A freemartin is a female bovine with a masculinized behavior and non-functioning ovaries. Genetically, the cow is female, but it is sterilized in utero by hormones from a male twin. Tribes Bovini Boselaphini Strepsicerotini The biological subfamily Bovinae includes a diverse group of about 24 medium-sized to large ungulates, including domestic cattle, bison, the Water Buffalo, the Yak, and the four-horned and spiral-horned antelopes. ...

Origin

The 18th-century physician John Hunter, discovered that a freemartin always has a male twin. In 1916, several researchers independently discovered what happens when the chorion (the outer layer of the two membranes that completely envelop a fetus) of a male and the chorion of a female bovine fetus fuse in the uterus. The blood vessels in the chorions become interconnected and male hormones pass from the male twin to the female twin. The male hormones then masculinize the female twin, and the result is a freemartin. (17th century - 18th century - 19th century - more centuries) As a means of recording the passage of time, the 18th century refers to the century that lasted from 1701 through 1800. ... Engraving of John Hunter (1728 – 1793) taken from the original portrait by Sir Joshua Reynolds, which is in the Royal College of Surgeons. ... 1916 (MCMXVI) is a leap year starting on Saturday (link will take you to calendar) // Events January-February January 1 -The first successful blood transfusion using blood that had been stored and cooled. ... Chorion can refer to the following things: Chorion is the outer membrane of the amniotic sac. ... Fetus at eight weeks Foetus redirects here. ... A hormone (from Greek horman - to set in motion) is a chemical messenger from one cell (or group of cells) to another. ...

Uses

Modern

Freemartins are occasionally used in stem cell and immunology research. During fetal development cells are exchanged between the fused circulations of the bovine twins. Up to 95% of the freemartin's blood cells can be derived from those of its twin brother. Bull-derived cells and their progeny can be easily visualized in the freemartin tissues, as only they contain the male Y chromosome. Thus, by analyzing these tissues, one is able to investigate the capacity of hematopoietic stem cells or other circulating cells to produce other tissues in addition to blood. The freemartin model allows one to analyze perfectly healthy and unmanipulated animals, without resorting to transplantation often used in stem cell research. Mouse embryonic stem cells. ... Immunology is a broad branch of biomedical science that covers the study of all aspects of the immune system in all organisms. ... The human Y chromosome is one of two sex chromosomes, it contains the genes that cause testis development, thus determining maleness. ... An organ transplant is the transplantation of an organ (or part of one) from one body to another, for the purpose of replacing the recipients damaged or failing organ with a working one from the donor. ...

If suspected, a test can be done to detect the presence of the male Y-chromosomes in some circulating white blood cells of the subject. Genetic testing for the Y-chromosome can be performed within days of birth and can aid in the early identification of a sterile female bovine.

Historical

Prior to the wide availability of inexpensive testing, freemartins were valued as a way to identify cows in estrus, without risking fertilization (as would occur if a bull were used). Once a freemartin attempted to mount a cow, that cow would then be isolated from the rest of the herd and allowed to breed with the desired bull or prevented from breeding, as desired. Estrus (also spelled œstrus) or heat in female mammals is the period of greatest female sexual responsiveness usually coinciding with ovulation. ... Categories: Biology stubs ... Breeding has several meanings related to procreation: In animal husbandry and in horticulture the selection of stock for propagation and the act of insemination by natural or artificial means is called breeding. ...

Other uses of the term

The term "freemartin" has occasionally been used to refer to lesbians. Lesbian describes a homosexual woman. ...

In the Aldous Huxley novel Brave New World, a freemartin (mentioned in chapters 1, 3, 11 and 17) is a woman who has been deliberately made sterile by exposure to hormones during fetal development; by government policy, freemartins form 70% of the female population. Aldous Leonard Huxley (July 26, 1894 – November 22, 1963) was a British writer who emigrated to the United States. ... Book cover of Brave New World. ...