Key Points of Artificial Insemination Technology for Rex Rabbits and an Analysis of Its Advantages and Disadvantages

Rabbit artificial insemination mainly includes semen collection, semen quality evaluation, dilution, preservation, transportation, insemination and other steps. The operation of rabbit artificial insemination equipment is as follows:

1. Preparation before semen collection

(1) Preparation of the semen collector. There is currently no unified specification or standard for the semen collector. The semen collector is generally composed of two parts, an artificial vagina and a semen collection vessel. The structure and production of two types of artificial vaginas are introduced here for reference in practice. A. Simple-type artificial vagina. Select a hard plastic tube or bamboo tube with a diameter of 3-4 cm (inner diameter 2.5-3 cm) as the outer shell of the artificial vagina, take an inner tube and turn both ends outward, fix it on the outer shell with rubber rings, drill a hole in the middle of the outer shell and install a water injection piston, and connect a small glass bottle or sampling test tube below as the semen collection vessel. Before use, disinfect it first with 75% alcohol, then rinse it with normal saline. When in use, inject water at 50-60°C from the piston of the outer shell until it fills about 2/3 of the space inside the shell; during semen collection, it is appropriate to maintain the water temperature at 38-40°C.

(2) Preparation of the insemination device. Rabbits have no dedicated insemination device; generally a 5-10 ml glass syringe is used as the insemination device

(3) Disinfection of artificial insemination instruments.

(4) Training of semen collection bucks. Bucks that have not previously been used for semen collection need to be trained. Select a healthy doe in estrus and let the buck mount, but not mate.

2. Semen collection

Semen collection is generally carried out in the buck's cage. Prepare the semen collector and adjust the temperature to 38-40°C, and apply a little petroleum jelly or soap solution to the open end to provide lubrication. When Shuihu Breeding Company uses an estrous doe as the semen collection mount rabbit, the collector holds the doe's ears and neck skin with one hand, restrains the doe well, and makes its hindquarters face into the cage; with the other hand, he extends the artificial vagina under the doe's abdomen, with the open end of the artificial vagina pressed tightly against the doe's vulva, making the artificial vagina form a 30-degree angle with the horizontal plane. When the buck, after being teased, mounts the doe's back, the artificial vagina must be aligned quickly and accurately with the angle and position of the vagina to facilitate insertion of the penis. When the buck's hindquarters thrust forward suddenly, ejaculation is completed. The buck then makes a "coo-coo" sound and falls over. At this time, the artificial vagina should be retracted and its open end turned upward to prevent the semen from spilling. Remove the semen collection vessel and send it to the artificial insemination room for examination.

The operation of semen collection with an artificial mount doe is basically the same as above, but the requirement is a buck with strong libido or one that has been trained. The semen collection frequency is 1-2 times per day, and after 5 consecutive days, 1 day of rest should be given.

The normal ejaculate volume is 0.5-2 ml. Good semen is milky white and thick. Generally, the greater the sperm density, the whiter and thicker the color, and these are all relatively good semen.

3. Insemination

For insemination, first carry out estrus identification of the doe

(1) Ovulation treatment before insemination. Because domestic rabbits are induced ovulators, ovulation treatment must be carried out before insemination. Methods include injecting each rabbit with 5-10 ug of ovulation-inducing No. 2 (LRH-A-2) or 50 IU of human chorionic gonadotropin dissolved in 0.2 ml of normal saline via the ear vein; a vasectomized buck may also be used to mount, but some believe that the effect of stimulation by mounting alone is not ideal. Generally, insemination is carried out immediately after inducing ovulation.

(2) Insemination method. During insemination, first take the doe out and place it on a table. The operator holds the doe's hindquarters tightly with one hand, wipes away dirt from the doe's external genitalia with a 75% alcohol cotton ball or iodine cotton ball, and disinfects the vulva. With the other hand, he holds the insemination tube and inserts it along the dorsal side of the vaginal wall 7-9 cm to near the cervix, then slowly pushes in 0.3-0.5 ml of semen, with no fewer than 10 million effective sperm. While inserting, move the insemination tube back and forth several times to stimulate the doe. After withdrawing the insemination tube, raise the doe's hindquarters for a moment and pat it once to prevent backflow of semen. The inverted-lifting method also gives very good insemination results, that is, lightly clamp the doe's head and neck between the operator's knees, grasp and lift the rabbit's rump and tail with the hand, and inseminate with the insemination tube in the other hand. A two-person operation may also be adopted, with one person restraining the doe and the other performing insemination.

Advantages and disadvantages of artificial insemination in Rex rabbits:

Rex rabbit artificial insemination technology is the simplest and most effective method adopted for the purpose of breeding stock rabbits and producing commercial rabbits, and is an important means of conducting scientific rabbit farming and realizing the modernization of rabbit production.

(1) Disadvantages     If the rabbit farm itself does not have a high production level and the technology is not up to standard, artificial insemination is very likely to cause an increase in doe endometritis, a low conception rate, and a small number of offspring. It is recommended that technicians first learn the technology and then conduct small-scale artificial insemination trials; or adopt a combination of natural mating and artificial insemination, and then promote it as the production level and technology continue to improve.

(2) Advantages of rabbit artificial insemination:

① It can expand the male-to-female ratio and reduce feeding costs. The male-to-female ratio for natural mating is 1:4-6, while artificial insemination can expand it to 1:80-120, improving the utilization rate of improved-breed bucks. Eliminating poor bucks and reducing the number of breeding bucks kept saves feed and equipment costs, greatly reducing feeding costs.

② It solves mating difficulties. In particular, extra-large meat rabbits have larger body sizes, making natural mating difficult and directly affecting the conception rate of does. The use of artificial insemination technology can solve this mating difficulty.

③ It overcomes selective mating between bucks and does. In natural mating, both bucks and does show preferences, which affects the conception rate. Only artificial insemination can solve this selective mating and improve the conception rate. In addition, if an individual excellent breeding buck cannot mate naturally due to trauma, especially leg injury, artificial insemination can fully realize the utilization value of the excellent breeding buck.

④ It is a major reform in breeding work. The use of artificial insemination technology does not require single-cage mating and recording. Not only are records accurate, but through testing the semen quality of bucks, the production performance of offspring is improved, accelerating the breeding process.

⑤ It reduces the spread of disease. This mainly refers to the spread of diseases of the buck's mating organs. When the buck's mating organs are diseased, the buck's semen is contaminated; if natural mating is used, it causes vaginal disease in does.

⑥ It expands the gene pool. Semen freezing technology can achieve a conception rate of 80-90%, unrestricted by the buck's age, time, region, or national borders. No matter how long the period, excellent lines can be preserved by freezing technology, and their semen can be used to reproduce offspring.

⑦ It is easy to promote. Artificial insemination technology is simple and easy to perform and does not require relatively precise and complex equipment. Generally, a person with a junior high school education or above can operate independently after 10-15 days of study and practical operation training.