Pig artificial insemination technology

The study of artificial insemination of pigs was not successful in horses until the end of the 19th century and the beginning of this century after the first successful artificial insemination of dogs on the ground by the Italian physiologist Byron Ginny in 1780, and then used in cattle, sheep, pigs and other livestock. It was not until the 1930s that a complete set of operation methods was initially formed, and from the experimental stage to the practical stage, it became an important means of breeding and improving livestock.

Advantages and disadvantages of artificial insemination in pigs

"A sow is a good litter, and a boar is a good slope." This sentence strongly illustrates that although boars and sows each account for 50% of the genetic influence of offspring, under normal natural mating conditions, a boar can be mated with many sows, while a sow can only be mated with one or two boars, producing 2.0 to 2.5 births a year. It can be seen that boars are much more important than sows. If good boars are fully utilized, their impact on offspring will bring several times or even dozens of times of benefits to the pig industry. In the case of natural mating, a boar can bear the task of mating a maximum of 25,30 sows a year. Obviously, the use efficiency of boars has not been brought into full play, so how to give full play to the role of good boars? The wide application of artificial insemination in pigs makes it possible.

Pig artificial insemination is the simplest and most effective method for breeding and commercial pig production, and it is an important means to raise pigs scientifically and realize the modernization of pig production. Its advantages are as follows:

The main results are as follows: 1. Improve the utilization rate of excellent foreign boars and save the feed and cost of raising boars.

Natural mating, the ejaculation volume of boars can only match one sow, using artificial insemination technology, the ejaculation volume of boars can match 10-30 sows. In the case of natural mating, one boar undertakes the breeding task of 25,30 sows a year and breeds 600,800 piglets, while using artificial insemination technology, an excellent foreign boar can undertake the breeding task of 400,1500 sows and breed more than 10,000 piglets.

2. The advantages of pig artificial insemination on pig heredity and combined breeding.

By preserving the semen of superior boars or endangered pig breeds, the use of boars is not limited by their physiological years, and the preservation of genetic resources can be realized, and the cross-group or cross-regional use of boars can be more convenient, economical and safe. it is convenient to introduce genes from foreign populations, and the reduction of demand for boars can increase the selection intensity of boars. A large number of offspring of fine boars can be obtained, and their excellent genes can be popularized rapidly, thus accelerating the diffusion of genetic progress; establishing a balanced population structure by controlling the use of boars, and improving the estimation efficiency of genetic parameters and breeding values. Compared with natural mating, 50% and 100% artificial insemination increased the cumulative genetic progress of 10-year selection by 14% and 17%, respectively [5]. Therefore, artificial insemination can technically solve the problem of large number and small scale of pig breeding farms in China, and realize the joint breeding of pigs, which is also one of the most economical and effective means to improve the efficiency of pig breeding and improve the breeding system of improved breeds in China.

In a word, artificial insemination through the semen of foreign excellent boars can accelerate the genetic progress of pig breeding, increase the coverage of excellent genes in pig herds, improve the growth rate of pigs, reduce the ratio of feed to meat, and improve the evenness and uniformity of pigs, and finally improve the product quality to a higher level, so that China's pig breeds can win a place in the international pig industry competition. Vigorously carrying out the research on the application and popularization of artificial insemination technology of out-breeding pigs can quickly and safely enable excellent breeding pigs to exchange genetic resources in the form of semen between pig farms and pig farms. In this way, the joint breeding of pigs in a large range of farms and inter-farms can be realized in the shortest time.

3. It is beneficial to the layout of varieties.

Artificial insemination can give full play to the role of excellent lean boars, speed up the production of commercial lean boars, and unified sperm supply can scientifically adjust the layout of breeds.

4. Overcome the difference of physical size and make full use of heterosis.

In the case of natural mating, it is difficult for a big boar to mate with a small sow, and vice versa. Some pigs are fond of sex, and it is difficult for boars and sows who do not like each other to breed. In this way, it will cause some difficulties for the conservation of excellent boars (when designated for breeding) and the improvement of the quality of breeding pigs. For the commodity market, it will also cause some difficulties to make use of heterosis to cultivate commercial pigs with good fattening performance, high lean percentage and excellent body shape, especially for export pigs. By using artificial insemination technology, the above difficulties can be overcome as long as the sows are in stable estrus, and mating can be selected according to the need, which is beneficial to the conservation of high-quality breeding pigs and the full play of heterosis.

5. Reduce the spread of disease.

Boars and sows undergoing artificial insemination are generally pigs that have undergone health examination. as long as they are bred in strict accordance with the operating procedures and reduce the pollution in the process of semen collection and semen treatment, the spread of some diseases, especially reproductive tract diseases, can be reduced. so as to improve the conception rate and litter size of sows.

6. overcome the differences in time and region, and breed in time.

During natural mating, the phenomenon that sows are in estrus but there is no boar to use, or the need for breed improvement but the introduction of boars is more difficult to introduce boars is always perplexing people in the pig industry. With artificial insemination, boar semen can be treated and preserved for a certain period of time. Estrus sows can be inseminated at any time, semen (or frozen semen) can be purchased without introducing boars, which is easy to carry and economical. And can ensure the quality and timely breeding, so as to promote the improvement of social and economic benefits of the pig industry.

7. Save manpower, material and financial resources and improve economic benefits.

Compared with natural mating, the number of boars raised by artificial insemination is relatively reduced, saving some labor, feed, barracks and money. even if a suitable boar station is re-established, the overall economic benefit will still be improved; if you simply buy pig sperm, it will create more economic benefits. At the same time, artificial insemination is also an important condition for centralized weaning and centralized breeding in pig farms, and good technical conditions of pig artificial insemination can also improve the conception rate of sows, because the boars used in artificial insemination are strictly selected. and after each semen must undergo microscopic examination, this is natural mating is very difficult to do.

The disadvantages of artificial insemination: if the production level is not high and the technology does not pass, it is likely to cause sow hysteritis, low conception rate and low litter size. It is suggested to learn the technology first, and then carry on the small-scale artificial insemination experiment, or the combination of natural mating and artificial insemination, and then popularize it with the continuous improvement of production level and technology.

Benefits of artificial insemination in pigs

Here is an example of pig artificial insemination and natural mating to make a cost comparison. If there is a pig farm with 1000 breeding sows, such as natural mating, a boar can undertake the breeding task of 25 sows every year, then natural mating requires raising 40 breeding boars, such as artificial insemination, a boar can undertake the breeding task of 150,400 sows, here is calculated according to the artificial insemination of a boar, so that the pig farm only needs to raise 4 boars. Cost comparison calculation: based on the annual feed consumption of 800Kg per boar, the feed cost is at least 1500 yuan / year, so artificial insemination can save 54000 yuan in feed cost. Based on the annual elimination of 1 big 3 boars, 13 boars were eliminated by natural mating and 2 by artificial insemination. Based on the purchase fee of 4000 yuan for each breeder boar, artificial insemination saved 44000 yuan for the purchase of boars. The cost of insemination per sow by artificial insemination is about 33 yuan per year (including disposable bottle, vas deferens, diluent, etc.). It costs 33000 yuan to breed 1000 sows. According to comprehensive calculation, the pig farm using artificial insemination to breed 1000 sows can save at least 65000 yuan. In addition, the cost of building a boar pen and labor costs can be saved. The economic benefits of using artificial insemination are obvious. Therefore, on the premise of increasing the conception rate and stabilizing the litter size, the large-scale application and popularization of artificial insemination technology will produce rich economic and social benefits.

It can be seen that compared with natural mating, the advantages and benefits of pig artificial insemination are very significant.

Operation technique of artificial insemination in pigs

1. Training of boars

Boars who collect semen from fake sows for the first time must be trained. Training should be patient, train repeatedly, do not act in haste, and forbid coercion, beating, intimidation, and so on. Practice has proved that newly used boars, like backup pigs, mating once or twice is helpful to training, and the training methods are as follows:

① smeared the urine or vaginal mucus of the estrus sows after the fake sows to induce the boars to climb over the fake sows. After several times of semen collection, the boars can be trained successfully.

After a sow in estrus was seduced by a sow in the semen collection room, she refused to mate. When the sexual impulse of the boar reached its peak, the sow was quickly driven away, and then the boar was induced to climb directly across the fake platform to collect sperm.

③ will train the boar next to the semen collection room, let it be familiar with another trained boar to climb across the semen collection, and then induce it to climb across the semen collection. The production proves that if one boar drives another boar to the front of the fake sow after semen collection, most boars will show a strong interest in the fake sow and will carefully observe the fake sow and climb across the fake sow in a few minutes.

④ should pay special attention to the first semen collection when training boars. The first semen collection should be complete and ensure that boars will not be hurt or stimulated in any way. If boars are not successfully trained for half an hour, they should be driven away amicably, waiting for the right time or more about the vicinity of the semen collecting table to make them familiar and then try again.

2. Semen collection

Preparation before ① semen collection

Select and train "on-site" expert operators, and select and train one or more people who undertake the technical work of artificial insemination in the pig farm. The success of artificial insemination requires the person to be accurate, patient, confident, careful and enthusiastic and with the spirit of research. The personnel must skillfully master how to clean and disinfect artificial insemination technical equipment and instruments. How to train boars and collect, treat and store semen, can accurately identify oestrus, timely breeding and so on.

Semen collection room, semen collection should generally be standardized in the sperm collection room, when the boar is driven to the semen collection room can cause boar sexual excitement. The semen collection room should be designed to be spacious, quiet and clean. If the fake sows are to be stable, they had better be fixed in the middle of the semen collection room. In order to prevent individual boars from harming people, protective fences should be set up on both sides of the sperm collection room. "figure 1" is a proposed layout of semen collection room for reference in actual production (the area is about 3 ╳ 3 meters, and the actual sperm collection area is about 2.5 ╳ 2.5 meters).

The preparation of Taiwan livestock and the Taiwan livestock used by boars to collect semen are all called fake sows in production. Fake sows have a variety of designs, according to the actual situation can be designed for single-end type, high and low adjustable activity, and so on, the simplest way is to make a bench (semen collection table), and does not necessarily cover pig skin, and does not have to pursue the shape of a pig, length can be 1cm 1.3 meters, height 50 65 cm, back width 20 25 cm, in order to facilitate the training of boars, the sperm collecting table can also be shorter, shorter and lighter. Steel frame and wood face are often used in the production, which are covered with thick canvas or gunny bags. "figure 2" is a simple style of collecting semen.

For the preparation of artificial insemination laboratory and related equipment and facilities, in order to facilitate the preparation of semen collection utensils, semen testing, semen dilution and dilution, semen storage, disinfection and cleaning of artificial insemination instruments, an "artificial insemination laboratory" within the pig farm should be established. In the actual construction, the laboratory should be located near the semen collection room as far as possible, and if possible, it should be directly connected with the semen collection room to facilitate the rapid processing of semen. A window is used to connect the artificial insemination laboratory and the semen collection room to enhance epidemic prevention. The construction of artificial insemination laboratory should fully consider the requirements of hygiene and epidemic prevention, the floor of the room should be easy to clean, the wall can be scrubbed, and washable worktables, sewage sinks and drying racks should be arranged. Complete water and electricity, adjustable room temperature, hot and cold water sources are preferred. The layout of the laboratory depends on the specific operating procedures. The use of small rooms is easy to keep clean and adjust the room temperature. Figure 3 is a schematic diagram of an artificial insemination laboratory. According to the operation, it is divided into three parts: wet zone (preparation of diluent, cleaning equipment, dilution of semen); dry area (examination of semen); sub-loading area (sub-packing of semen, preservation of semen, etc.).

The equipment for artificial insemination and semen collection mainly includes: semen collection bottle (all kinds of containers can be used, but it is better to have the effect of heat preservation and insulation, so that it can be sterilized and easy to clean); funnel; sterilized surgical gauze; disposable latex gloves (pay attention to non-toxic); microscope (magnification can be 100,400, 1000 times, preferably equipped with 2 eyepieces, microscope incubator, in order to maintain the temperature of semen samples); glass slides Eyedroppers; thermometers; beakers, measuring cylinders and bottles of various capacities (glass or plastic, for preparing diluent, diluting semen and sub-filling semen, etc.); semen bottles and nozzles; semen preservation facilities (polyethylene or polystyrene foam boxes, cold and hot water bags, etc., for short-term storage of semen; thermostat cabinet or incubator) Disinfection facilities (disinfection tray or electric heating network, electric vas deferens disinfection equipment, high pressure disinfector, etc.); vas deferens; distilled or reverse osmosis water; drying cabinets (drying and storage of all semen collection and testing equipment).

The field with good conditions should also be equipped with water softener, colorimeter or spectrophotometer, water bath thermostat, heater / magnetic agitator, etc.

② semen collection method: holding boar semen is a widely used method at present, which is simple, accurate and efficient. During the operation, the semen collector put on disinfection gloves and stood on one side of the fake Taiwan animal. First, the boar foreskin was washed and disinfected with 0.1% potassium permanganate solution. After the boar climbed onto the Taiwan animal, the boar's penis was rubbed with his hand to induce it to protrude, and it was introduced into the palm of the empty fist to rotate for a moment. Hold the spiral penis tortoise head with a rhythm from light to tight with fingers to prevent it from turning. When the penis is fully erect, homeopathic stretch forward (not forced), while the fingers are elastic, rhythmically adjust the pressure, the result will cause boar ejaculation. Stop the elastic adjustment during ejaculation, open your fingers slightly to expose the tortoise head, and let the semen ejaculate into another hand-held collection bottle with filtered gauze and heat preservation. After the boar stops ejaculating for the first time, the boar does not move according to the original position, and then resumes the elastic adjustment of extrusion to ejaculate for the second or third or fourth time until all ejaculation is finished.

Matters needing attention in ③ semen collection

Semen collection frequency: Reserve boars collect semen once a week, production boars collect semen twice, no more than 3 times if necessary, frequent semen collection is strictly prohibited.

Squeeze the urine out of the boar's allantoic bag before semen collection, then wash and disinfect the boar's foreskin. If the pubic hair is too long, it should be cut short.

In the process of semen collection, the attitude of the staff should be gentle, do not be rude, the operation should be standardized, and be careful to damage the boar's penis.

The sparse semen before and after semen collection and the colloid part should be discarded.

If it is found that the quality of the semen collected is not good, under the normal feeding conditions, the semen of the boar is examined every half a month, and then the decision is made after a month.

Make good semen collection records, carefully analyze and summarize semen quality and so on.

3. Semen examination and quality evaluation

The purpose of semen examination is to identify the quality of semen for further treatment or for fertilization and preservation. Examination should be carried out immediately after semen collection, which should be rapid, accurate, comprehensive, scientific and standardized. In actual production, it is not necessary to examine the semen of every boar, but the semen of the new boar should be examined for the first few times, and then every boar is tested every half a month.

① sensory examination

Ejaculation volume: usually, the ejaculation volume of a boar is 150 to 300 milliliters, but the range is generally 50 to 500 milliliters due to great differences in breed, age, sexual preparation, semen collection methods, technical level, semen collection frequency and nutritional status. Accordingly, semen can also be weighed (1 gram is equal to about 1 ml) to determine the amount of ejaculation. In general, when determining the ejaculation volume of boars, we should not only rely on the record of one ejaculation, but should take the average of the sum of multiple ejaculations in a certain period of time.

Color, smell: boar semen is light milky white or light grayish white, the thicker the milky white degree of semen, the more the number of sperm, such as abnormal color, should be checked for reproductive organ disease. Clean semen has only a little smell, such as contamination by the foreskin or semen quality changes, the smell is very strong.

PH value measured by ②

The PH value of pig semen is 7.3-7.9. The simplest method to determine the PH value is to use universal test paper to measure the PH value.

Examination of ③ activity

Motility test is an important item of semen quality test. motility is used to determine sperm motility, and motility test includes evaluating the proportion of sperm moving in a straight line. The method of operation is as follows: using a glass slide preheated to 35 ℃, sucking a drop of semen with an eyedropper, and then covering the liquid surface evenly with a cover slide, so that a clear picture of semen can be seen when examining this thin layer of sperm cells. Use a 100 or 400 times microscope to examine and evaluate sperm motility (as shown in the table below). If the motility is poor, the score is 0 or 1, and semen with a score of 0 or 1 should be discarded. In the actual operation, in order to ensure the accuracy of the determination and evaluation, it is generally necessary to repeat the check.

Sperm density can be measured by estimation method, sperm count method or light transmittance (turbidity) of sperm. The sperm density is roughly divided into "dense", "medium" and "thin" according to the density of sperm under the microscope, and briefly divided into "dense", "medium" and "sparse". Under microscopic examination, sperm is dense, and the distance between sperm is less than 1 sperm length, its density is "dense"; if the sperm can hold 1 or 2 sperm, it is "medium"; and the gap between sperm is large and can hold more than 2 sperm, it is "sparse". This kind of evaluation, like the evaluation of sperm motility, requires some experience in evaluation, but it is simple and easy to determine the dilution multiple. In addition, the sperm density can be measured accurately by colorimeter or spectrophotometer, but the equipment is expensive and the general production field is difficult to bear.

Examination of sperm morphology in ④

Whether the sperm morphology is normal or not is closely related to the conception rate. If the semen contains a large number of abnormal sperm, its fertilization ability is low. General good quality pig semen, its deformity rate should be less than 18%, ordinary quality semen sperm deformity rate should not exceed 20%, if more than 20% means poor semen quality, should be abandoned, not for insemination. "figure 4" is normal sperm morphology, and "figure 5" is some common abnormal sperm morphology.

⑤ other checks

It includes bacteriological examination, sperm staining smear, sperm survival time and so on, which can be selected according to the specific conditions and production scale of each production site.

4. Dilution and preservation of semen

After quality inspection of semen, semen should be diluted immediately in order to increase semen volume, to produce more semen head, and to provide a good nutritional environment for semen preservation.

Preparation of ① diluent

A variety of suitable diluents can be prepared, several of which are relatively complex and need to be prepared with the help of laboratory technology, which are generally only used in commercial artificial insemination stations. The diluents commonly used in production are those that are simple and only mixed once. You can buy the semen diluent powder that has been equipped and prepare it according to the instructions. For example, BTS, Guelph, Kiev, Merck, Zorpva, Reading, Modena and other diluents, some of them can be preserved for 3 days or 5-7 days. The following table lists some diluent formulations for your reference. When actually preparing the diluent, it should be noted that all kinds of compounds used must be "analytically pure", the distilled water added must be pure, and the double distilled water should be diluted if the conditions permit; all kinds of materials should be accurately weighed, and must be completely dissolved and fully mixed; the diluent had better be ready for use and should be used up within 24 hours at the longest.

Dilution of ② semen

The dilution of semen should be carried out according to a certain proportion according to the sperm density. If the sperm density is measured accurately, the dilution multiple is easy to calculate. However, in actual production, due to the consideration of input cost and many other factors, semen density can only be evaluated by "dense", "medium" and "sparse". When diluting semen in this case, the dilution ratio should be controlled at 1, 4, 4, 1, 10, preferably within 6 to 8 portions, that is, if you have 200ml semen, the diluted semen volume should not exceed 1000 ml. In addition, it is necessary to ensure that there are 1.5 × 109 sperm in one part of semen transfusion, and its capacity should be at least more than 50ml. It is best to ensure that the dilution multiple is within 8 parts, because the average sperm count of a normal boar at a time of ejaculation is 3040 × 109, with a range of 20,120 × 109. If the dilution multiple is controlled within 8 parts, it can still ensure that there are enough sperm to ensure energy.

If the sperm density has been measured accurately, it is easy to determine the dilution multiple. For example, if the semen density of a boar is 200 million / ml, the semen collection is 300ml, and the planned diluted semen density is 4 billion / 100ml, the boar semen can be diluted 300 × 2ppm 40cm 15 parts, that is, 1500~300=1200ml dilution is needed.

In the olefin release of semen, the most important thing is that the temperature of semen and diluent should be the same when mixing. The diluent is generally heated and maintained at 36 ℃ during the operation, and the isothermal 36 ℃ of semen and diluent is maintained as far as possible. If there is a temperature difference, it must be controlled within 1 ℃. When diluting, slowly pour the diluent into the semen and fully mix, the action should be light and slow, to prevent violent oscillation.

Preservation of ③ semen

The diluted semen should be kept in an incubator at a temperature of 17: 18 ℃ and gently shaken every 12 hours to prevent the diluent from precipitating. Never store semen in a refrigerator (2-8 ℃) or in an environment higher than 20 ℃ during production.

Operation technology of artificial insemination

Insemination is the last technical link of artificial insemination. Only when a certain amount of high quality semen is timely and accurately injected into the appropriate part of the reproductive tract of estrus sows can a good conception rate be obtained.

The insemination dose should not be too small. The normal dose of artificial insemination is generally 30 ~ 5 billion sperm / 1 dose, the volume is 80~100ML, and 3 billion / 80ML is generally used in the United States. The first share is about 4 billion / 100ML in our country. Toufen, however, this is mainly based on the actual situation, and is closely related to the variety, the technical level of insemination personnel and so on.

In the actual production, in order to improve the conception rate of pigs, two insemination is generally used, that is, after the first insemination, the insemination is repeated after an interval of 8 to 24 hours. For individual sows with a long duration of estrus, in addition to carefully observing the changes of their estrus symptoms and grasping the timing of insemination, they also use the method of multiple insemination, that is, insemination once a day for several days in a row, in order to increase their chances of conception.

Before insemination of sows, the diluted semen after preservation should also be examined. Only semen with a sperm motility of not less than 0.5 can be used for insemination, and the utensils used for insemination must be strictly cleaned and sterilized, from the treatment room to the production line, semen should be carried in an incubator to avoid stress and death of sperm caused by excessive or low external temperature. Before insemination, the vulva of sows should be cleaned and disinfected. The time of insemination is about 1930 hours after the beginning of estrus. In practice, the best time of insemination is in the estrus of sows. During insemination, first apply a little diluent to lubricate the vas deferens, then rotate upward and forward counterclockwise and insert them until they are locked in the cervix and cannot move forward, then pull a little outward slightly, and slowly pressurize the bottle of semen into the uterus, the length of insemination time should be similar to natural mating, about 5 minutes 15 minutes. After transfusion, slowly draw out the vas deferens and press the joint of the sow waist recommendation with the palm of the hand to prevent semen reflux.