Artificial insemination technology The application of artificial insemination technology is a major advance in chicken breeding methods. First, the use of artificial insemination avoids the influence of fertility due to breeding behavior and the relationship with the spouse. At the same time, through the identification of semen quality, cockerels with poor performance can be eliminated, so that excellent cocks can multiply their offspring. Secondly, the number of breeding males can be greatly reduced and feeding costs can be reduced. Artificial insemination can increase the male-female ratio from 1:10-15 to 1:20-30 or even 1:50, which accelerates the promotion of improved varieties and achieves the purpose of improving efficiency and increasing efficiency.
(1) Semen collection techniques Artificial insemination of roosters requires the selection of healthy individuals with excellent production performance, appropriate age, and strong males. When lifting a pair of wings of a rooster, the tail should be upturned, sexually reflexed, cloacal cavity large, moist and loose. Roosters co-cultured with hens should be kept in isolation from the hens at least one week in advance. The cockerels used for fine collection are best kept in single cages to prevent fighting and crawling each Other, affecting the value of sperm collection. Before the training, the roosters cut the feathers about 1 cm wide around the cloaca to reduce the pollution during the collection. Training 1-2 times a day, usually 3-4 days after most of the roosters can produce semen. Roosters that do not have semen should be eliminated. The commonly used methods for extracting sperm include massage method, spacer method, chicken method, and electrical stimulation. Among them, the massage method is the safest and simplest, and can reduce the degree of semen contamination, so it is most commonly used. Massage semen is usually performed by two people, one is Baoding, and the other is sperm. Baoding members took one leg of each cock with both hands and naturally separated. The thumb held the chicken wings so that the head of the rooster was clamped back under the left axe, similar to the natural mating posture. The left hand of the spermachanist pulled down and clung tightly against the back of the cock and licked gently towards the tail, so he massaged it several times and caused the cock to be sexy. Sexual reflexes after several massages in the left hand, immediately flip the left hand, and use the left palm to pull the tail feathers to the back, while the right palm clings to the soft cock belly, separates the thumb and index finger, and places it on the lower edge of the pubic bone. Times; when the cloaca opens and exposes the degenerate copulator, the thumb and index finger of the left hand squeeze the both sides of the anal ring, and the semen flows out of the copulator. At this time, the right hand quickly puts the spermatic orifice into the cloacal cavity to take up the semen. The Baoding member then returned the rooster to his cage. The number of times that a rooster is picked is appropriate 3 times a week. The best 3-4 hours before the rooster picking sperm to prevent defecation, affect semen quality. All appliances should be strictly cleaned, disinfected and dried. The collected fresh semen should be stored in a thermos flask at 25-30°C immediately, protected from light, and used up within 30 minutes. The main purpose of diluting semen is not only to increase the vitality of the sperm and prolong its life, but also to facilitate handling and storage. Commonly used diluents include normal saline, 5.7% glucose solution, and egg yolk glucose solution (100 ml of water plus 1.5 ml of fresh egg yolk and 4.25 g of glucose). The dilution ratio is 1:1. Semen dilution should be completed within 20 minutes after sperm collection. The short-term storage temperature of fresh semen is preferably 2-5°C.
(2) Insemination Techniques The hens used for insemination should be high-yield breeder hens that have already laid eggs, have good body condition, and have no cloacal inflammation, and their age should not be less than 200 days. Insemination was carried out by two people. One was anal and the other was insemination. The assistant holds the hen's wings with her left hand and lifts it up. Place the hen head upwards and the anus face down. Place the right palm under the hen's pubic bone. Use the right hand tiger's mouth to push the hen's abdomen to the anus and place it softly. The fallopian tube in the cloaca. The mouth will come out and the hens will be on the ground if they have faeces. The hen's cloaca was then immediately directed towards the inseminator, waiting for insemination. The inseminator uses the vas deferens to deliver the semen into the vaginal opening, about 3 cm deep, and pulls the vas deferens immediately after the infusion. At the same time, the assistant's right hand lifts the pressure on the hen's abdomen, restores the cloacal cavity, and then places the hen back into the cage to complete the insemination.
(3) The amount of insemination and frequency of insemination The amount of insemination and the number of insemination should be based on the quality of semen. High sperm motility, high density, less insemination, and dilution and insemination. A normal insemination amount of fresh semen should not be less than 0.25 ml. After an insemination, the sperm can survive in the hen's fallopian tube for a period of time. Generally, the fertilization rate of the egg reaches a peak on the 5th day after insemination, and then begins to decline. Therefore, the interval between two inseminations is preferably 5 days. The insemination period should generally be performed every afternoon when most hens produce eggs. Insemination in the morning, hard shell eggs in the uterus of the hens, the fertilization rate is low. Checking the quality of semen is an important part of a good insemination. Normal semen is a milky, viscous fluid. The blood was mixed pink; it was yellowish-brown when it was contaminated with faeces; it was a pink-white floc when it was mixed with urate. If the transparent liquid is mixed in too much, you will see water stains. Check the vitality of sperm must be completed within 20 minutes after sperm collection. For examination, take 1 drop of the same amount of semen and saline, place it on one end of the slide, mix well, and place a cover glass. Under a condition of 37°C, the microscope was examined with 200-400 magnifications. Spermatozoa with linear motion are capable of fertilization, and sperm in both circular motion and swing motion are not capable of fertilization. Semen with high vitality and high density can be observed under a microscope. Check sperm density can be used to estimate the density of sperm, the specific method is to observe the density of the visual field in 400 times the microscope, and estimated with the naked eye. Sperm density is divided into 3 levels: Level 1 is filled with sperm in the entire field of vision, and there are almost no gaps between spermatozoa. There are about 4 billion spermatozoa per milliliter of semen. Level 2 shows that the distance between spermatozoa is more obvious in the field of vision. There are about 2 billion to 4 billion spermatozoa per milliliter of semen. In level 3, spermatozoa spacing is seen in the field of vision. There are less than 2 billion spermatozoa per milliliter of spermatozoa. When less than 2 billion sperm per milliliter, fertilization ability is poor. The method of checking the deformity rate is to take one drop of semen on a slide, smear the piece, dry it, fix it with 95% alcohol for 1-2 minutes, rinse, and then stain with 0.5% gentian violet for 3 minutes, rinse, and dry it on the microscope. Check it out. Each time 300-500 sperm were counted, the malformation rate was calculated. Frequent spermatozoa also have lower semen fertilization rates.
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