History of Artificial Insemination

							History of Artificial Insemination
As we understand more about the physiological processes in the food producing animals, we become
capable of manipulating these animals to increase their productivity. As new technology develops in
agriculture, new industries also develop. The artificial insemination (AI) industry is a classic example. This
industry is the result of a quick application of science to agriculture. The primary reason for artificial
insemination, and hence this industry, is to speed up the rate of genetic improvement. This is accomplished
by greatly increasing the selection differential, wherein one highly selected sire is mated with thousands of
females.

Although the commercial use of artificial insemination is recent (1937), the sequence of events leading to
today’s industry traces back to the 17th century. It was in 1677 that Leeuwenhoek saw spermatozoa
through the newly discovered microscope and in 1780 when Spallanzani in Italy discovered that a dog
could be impregnated with the cellular portion of semen. He also observed that the spermatozoa could be
inactivated by cooling and reactivated later. About 1900, Professor Ivanov was hired by the Russian throne
to develop AI for horses. He was an ambitious man and by 1933 he had developed methods for collecting
semen and inseminating horses, cattle, sheep and swine. Most of these early inseminations were with sheep
and horses. A Dane by the name of Sorenson, who had studied in Russia, returned to Denmark and
established the first AI cooperative in 1933.

E.J. Perry, an extension dairyman from New Jersey, was in Denmark at this time. He returned in 1937 and
hired a Dane by the name of Larson to help establish the first AI cooperative in the United States.
Research with cattle AI had been in progress in the U.S. and by 1939 seven AI cooperatives had
developed. The number of AI organizations increased rapidly, as did the number of cows inseminated, the
number of breedings obtained from each male, and the conception rate. As competition between
organizations developed and costs increased, the small cooperatives consolidated, resulting in the large
cooperatives and companies that exist today.

Approximately 60% of the dairy cows in the U.S. are artificially inseminated. This is well below the use of
AI in European dairy areas such as Denmark, Holland and England where over 90% are artificially
inseminated. The two largest AI organizations are not cooperatives but privately owned companies with
nation and worldwide semen distribution. The largest of these, American Breeders Service Global
(DeForest, WI), sells approximately 3.5 million breeding services per year. The second largest is Select Sires
(Plain City, OH).

Although methods for collecting semen and insemination have been available for many years, it is likely
that the commercial industry would have developed as rapidly without certain significant research
discoveries: 1) the development of semen extenders which would protect sperm cells against temperature
shock and thereby allow cold storage, 2) the realization that bull semen could be extended to breed large
numbers of cows from each ejaculate and 3) the discovery of methods for frozen storage of bull
spermatozoa. In 1939, Drs. Phillips and Lardy at the University of Wisconsin discovered that egg yolk
would protect sperm cells from temperature shock upon cooling. The protection was due to phospholipids
and lipoproteins in the egg yolk. Extenders combining egg yolk with phosphate, citrate and bicarbonate
buffers were soon developed and they form the base for extenders in use today. Heated milk was also
found to be a satisfactory semen extender and provides temperature shock protection.

Spermatozoa were some of the first cells frozen; they were successfully frozen in England in 1949. Dr.
Polge and co-workers discovered that glycerol in the extender media would protect fowl and bull
spermatozoa from damage during freezing. Early freezing and storage was accomplished with dry ice and
alcohol at a temperature of -79º C. Later, liquid nitrogen was used as a coolant because its -196º C
temperature provided longer and safer storage conditions.

It is generally considered that cattle producers use AI in their herds because 1) it offers service to
genetically superior sires, 2) it allows the maintenance of a herd closed to new animals and thus provides
disease protection, 3) a dangerous bull need not be kept on the farm and 4) organized breeding
management and record services are provided. In swine AI is often used to decrease the cost of
maintaining males at the production unit. In turkey's AI is used because mating cannot occur naturally.

The methods are feasible but the use of artificial insemination is lower in species other than cattle either
for economic reasons or for horses the registry of offspring is restricted. Changes in industry structure
often drive changes in the use of AI however. For example in the swine industry the growth of large farm
units in the 1990's led to the adaptation of AI to reduce expenses of maintaining males. In horses the
change in the Quarter Horse Association to allow the registration of foal from AI with cooled and shipped
semen has increased the use of AI.

Questions: - answer on another sheet of paper

   1. What is the primary purpose of artificial insemination (AI)?

   2. When did commercial use of AI begin?            To what period of time can we trace the roots of AI?

   3. Who discovered that dogs could be inseminated by the cellular portion of AI and that semen could be
      inactivated by cooling, only to be reactivated later?

   4. What happened to the smaller cooperatives that were present when AI first became commercialized?

   5. What percent of cows are bred by AI?

   6. True or false: the two largest AI organizations are cooperatives

   7. List the three research discoveries that allowed the AI industry to develop rapidly.

   8. What is used as a coolant for semen and at what temperature is semen kept?

   9. What are four reasons that cattle producers use AI in their herds?

   10. Why is the use of AI lower in species other than cattle?