GREENWICH, N.Y. — AI is in the news often these days as the growth and improvement of artificial intelligence has brought debate about its ramifications. However, there is another AI that is more familiar to those in the farming community: artificial insemination. Artificial insemination has become a common practice in certain livestock industries in the past century.
Artificial Insemination is a method of breeding livestock that involves manually implanting the semen of a male into a female that is in heat. This process is done to obtain a desired trait in offspring and improve the genetics of a herd. The beginning of artificial insemination is often placed with the discovery of sperm by the Dutch scientist Antonie van Leeuwenhoek and his assistant Johannes Hamm in 1678. Leeuwenhoek and Hamm called the sperm “animalcules” and were able to view them thanks to Leeuwenhoek’s superior microscope lens crafting skills.
A little over a century passed before the first successful artificial insemination was accomplished by the Italian scientist Lazzaro Spallanzani. In 1784 Spallanzani performed an artificial insemination in a dog which birthed three puppies. Spallanzani is also credited with uncovering the effect of cooling on sperm when he noted that sperm became motionless after placing them in snow, but then regained motion when warmed up again.
Advancements in the field of artificial insemination started to ramp up around the turn of the 20th century. In 1897 University of Cambridge biologist Walter Heape conducted AI studies in rabbits, dogs, and horses. Heape also began to uncover the relationship between seasonality and reproduction. Starting in 1899 the Russian scientist Ilya Ivanov began studying AI in various farm animals. Ivanov became the first to artificially inseminate cattle and he pioneered stallion selection for the use of AI in horse breeding. Through Ivanov’s work Russia became a center for AI study leading to further development in the field in other parts of the world. Learning from Ivanov, Japanese researchers conducted successful AI programs in the 1910s. Their findings would not be known to Western countries until the late 1950s.
By the 1930s AI breeding was happening on a large scale in Russia with nearly 20,000 cattle bred by the technique in 1931. Towards the end of the decade in 1938 the Russian programs successfully bred 1.2 million cows, 40,000 mares, and 15 million sheep by artificial insemination. Ivanov’s successor, Victor Miroslav continued to improve the field operating large breeding projects and designing the first artificial vagina for bull, ram, and stallion semen collecting. Miroslav’s design is still the basis for apparatuses used for semen collection today.
AI made its way to the United States in the early 20th century. In 1907 a Hereford calf was born to a herd in Alva, Oklahoma by means of AI, but it was seldom used through the 1930s. Back in Europe, the Danish veterinarian Eduard Sørensen and a team of scientists organized the first cooperative AI organization for dairy cattle in Denmark in 1936. The program enlisted 1,070 cows and in its first year had a 59% conception rate. This was better than the natural conception services used in the same herd. Sørensen and his team also developed the method of rectovaginal fixation of the cervix. This method allowed semen to be inserted deep into the cervix or into the uterus allowing fewer sperm to be needed for insemination. The method remains standard today.
Seeing the success of the Danish project, the first U.S. AI cooperative, named Cooperative Artificial Breeding Association No.1, Inc., was established in 1938 by Rutgers University researcher Enos Perry. Cooperatives were also opened in New York and Missouri that same year.
The early days of commercial AI were more local in scope due to the short lifespan of semen. Semen would be mixed with a media, sealed in a glass ampule, and transported in an ice bath. This process allowed the semen to last 2-5 days. Within this timespan a farmer could choose which semen he wanted to use in his herd and the insemination would be performed by a veterinarian or AI technician. In many cases the hardest part of the procedure was catching the cow that was in heat so that the breeding could be performed.
In the 1940s &1950s work was done to improve the longevity of semen. In 1940 an egg yolk-based medium was found to protect sperm when it was cooled ensuring the potency of the semen. A bit later adding sodium nitrate to the concoction enabled semen to be transported further. In 1950 researchers at Cornell University added antibiotics to the solution adding further benefits. The “Cornell Extender” as it came to be known became the standard solution to preserve and prevent the contamination of semen.
Another development in the extension of AI work was the switch from glass vials to straws. Semen was eventually able to be stored by freezing. However, the glass containers could not always handle the cold temperatures (-79 degrees Celsius) at which the semen was stored. Sørensen and the Danish researchers are credited with coming up with the straw for packaging, storing, and transporting semen. A story goes that the idea was partially inspired after Sørensen saw kids sipping drinks with straws at a birthday party his daughter was attending. The technology was later improved on in the 1960s by the French scientist Robert Cassou. These improvements coupled with the earlier switch from freezing in solid carbon dioxide to liquid nitrogen (at temperatures of -196 degrees Celsius) helped semen better survive freezing and thawing leading to better conception rates by the 1970s.
In 1946 84 cattle insemination associations existed in the United States and by 1955 30% of registered U.S. dairy cows were inseminated by frozen semen. Artificial insemination mainly took hold in the dairy industry due to bovine semen’s ability to freeze, and the ability to instill desired traits, such as better milk production, into dairy herds. Other factors included safety, since farmers would not have to handle dangerous bulls as much, and efficiency, since dairy cows were already highly managed and AI could more easily be worked into a cow’s program.
The latter decades of the 20th century and recent years brought more advancements to AI including sexed semen to ensure the desired gender of offspring and estrus synchronization which makes animals in a herd go into heat at the same time making for more efficient breeding. Today, AI is still most often associated with the dairy industry and around 60% of U.S. dairy cows are bred via AI. Only around 5% of U.S. beef cows are bred using AI as range and pasture settings make using AI for beef more difficult. The use of AI is also common in the swine industry and in the horse industry mainly for breeding race horses. Other livestock such as sheep and poultry do not use AI as much due to anatomical and economic reasons specific to those species.
Chandler Hansen grew up and lives in Easton, NY. He is a graduate of Gordon College where he earned a bachelor’s degree in History. He serves as a writer and editor for Morning Ag Clips.