a table or flat ground, grab the skin of the ear and neck of the mother rabbit with one hand, make the rabbit head face the fetus-touching person, and the thumb and other four fingers of the other hand are splayed, with the palm facing up, reaching out to the abdomen of the mother rabbit and groping gently from front to back along the abdominal wall. If the abdomen feels as soft as cotton, it is not pregnant. If you feel the abdominal wall is tense, and there is a ball sliding like a peanut in the abdomen, and it is elastic, it is a fetus. But pay attention to the difference between an embryo and a dung ball, which is hard, inelastic and rough. The method of touching the fetus is simple and accurate, but care should be taken not to lift the female rabbit off the ground, let alone index the number of embryos by hand, and stop wiping the fetus from 15 to 28 days after mating. So as not to cause miscarriage.
Those who are not pregnant after pregnancy diagnosis should be supplemented in time to reduce the number of empty pregnant female rabbits in order to improve the fertility of female rabbits.
Measures to improve the fertility of rabbits
In view of the main factors affecting the rabbit's fertility, in order to improve the fertility, the following measures can generally be taken:
1. Strengthen the selection of breeding rabbits: select the male and female rabbits that meet the requirements of feeding standard in strict accordance with the selection requirements; In order to avoid inbreeding, scientific groups should match.
2. The structure of breeding rabbits is reasonable: First, the male and female rabbits should maintain an appropriate proportion. The male-female ratio of general commodity rabbit farms and farmers is1:8 ~1:kloc-0/0, and that of pure rabbit farms is 1: 5 ~ 1: 6. Pay attention to the mating intensity of male rabbits and arrange the mating times of male rabbits and female rabbits reasonably. Second, the age structure is reasonable. Under normal circumstances, the ratio of old, mature and young rabbits is 20:50:30.
3. The nutrition of male and female rabbits should be reasonably matched: the nutritional level of empty pregnant rabbits and early pregnant rabbits should be moderate, and it is better not to be fat or thin. Both male and female rabbits should ensure the supply of protein and vitamins, especially vitamins A, E, D, which are properly matched with green feed, which has a good effect on improving reproductive performance.
4. Timely breeding
Include arranging timely breed season and breeding time. Although rabbits can reproduce all the year round, the hot summer climate makes male and female rabbits lose appetite and male rabbits lose their libido. Most female rabbits are unwilling to accept mating. Even if there are many weak fetuses and stillbirths, young rabbits suffer from "yellow urine disease" and are not easy to survive. Therefore, it is generally not suitable for breeding in midsummer; However, in order to reduce the influence of "infertility in summer" on the number of babies born every year, it is suggested to breed a batch of rabbits before beginning of autumn 1 month, and babies born after beginning of autumn have a high survival rate. In southern areas such as Sichuan, winter and spring are good seasons for breeding. Breeding is easy, and the survival rate of young rabbits is high. It is necessary to breed more and have more babies. Timely breeding should not only arrange the season, but also seize the best breeding time of estrus female rabbits to improve the breeding rate. In addition, breeding should be done early and late at high temperature, and at noon at cold time.
4. Artificial aphrodisiac
In actual production, some female rabbits are out of estrus for a long time and refuse to mate, which affects their reproduction. In addition to strengthening feeding management, artificial estrus methods such as hormones and seduction can also be used. Estradiol and pregnant horse serum gonadotropin can induce hormone estrus, and ovulation stimulating hormone 3 has a better effect on estrus and ovulation of female rabbits. For female rabbits that have been out of estrus for a long time or refused to mate, put them in male rabbit cages and let them chase and climb their hips, or for female rabbits with more vulvar hydrops, use artificial massage to stimulate female rabbits to ovulate in estrus and promote their tails to accept mating.
5. Repeated mating and double mating
In order to increase the number of effective sperm entering the reproductive tract of female rabbits, repeated mating or double mating can be used. Repeated mating refers to mating with the same male rabbit again within a few hours after the first mating. Repeated mating can increase the fertilization chance of female rabbit eggs, improve the conception rate and prevent false pregnancy, especially when using male rabbits who have not mated for a long time. Because for the first time, there are more dead sperm in the semen of this male rabbit; Double mating means mating with another male rabbit after the first mating. Double mating can avoid male rabbit infertility, and can obviously improve the conception rate and litter size. Two-line breeding is only suitable for commercial rabbit production, not for breeding rabbit production, in case of hybrids. In practice, we must pay attention to wait until the smell of the first male rabbit disappears before mating with another male rabbit. Otherwise, the smell of other male rabbits may cause the female rabbit to fight, which may not only lead to successful mating, but also bite the female rabbit.
6. Check the fetus in time after breeding to reduce the empty mind. Rabbits are kept in a cage to avoid "false pregnancy".
7. Correct use of frequent propagation method.
Frequent breeding is also called "blood matching nest" or "blood matching", that is, the female rabbit breeds on the day or the next day after delivery, and breastfeeding and pregnancy are carried out at the same time. Using this method, the breeding speed is fast, but because breastfeeding and pregnancy are carried out at the same time, it is easy to damage the physical condition of the mother rabbit, shorten the utilization cycle of the breeding rabbit, and the natural elimination rate is high, which requires good feeding management and nutrition level. Therefore, in order to produce commercial rabbits by frequent breeding, we must use high-quality feed to meet the nutritional needs of mother rabbits and young rabbits, strengthen feeding management, weigh the mother rabbits regularly, and stop blood matching once the weight drops obviously. Three methods should be used alternately in production, namely, frequent breeding, semi-frequent breeding (7 ~ 14 days after delivery) and delayed breeding (after weaning).
8. Create a good environment and keep proper light intensity and time.
Do a good job of protecting and taking the fetus, and don't feed moldy, spoiled, frozen and pesticide-treated feed during pregnancy to prevent disturbing and scaring the mother rabbit, so as not to cause miscarriage.
Main factors affecting rabbit fertility
(1) Environment: All external factors acting on rabbits are collectively referred to as environmental factors, such as temperature, humidity, airflow, solar radiation, noise, harmful gases and pathogenic microorganisms. Environmental temperature has obvious influence on the reproductive performance of rabbits. Everyone knows that rabbits are infertile in summer. When the ambient temperature exceeds 30℃, the appetite and sexual desire of rabbits will decrease. If the high temperature continues, the sperm produced by the testis of male rabbits will be reduced, or even no sperm will be produced, or sperm will die and deform. The effect of high temperature on male rabbits' sexual desire is short-lived, but it takes about two months to show the effect on semen quality. Because it takes 1-2 months for sperm to mature and excrete. This is the main reason why rabbits, especially long-haired rabbits and large meat rabbits, have difficulty in breeding in autumn (September-65438+1October). So don't mistake "infertility in summer" for that rabbits are not worth breeding in summer.
Low temperature and cold also have some influence on rabbit reproduction. If the ambient temperature is lower than 5℃, the sexual desire of rabbits will decrease and their reproduction will be affected. Pathogenic microorganisms often affect the reproduction of rabbits with the change of temperature and humidity. Because rabbits like to be dry, wet, clean and dirty, wet and dirty environment often leads to the breeding of pathogenic microorganisms, causing intestinal diseases, coccidiosis and scabies, affecting the health of rabbits and thus affecting their reproduction. Strong noise and sudden sound can cause stillbirth or abortion in rabbits, even make mother rabbits swallow, bite young rabbits or cause infertility due to fright. The attack of thief wind in cold winter is easy to make rabbits catch cold and pneumonia, and solar radiation in hot summer is easy to make rabbits suffer from heatstroke. These are all bad environmental factors that affect rabbit reproduction.
(2) Nutrition: Practice has proved that high nutrition level often leads to obesity in rabbits, and a large amount of fat is deposited in ovarian connective tissue of obese female rabbits, which affects the development of egg cells, reduces ovulation rate and leads to infertility. Low nutritional level or malnutrition also affects the fertility of rabbits. Because the reproductive performance of rabbits is greatly affected by pituitary function, malnutrition directly affects the semen quality of male rabbits and the pituitary function of female rabbits, and the ability to secrete hormones is weakened, which makes the egg cells unable to develop normally and leads to long-term infertility of female rabbits.
(3) Diseases: Diseases affecting rabbit reproduction include hereditary physiological defects and common diseases of reproductive system. Such as female rabbit vaginal stenosis, male rabbit cryptorchidism, monogamy. Because cryptorchidism or monogamy can't make male rabbits produce sperm, or the ability to produce sperm is poor, mating can't make female rabbits conceive or the pregnancy rate is not high. Another example is vaginitis, metritis or intrauterine stillbirth caused by "dystocia" of female rabbits; Hysteromyoma and orchitis in male rabbits can obviously affect the reproductive performance of female rabbits.
(4) Improper use:
Long-term empty pregnancy or early and late first mating age of female rabbits often leads to ovarian dysfunction and difficult pregnancy. Long-term non-mating of male rabbits or excessive use in breeding season will lead to decreased sexual desire or ineffective mating.
(5) Aging of breeding rabbits:
Practice has proved that the age of breeding rabbits obviously affects their reproductive performance. The reproductive performance of 1 ~ 2-year-old male and female rabbits increases with age. After 2 years old, the reproductive performance gradually declines, and after 3 years old, the reproductive performance is obviously weakened, the mating rate is low, the number of offspring is small, and the survival rate of offspring rabbits is low, so it is not suitable for breeding rabbits.