Modern producers face a unique challenge to produce more food for a growing population while reducing their footprint on the environment. But efficiencies in breeding through research and technology have allowed farmers to up their production without increasing resources.
What is artificial insemination?
Artificial insemination (AI) is a breeding method that allows producers to make genetic choices at modest cost. Pigs are bred using semen samples instead of breeding physically with a boar. The majority (estimates are 90%) of breeding in the industry is conducted using AI.
“Many improvements in productivity and feed efficiency that the swine industry has gained can be attributed to artificial insemination,” says Trish Berger, UC Davis professor. “Before AI we were using the top 10% of animals to breed, but now we are using the top 1%. With AI, you can breed at least 10 times as many females from a single boar, and that’s a very conservative estimate.”
AI has brought modern conveniences to the industry that have enabled production to expand. AI allows producers to be selective, consistently breeding more efficient herds. Genetics play a role in growth performance, feed efficiency, reproduction productivity and meat quality.
Benefits of artificial insemination
- Decreased housing and feed costs: AI enables farms to create the same amount of meat by using fewer resources – improving resource management and a farm’s bottom line. In fact, it is estimated that one boar can easily inseminate 500 sows in a year with AI. Utilizing AI decreases the number of uncastrated boars that a farm needs to house. This is notable because boars that are not castrated are potentially more aggressive, and, therefore, must be housed separately.
Furthermore, boar taint affects meat quality, so boars are castrated within the first few weeks after birth to prevent taint. Having fewer boars on a farm decreases feed costs and opens up more space for sows and piglets. Typically, a farm keeps a few boars onsite to help detect estrus in sows, whether they use AI or manual breeding methods. - Worker safety: Boars can be aggressive and dangerous. AI prevents farm workers from needing to interact with boars during mating and reduces the number of boars on the farm to care for, therefore increasing worker safety.
Time savings: Breeding a gilt or sow physically with a boar may take 15 minutes. After a boar breeds a sow, it cannot breed another pig for 12-18 hours. Conversely, a single semen sample can be used to breed up to 15 females using AI, furthering the ability to breed with the best boars. Producers, especially those who synchronize their herds, can breed all sows in a couple of days, greatly improving breeding efficiency.
“Artificially inseminating a pig takes five to ten minutes, compared to supervising a boar which might take 15,” Berger says. “Sure, this doesn’t seem like that much time, but the boar can’t keep going, while the breeder can go down the line and breed every pig that’s in estrous. It’s much more efficient.”
Additives are often added to semen samples to extend their shelf life, allowing producers to store samples for up to seven to 10 days.
Heat stress reduction: Swine do not have functional sweat glands, which makes them susceptible to heat stress. Heat stress has adverse effects on swine production, especially among boars.
Evidence shows that heat stress in boars reduces sperm production and quality. While researchers are exploring ways to keep swine cool in hot months, AI reduces the possibility of heat stress and ensures a quality sperm sample because boars are kept cool when housed.
Boars used for semen samples are housed in air-controlled facilities, and semen samples are stored at the proper temperature. The increased access to overnight shipping allows U.S. producers to receive semen quickly and ensure it is temperature-controlled throughout the delivery process.
- Cleaning: Synchronizing the herd by weaning and inseminating at the same time enables producers to improve their farm sanitation, as sows will farrow at one time. AI enables producers to have an all-in-all-out cleaning approach, deep cleaning the farrowing and growing barns depending on where the herd is in the process. Deep cleaning is a good biosecurity practice to prevent disease in the herd and improve sanitation for farrowing sows.
Altering genetics by using artificial insemination
Beyond farm efficiencies, breeders can make genetically stronger pigs, as they can select the most efficient boar to breed with their sows. This reduces health issues and the risk of certain diseases. Breeders can continue to breed for top-performing traits to create the strongest herd possible.
“AI not only enables us to change genetics, but it lets us change genetics the way we want to change them,” Berger says. “As research advances, everyone can afford to take advantage of breeding the best possible herds.”
Altering genetics creates an opportunity to improve piglet strength and health, a crucial period for pig success. Mark Knauer, associate professor and Extension swine specialist, and his research team at North Carolina State University, have conducted research to show that altering genetics to increase functional teats betters piglet survival.
Teats provide piglets with food through milk but also produce colostrum, a foundational nutrient source for young pigs. By increasing functional teat count, piglets face less competition for food and have greater access to colostrum, increasing their chance of survival.
“Some of the underlying biology behind increasing functional teats is the need for colostrum for piglet survival,” Knauer says. “When you have more functional teats on a sow, it appears you increase the available colostrum for the piglets, and you also reduce competition in colostrum consumption between piglets. That combination seems to enhance piglet survival. Genetic companies are improving functional teats but not as fast as litter size, so our research addresses that and emphasizes the need for improvement to increase piglet survival.”
Experts see opportunities to continue genetic research that can be applied broadly in swine production. AI creates accessibility to these advantageous genetic alterations quickly and enables them to be applied on a broad scale in a herd.
“We have the ability to research genetic selection lines, and that’s unique, there’s not that many locations in the world with that capability,” Knauer says. “Basically, we can create lines of pigs by selecting for a single trait, and that way we can get an idea of what’s going right and not going right, looking at the underlying biology.”
Insemination process
AI is a simple practice that can be taught to producers and farm staff.
“If you visited me and we had a few gilts in heat, I could teach you how to artificially inseminate in an hour,” Berger says. “And you’d be pretty good at it.”
The first step in inseminating is identifying when a sow is in “heat,” which indicates they are in their fertile window. The reproduction cycle (called estrous) is a 21-day time period. The estrus phase is two to three days and the opportunity to inseminate a gilt or sow. It can be detected by farm staff checking for signs, such as standing still when pressure is applied to pigs’ backs, among other indications. Once estrus is detected, the pig should be inseminated once every 12-24 hours for two days.
The supplies needed for insemination are minimal and include:
- Semen sample
- An AI breeding rod or catheter
- Non-spermicidal lubricant
- Scissors
- Damp towel
- Mature boar or boar spray
The breeding rod is inserted into the pig until it “locks” into place in the cervix. Once the rod is locked, the semen bottle is inserted into the breeding rod and the pig will begin to capture the semen. It should take between five and ten minutes for the pig to finish breeding. During this time, the pig pulls the semen into the uterus. Applying pressure to the sow’s back may assist in this process. When the sow is done, the sow will “unlock” the breeding rod.
A new breeding rod should be used for each consecutive insemination.
Proper sample handling
It is crucial to keep samples at the appropriate temperature to maintain quality. Sperm can be collected on a farm by a producer or can be purchased from a third-party vendor and shipped to a producer. Samples purchased from producers integrate possible genetic improvements.
“Overnight shipping has been instrumental in being able to ramp up artificial insemination,” said Dr. Berger. “Before we were trailing behind European countries who could get from one place to another in a day, now we can make that happen and keep the samples at a safe temperature.”
Samples should be kept at 60° to 65° F and should always be handled with sterile materials; they should not be kept below this temperature and should never be frozen. Additionally, they should not be exposed to direct sunlight.
Farm staff should rotate samples gently once to twice daily to keep them viable; they should never be shaken.
The bottom line
AI is one tool in a producer’s toolkit to improve efficiencies in operations to create more meat with fewer resources. As research in genetic altering continues, producers will breed herds that continue to feed the population and reduce their environmental impact.
