Thirty Questions About Boar Semen, Authoritative Answers Worth Saving
Thirty Questions About Boar Semen (Highly Authoritative), Remember to Save After Reading!
The quality of boar semen is directly and closely tied to the conception rate during estrus and the number of piglets born, so no matter how much a pig farm emphasizes the importance of boar semen, it is never an exaggeration. The purpose of writing this article is mainly to correct some mistaken concepts. We know that only when high-quality sperm and eggs combine can new life be born, which is itself a miracle of nature, so everyone engaged in artificial insemination should have a sense of reverence for life, and I hope that after reading this article you will gain a better understanding of the artificial insemination process.
1. What is generally present in boar semen?
Boar semen is a suspension of sperm cells, secreted by the boar's reproductive organs including the accessory sex glands. The liquid portion of the suspension is called seminal plasma, which helps carry and protect the sperm cells. Boar semen also contains a large amount of gel.
2. How long does it generally take for boar sperm to be produced?
Producing one sperm cell takes about 5 weeks, plus another two weeks of in the epididymis, which is a very long, coiled tubular structure attached to the surface of the testis, where sperm slowly move, gradually mature and acquire potential fertilizing ability; the epididymis is also the main storage site for sperm. Therefore, the semen you collect on a given day was often produced 7 weeks earlier.
3. What does normal boar sperm look like under a microscope?
Normal boar sperm contains a head and a tail, somewhat like the tadpoles we see, and the entire sperm cell is covered by a membrane. The head contains genetic information (chromosomes). At the tip of the head is the acrosome. The acrosome is a sac-like structure surrounded by a unit membrane and is rich in enzymes. During fertilization, it helps the sperm penetrate the egg. The tail includes the neck, middle piece, principal piece and end piece. The middle piece is rich in mitochondria, where the energy needed for sperm motility is produced.
4. What are abnormal sperm?
There are several kinds of abnormal sperm. For example: head abnormalities (swollen head or abnormally shaped head, etc.), tail abnormalities (double tail, bent tail, coiled tail, etc.), acrosome defects (segmented, incomplete, etc.) and retained cytoplasmic droplets. Cytoplasmic droplets form during spermatogenesis and normally fall off once the sperm matures. Sometimes the cytoplasmic droplet does not fall off, and whether it remains proximal or distal depends on how close it is to the head.
5. How are abnormal sperm generally produced?
Some abnormalities arise during spermatogenesis, that is, during production within the testis; others arise while sperm pass through the epididymis, and still others may arise during or after ejaculation due to improper handling and storage. Different factors at each stage can cause sperm abnormalities. For example, if a boar has a fever (elevated body temperature), this may affect spermatogenesis. Changes in temperature, pH, or osmotic pressure during semen dilution can all cause sperm abnormalities.
6. What do abnormal sperm mean for artificial insemination?
Abnormal sperm are not capable of reproduction, although depending on the maturity of the sperm some abnormal sperm can still reproduce. Therefore, when counting sperm in semen, the percentage of abnormal sperm must be taken into account (up to 30%).
7. How big is boar sperm?
Normal sperm are about 45 micrometers (about 0.0045 cm). To give you a rough way to calculate it, if you line sperm cells head to tail in a chain, you can string 220 sperm cells into 1 cm.
8. Since sperm are so small, how do they reach the egg? Do sperm swim to the egg under their own power?
No! Considering that the sow's uterus has two uterine horns each 1.5 m long, it is impossible for such small sperm to swim the entire distance. During fertilization, it is mainly contractions of the sow's uterus that drive sperm rapidly to the site of fertilization (the place where sperm and egg meet). This is also why stimulating the sow during fertilization is important. Once sperm reach the fertilization site, the sperm's own motility then becomes important. Tail movement helps the sperm move to the egg and drives the sperm head into the egg.
9. About how many sperm can reach the fertilization site during each fertilization?
In fact, only a very small proportion of sperm can reach the fertilization site (possibly less than 1%). After fertilization, passing rapidly through the uterus, only about 10,000 sperm reach the sperm storage area of the oviduct - most sperm will suffer backflow during passage through the uterus, that is, flow out beyond the cervix, or be phagocytosed by the sow's somatic cells, which occurs when the sow's body is stimulated by foreign substances. When ovulation occurs, sperm are slowly released from the storage area and move toward the fertilization site, and during this process fewer than 100 sperm survive.
10. Is sperm motility related to fertility?
Research by Billy Flowers in North Carolina confirmed that when boar sperm motility exceeds 60%, fertility and litter size are no longer affected by sperm motility. Therefore, most companies set a target of over 70% for sperm motility.
11. Is there a single test that can accurately predict the fertility of semen ejaculated by an individual boar?
Unfortunately, no. At present, becausetechnologyhas shortcomings in operability and reliability of execution, we can only evaluate several components of sperm quality rather than all of them. But if that component is not a limiting factor, then there is no necessary connection between the aspects we can evaluate and fertility. For example, we can look at some components of sperm such as the tail or head and check whether their shape is normal, but we cannot guarantee that the sperm will therefore function normally, or assess whether the chromosomes are in good condition (genetic material). It is like a car: you can look at it and know whether the tires are intact or whether the shape is quite good. You can even try the lights to see whether they work normally, but when it comes to the engine or driving, you cannot be sure it will take you to your destination. But if you see that the car has no tires, then you can be certain that the car is no good. The same problem happens with sperm.
We can look at sperm and know whether that sperm is of poor quality, but we cannot be sure that such sperm are necessarily of high quality. We carefully observe the semen from each ejaculation before and after dilution to ensure that sperm motility and morphology are normal, so we can avoid using semen that appears to be of poor quality, but we cannot predict fertility based on semen quality.
12. How many sperm are contained in the semen ejaculated by a normal boar each time?
This is determined by several factors, such as the boar's age in days and the frequency of collection, and is generally between 20 and 60 billion.
13. What is in the insemination bottle?
Semen: sperm and seminal plasma
Aqueous mixture or extender: this can provide sperm with nutrients and metabolic support, protect sperm from changes in environmental temperature and pH, inhibit bacterial growth and increase semen volume to a dose capable of reproduction. It usually contains glucose, electrolytes, buffers and antibodies.
14. Are the sperm in the insemination bottle ready to combine with the egg?
No. Because they have not yet undergone a process called capacitation (in which sperm acquire the ability to fertilize), and capacitation usually takes 6-8 hours after sperm enter the sow's body.
15. How long can sperm survive inside the sow?
Usually, high-quality sperm can survive for about 24 hours in the sow's reproductive tract. Eggs can only survive 12 hours, so it is best that sperm have already reached the fertilization site before ovulation, and the sperm can only wait for the egg.
16. At what age in days do young boars begin to have semen collected?
Boars begin puberty at 5.5 months of age, and sperm can be found in their semen. Once a boar is physiologically mature and able to produce sufficient quantities of high-quality mature sperm, training the boar to mount the collection dummy can begin, at about 6-7 months of age. A boar does not truly reach physical maturity until 10 months of age.
17. How long is the storage period for sperm in the insemination bottle?
Usually 3-10 days, depending on the extender you use and whether the semen is stored properly. Generally speaking, with a certain extender, we guarantee a storage period of at least 5 days.
18. About how many sperm are in one insemination bottle? How do you know?
The goal of artificial insemination is: at least 2.3 billion sperm cells in each insemination bottle. To ensure this value is reached, the semen from each ejaculation is weighed and diluted according to sperm concentration. Boar studs place great importance on measuring the number of sperm in each semen collection so that the result is as accurate as possible and the mixing is thorough. Therefore, all insemination bottles contain an average of 2.3 billion sperm cells. ⟦45 19. Why do insemination bottles kept in a 17°C constant-temperature cabinet need to be shaken twice a day?
19. Why does the semen collection bottle need to be shaken twice a day when placed in a 17°C constant-temperature incubator?
If the insemination bottles are not shaken, sperm will settle to the bottom of the bottle. Therefore, shaking is needed so that sperm can obtain nutrients and metabolites and be redistributed in the extender.
20. Why should boar semen be kept away from sunlight?
Because ultraviolet light (UV) in sunlight can damage or kill sperm. This is why semen must be placed in a box during transport.
21. Why must semen be stored at 17°C? What does it mean if the temperature is higher or lower than this?
The ideal storage temperature for sperm is 17°C. If sperm are stored under high-temperature conditions, such as 20°C, sperm activity is not sufficiently inhibited (nutrient and energy use will be accelerated). Therefore, the vitality of the sperm will decrease. In addition, at higher temperatures there is also a risk of bacterial growth. If sperm are stored at 15°C, the sperm's protective membrane, including the acrosome, may be damaged (you may not observe this phenomenon during a simple check under the microscope, because under such conditions sperm motility may not be affected).
22. How is sperm morphology measured? How often does it need to be measured?
PIC stipulates that after each semen dilution, sperm morphology must be observed under the microscope, and a detailed analysis must be carried out every four weeks.
23. How does PIC ensure semen quality?
PIC has a strict quality control system, including compliance with the British Pig Executive (BPEX) protocol. We have our own quality control program, and in addition we send samples to an independent third-party laboratory for evaluation. A veterinarian from the independent laboratory inspects all populations once a week, assessing not only the health status of the boars but also whether the sperm meet high-quality standards.
24. How does PIC handle the process by which reserve breeding boars pass inspection to be used as breeding boars for commercial semen sales?
All new boars must pass strict quality control tests, including morphology, motility and the osmotic resistance test (ORT, a special test used to evaluate the integrity of the sperm membrane). Before reserve boars are used as breeding boars, they must have semen from multiple consecutive collections all pass testing.
25. Why is PIC GP semen colored?
Is this harmful to sperm? PIC uses some dyes in GP semen for easier identification. (These dyes, as well as some materials that come into contact with sperm, are non-toxic.) They come from reliable manufacturers, and in addition we conduct toxicity testing on every batch.
26. Is sperm sterile?
No! Sperm cannot be sterile; it may contain bacteria. Bacteria may come from the semen itself, from the sow, or from the environment. They are generally not pathogenic to sows, but if they are present in large numbers they may affect sperm quality. This is why most extenders contain antibiotics and why storage at 17°C is required, and why special care must be taken during collection and handling to ensure bacterial contamination is minimized.
27. How can I ensure that sperm will not transmit disease?
At PIC, we have many ways to ensure that sperm do not transmit disease. All boars from PIC farms must be strictly monitored under the PIC health program. Ensure that the number of sources for each population is minimized, and all sources must be PRRS (blue ear disease) negative farms.
Semen collectors must carry out clinical observation every day to ensure that all boars eat normally and appear in good condition.
Boar body temperature is measured once a day so that any potential problems can be detected in time.
All populations must obtain EU certification; undergo extensive serological testing, including for brucellosis, swine fever and pseudorabies. PRRS is monitored through regular serological testing (at least once a month) and semen PCR testing (at least twice a month). PCR testing is relatively expensive, but it has a special advantage: it can detect the virus in time (serology looks for antibodies, and the production of PRRS antibodies takes 10-14 days).
28. Can semen from different pigs be mixed?
Yes, it can, but in order to minimize health risks as much as possible, PIC decided not to do this. Therefore, the semen in your insemination bottle all comes from a single boar.
29. Why do we insist on using fresh semen rather than frozen semen?
Porcine frozen semen is actually feasible in terms oftechnology, but it is still not as effective as fresh semen; litter size and newborn piglet survival rate are usually relatively low; in addition, there is considerable individual variation, that is, the semen of some boars seems to be of higher quality than that of others. Also taking into account thetechnicallevel of most farms, frozen sementechnologyhas never been commercially applied. ⟦76 30. When is it estimated that sexed semen can be provided?
30. When is sexed semen estimated to become available?
Sexed semen has already become a reality in cattle production, but the production procedure is slow and costly. We consider that: compared with cows, sows require a larger volume of semen, so there may still be a long way to go before it can be converted into commercial production. But you can look forward to it!