30 questions about Boar semen

MeritxellDonadeu Ph.D. in Veterinary Internal Medicine, Master of Science-Western European PIC Veterinary Manager-this article answered 30 major questions about boar semen. 1. What's in pig semen? Boar semen is a sperm cell suspension secreted by the reproductive organs of boars, including accessory glands. The liquid part of the suspension, called seminal plasma, helps to carry and protect sperm cells. Boar semen also contains a lot of gel. two。 How long does it take for boar sperm to produce? It takes about five weeks to produce a sperm cell, plus two weeks to stay in the epididymis. "the epididymis is a long, swirling tube attached to the upper surface of the testis, where the sperm moves slowly, gradually matures and acquires potential fertilization capacity, and the epididymis is also the main storage place for sperm." It must be noted that semen collected on the same day was generated 7 weeks ago. 3. What does the sperm of a normal boar look like? Normal sperm contains a head and a tail, and the whole sperm cell is covered with a diaphragm. The head contains genetic information (chromosomes). At the top of the head is the acrosome. The acrosome is a cystic structure surrounded by a unit membrane, which is rich in enzymes. In the process of fertilization, it can help sperm pierce the egg. The tail contains the neck, middle, base and tail. The middle is rich in mitochondria, which produce the energy needed for sperm movement. 4. Which are abnormal sperm? There are several kinds of abnormal sperm. For example, head deformities (fat head or shape deformities, etc.), tail deformities (double tails, curved tails, curly tails, etc.), acrosome defects (segmented, incomplete, etc.) and residual cytoplasmic droplets. Cytoplasmic droplets are formed during spermatogenesis and fall off after sperm maturation. Sometimes the cytoplasmic droplet does not fall off and remains at the proximal or distal end depending on its distance from the head. 5. How is malformed sperm produced? Some deformities occur during spermatogenesis-that is, during testicular production-some are produced as sperm pass through the epididymis, and some may occur during or after ejaculation due to improper handling and storage. Different factors at each stage can lead to sperm deformities. For example, if a boar has a fever (elevated body temperature), this may affect spermatogenesis. Changes in temperature, pH or osmotic pressure during sperm dilution can lead to sperm deformities. 6. What does sperm deformity mean? Most malformed sperm do not have the ability to reproduce, although some malformed sperm can reproduce according to the maturity of the sperm. Therefore, the sperm count in semen must take into account the percentage of malformed sperm (up to 30%). 7. How big is the sperm of a boar? Normal sperm is about 45 μ m (about 0.0045cm). To give you a way, if you connect sperm cells end to end to form a string, you can string 220sperm cells into 1cm. 8. Since the sperm is so small, how does it reach the egg? Does the sperm test its own motility to swim to the egg? No! Considering that the uterus has two uterine horns 1.5 meters long (see figure 3), it is impossible for such a small sperm to swim the whole journey. In the process of fertilization, it is mainly uterine contraction that causes the sperm to quickly reach the fertilization site (the place where the sperm and the egg meet). This is why it is important to stimulate sows during fertilization. Once the sperm arrives at the fertilization site, the sperm's self-motivation is very important. Tail movement helps the sperm move to the egg and pushes the sperm's head into the egg. 9. How many sperm can reach the fertilization site? Only a small part of the sperm can reach the fertilization site (less than 1%). After fertilization, it passes quickly through the uterus, and only 10000 sperm reach the sperm storage part of the fallopian tube-most of which are countercurrent during the passage through the uterus, that is, they flow out of the cervix or are swallowed by sow somatic cells. This phagocytosis occurs when the sow body is stimulated by foreign matter. When ovulation occurs, sperm are slowly released from the storage area and move toward the fertilization site, in which fewer than 100 sperm survive. 10. Is sperm motility related to fecundity? BillyFlowers's study in North Carolina confirmed that when boar sperm motility exceeds 60%, fecundity and litter size are no longer affected by sperm motility. As a result, PIC has set a target of more than 70 per cent for sperm motility. 11. Is there a single experiment that can accurately predict the fecundity of ejaculated semen from a single boar? Unfortunately, no. At present, because of the deficiency in the maneuverability of the technology and the credibility of implementation, we can only evaluate several components of sperm quality, not all. However, if that component is not a limiting factor, then there is no necessary link between several aspects that we can assess and fecundity. For example, we can look at some components of sperm, such as the tail or head, to see if they are in normal shape, but we cannot guarantee that the sperm will function properly, or assess whether the chromosomes are in good condition. Imagine a car. You can observe it and know if the tires are in good condition or in good shape. You can even try the headlights to see if they are working properly, but if you turn to the engine or drive, you can't be sure that it will take you to your destination. But if you see that the car has no tires, then you can be sure that the car is not good. That's what happens to sperm today. We can see that the sperm knows whether the quality of the sperm is poor, but we cannot guarantee that such sperm must be of high quality. At PIC, we carefully observe each ejaculated semen before and after dilution to ensure that the sperm movement and morphology are normal, so that we can avoid using semen of poor quality, but we cannot predict fecundity based on semen quality. twelve。 How many sperm are there in the semen of a boar each time? This is determined by several factors, such as age, and the frequency of semen collection is generally between 200 and 60 billion. 13. What's in the insemination bottle? Semen: a mixture or diluent of sperm and seminal plasma water: this provides sperm nutrition and metabolic support, protects sperm from changes in ambient temperature and pH, inhibits bacterial growth and increases semen volume to a dose that can reproduce. It usually contains glucose, electrolytes, buffers and antibodies. 14. Is the sperm in the insemination bottle ready to combine with the egg? No. Because it has not yet gone through a process called activation (the ability of sperm to gain fertilization), activation usually takes 6-8 hours for sperm to enter the sow. 15. How long can sperm survive in sows? Usually, high-quality sperm can survive in the breeding site of sows for about 24 hours. The egg can only survive for 12 hours, so it is best to have the sperm reach the fertilization site before ovulation. 16. At what age do young boars begin to collect semen? Puberty of boars begins at the age of 5.5 months, and sperm can be found in their semen. Once the sows are physiologically mature and can produce enough high-quality mature sperm, they can begin to train boars on the shelves, about 6-7 months old. 17. How long is the preservation period of sperm in the insemination bottle? It usually lasts for 3-10 days, depending on the diluent used and whether the semen is properly stored. At PIC, we guarantee a shelf life of at least 5 days through some kind of diluent. 18. How many sperm are there in the insemination bottle? How did PIC know that? PIC's goal is to have 2.3 billion sperm cells in each bottle. To ensure that this value is reached, each ejaculated semen is measured and diluted according to sperm concentration. At PIC, we attach great importance to measuring the number of sperm in each semen to make the results as accurate as possible and fully mixed. As a result, there are an average of 2.3 billion sperm cells in all semen bottles. 19. Why do you need to shake the bottle twice a day? If the bottle is not shaken, the sperm will precipitate at the bottom of the bottle. Therefore, it is necessary to shake so that the sperm can obtain nutrients and metabolites and redistribute them in the diluent. 20. Why do I need to keep the diluent away from the sun? Ultraviolet light (UV) in sunlight can damage or kill sperm. This is why semen must be placed in a box during transportation. 21. Why should semen be preserved at 17 ℃? What does it mean to be above or below this temperature? The ideal sperm storage temperature is 17 ℃. If sperm are stored at high temperatures, such as 20 ℃, sperm activity is not sufficiently inhibited (accelerating the use of nutrients and energy). As a result, the vitality of sperm will be reduced. In addition, there is a risk of bacterial breeding when the temperature is high. If the sperm is stored at 15 ℃, the protective membrane of the sperm, including the acrosome, may be damaged (you may not see this when you simply examine it under a microscope, because in this case, the movement of the sperm may not be affected. ) 22. How to measure the morphology of sperm? How often is it measured? In PIC, after each semen dilution, the morphology of the sperm must be observed under a microscope and analyzed in detail every four weeks. How does 23.PIC ensure semen quality? We have a strict quality control system, including compliance with the British Pig Commission (BPEX) draft. We have our own quality control program. in addition, we send the samples to a third-party independent laboratory for evaluation. Veterinarians in independent laboratories inspect all populations once a week to assess not only the health of boars, but also whether sperm meet high quality standards. 24. Back-up boars are tested as breeding boars for commercial semen sales. How is PIC operated? All new boars have to pass rigorous quality control tests, including morphology, motility and osmotic resistance tests (ORT, a special test used to assess the integrity of sperm membranes). Before reserve boars can be used as breeding boars, they must have all the semen produced several times in a row and pass the test. 25. Why does PICGP sperm have color? Is this bad for sperm? We are using some dyes in GP semen to make it easier to distinguish. These dyes and some materials that come into contact with sperm are non-toxic. They come from reliable manufacturers, and in addition, we conduct toxicity tests for each batch. twenty-six。 Is sperm sterile? No! Sperm is not sterile, it may contain bacteria. Bacteria may come from semen itself, sows, or from the environment. They are generally not pathogenic to sows, but if they exist in large numbers, they may affect sperm quality. This is why most diluents contain antibodies and require storage at 17 °C, and special care must be taken during collection and handling to minimize bacterial contamination. twenty-seven。 How can I make sure that PIC sperm doesn't spread the disease? At PIC, there are many ways to ensure that sperm do not spread disease. All boars from PIC Farm must be strictly monitored by the PIC Health Program. Ensure that the number of sources of each population is minimal and that all sources must be PRRS (blue ear disease) negative. Every day, workers must conduct clinical observation to ensure that all boars are fed normally and in good appearance. Take the boar's temperature once a day to detect any potential problems in time. All populations must be recognized by the European Union; they must undergo extensive serological tests, including brucellosis, classical swine fever and pseudorabies. PRRS is monitored through regular serological tests (at least once a month) and semen PCR tests (at least twice a month). PCR testing is expensive, but it has special advantages. It can find the virus in time (serology looks for antibodies, which takes 10-14 days to produce. ) 28. Can you mix the semen of different pigs? Yes, you can, but in order to minimize any possible health risks, PIC decided not to do so. So all the semen in your bottle comes from a single boar. twenty-nine。 Why do we use fresh semen and unfrozen semen? Frozen pig semen is technically feasible, but the result is not as good as fresh semen; litter size and survival rate of newborn piglets are usually low; there seem to be large individual differences, that is, the semen quality of some boars seems to be higher than that of other boars. In addition, taking into account the technical level of the farm, so frozen semen technology has not been applied commercially. thirty。 When will sex-specific semen be available? Sex-specific semen has become a reality in cattle production, but the production process is slow and expensive. If we consider that sows need more semen than cows, it will take a long way to convert to commercial production.