Artificial insemination

From Freepedia

Artificial insemination (AI) is when sperm is placed into a female's ovarian follicle (intrafollicular), uterus (intrauterine), cervix (intracervical), or fallopian tubes (intratubal) using artificial means rather than by natural copulation. Modern techniques for artificial insemination were first developed for the dairy cattle industry to allow many cows to be impregnated with the sperm of a bull with traits for improved milk production.

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Artificial Insemination for Animals

Artificial insemination is used in animals to propagate desirable characteristics of one male to many females or overcome breeding problems, particularly in the cases of horses, cattle, swine pedigreed dogs, and honeybees. Semen is collected, frozen, and shipped to the female's location. These are referred to as "straws". To allow the sperm to remain viable during the time before and after it is frozen, the semen is mixed in with a solution containing glycerol. An "extender" is a solution that allows the semen from a donor to impregnate more females by making insemination possible with fewer sperm. Antibiotics, such as streptomycin, are sometimes added to the sperm to control some venereal diseases.


Artificial insemination of farm animals is not uncommon, especially for breeding dairy cattle. It provides an economical means for a livestock grower to breed their herds with males having very desirable traits.

Human Artificial Insemination

In humans artificial insemination is usually part of an infertility treatment; either the woman's partner's sperm (artificial insemination by husband, AIH) or donor sperm (artificial insemination by donor, AID) can be used.

In its simplest form, the woman's menstrual cycle is closely observed and, just when an ovum is released, semen from a donor is placed in her upper vagina. If the procedure is successful, she conceives and bears to term a baby as normal, making her both the genetic and gestational mother. AI is essentially low-tech, and in the days before AIDS became a high-profile killer, many lesbians in the West bore babies this way, with a little help from their friends. Even now, the main purpose of the clinics is to freeze, store, and defrost the sperm, to check the donors' health, and to draw up legal contracts.

Of course, there are various gradations of treatment, and more technical procedures are sometimes needed. For example, semen can be injected directly into a woman's uterus to improve the chance of conception in a process called intrauterine insemination.

Artificial insemination has become a significant issue in recent years, particularly in debates revolving around surrogate parenting. Legal issues have arisen in cases where the gestational (and possibly genetic) mother decides to keep the child. Likewise, there have been debates over the rights of sperm donors. There have also been debates as to whether conceiving a baby without sexual intercourse is ethical.


History

Many people think of artificial insemination as a modern technology but it has a long history. Thus, apparently artificial insemination was attempted on Juana, wife of King Henry IV of Castile. In 1677 the Dutch scientist Leeuwenhoek saw spermatozoa through the newly invented microscope. More than 100 years later in 1780 an Italian priest and physiologist named Lazzaro Spallanzani performed an experiment in his laboratory that revolutionized the way scientists thought. Until this point scientists had a very primitive understanding of conception largely based on how plants grew. They speculated that the embryo was the "product of male seed, nurtured in the soil of the female." Spallanzani's experiment on dogs proved for the first time that there must be physical contact between the egg and sperm for an embryo to develop. With this new knowledge Spallanzani experimented on frogs, fish, other animals and was successful.

Efforts to develop practical methods for AI were started in Russia in 1899. Papers on artifical insemination in horses had been published by 1922. By the mid 1940's artificial insemination had become an established industry. In 1949 improved methods of freezing and thawing sperm were developed. The idea for adding antibiotics to the sperm solution came in 1950 from Cornell. Improved methods of sperm collection were developed in the 1970's and 1980's. Research to improve methods of artificial insemination continues and is usually studied under animal science curriculums.

See also

External links

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