freemartin


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freemartin

(frē′mär′tn)
n.
A female animal, usually a calf, that is born as the twin of a male animal and is sterile because of having abnormal internal reproductive organs.

freemartin

a female twin born with a male, in which normal female sexual development has been adversely affected by hormones produced by the male twin.

freemartin

a sterile female born co-twin with a male. Occurs most commonly in cattle, very rarely in sheep, and apparently not at all in the other species. Male hormones produced by the male calf share the common circulation and inhibit the normal development of genitalia of the female. The female is also an erythrocytic chimera and can be diagnosed as a freemartin by this means. It can also be diagnosed by cytogenetic techniques. It produces white cells with XY as well as cells with XX chromosomes. Structural changes of nonpatent vagina, small vulva, cordlike uterus and hypoplastic ovaries are diagnostic but inconsistent. Some freemartins are quite normal clinically but all are sterile.
Enlarge picture
Freemartin placenta. By permission from Buergelt CD, Color Atlas of Reproductive Pathology of Domestic Animal, Mosby, 1996
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References in periodicals archive ?
Touching placentas will often form into one, ensuring a freemartin.
Feel around for an extra opening or protrusions; both indicate a freemartin.
If the tube doesn't slide in more than a couple of inches, you most likely have a freemartin.
Granted there's only an 8% chance that she's not a freemartin, but around here, the glass is always half-full of frothy whole milk, chilled to perfection--and there's always more where that came from.
Trouble with twins
Unfortunately, this concept runs into two problems: the low rate of multiple births and freemartins.
Due to freemartins, the practice of purchasing or retaining the female half of twins for breeding purposes should be avoided.
Multiple births in cattle aren't always desirable
Hence, they could not be freemartins, yet they inherited Y chromosome material from somewhere, most likely from their fathers.
Male chromosome hinders female cattle reproduction
The West Eugene club will mark the end of pre-Lenten hedonism with a party hosted by the Freemartins, Genus Pro and Papa's Soul Kitchen.
BRIEFLY
Hermaphrodites, freemartins, mosaics and chimeras in animals, Pp.
A Critical Approach to the Definition of Darwinian Units of Selection

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