A bovine freemartin is usually defined as a sterile female calf, born co-twin with a citogenético y anatomopatológico del síndrome freemartin en bovinos (Bos. 3 days ago The freemartin phenotype appears in a dizygotic twin pregnancy citogenético y anatomopatológico del síndrome freemartin en bovinos (Bos. PDF | The freemartin condition represents the most frequent form of intersexuality found in cattle, and occasionally other species. This review.
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A freemartin or free-martin sometimes martin heifer is an infertile female mammal with masculinized behavior and non-functioning ovaries.
The animal originates as a female XXbut acquires the male XY component in utero by exchange of some cellular material from a male twin, via vascular connections between placentas: Freemartins are known to have been described by the Roman writer Varrowho called them “taura”.
The 18th-century physician John Hunter discovered that a freemartin always has a male twin. It was hypothesized early in the 20th century that masculinizing factors travel from the male twin to the female twin through the vascular connections of the placenta because of the vascular fusion, and thereby affect the internal anatomy of the female. Several researchers made the discovery that a freemartin results when a female fetus has its chorion fuse in the uterus with that of a male twin.
The result was published in by Tandler and Keller. Lilliewho published it in Science in In rural areas folklore often claimed this condition was not just peculiar to cattle, but extended also to human twins; this belief perpetuated for generations, as was mentioned in the writings of Bede.
The etymology of the term “freemartin” is uncertain: In most cattle twins, the blood vessels in the chorions become interconnected, creating a shared circulation for both twins.
If both fetuses are the same sex this is of no significance, but if they are different, male hormones pass from the male twin bovinow the female twin.
The male twin is largely unaffected by the fusion, although the size of the testicles may be slightly reduced. Testicle size is associated with fertility, so there may be some reduction in bull fertility.
Freemartins behave and grow in a similar way to castrated male cattle steers. 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 bovlnos early identification of a sterile female bovine.
Physical examination of the calf may also reveal differences: Also, many but not allfreemartins have a shortened vagina compared with that of a fertile heifer.
A freemartin is the normal outcome of mixed twins in all cattle species which have been studied. It does not normally occur in most other mammals, though it has been recorded in sheep goats pigs deer, and camels. Freemartins are occasionally used in stem cell and immunology research.
Male-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 can 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. From Wikipedia, the free encyclopedia. General and Comparative Endocrinology.
Journal of Agricultural Research. Philosophical Transactions of the Royal Society of London. An introduction to behavioral endocrinology. Tandler and Keller vs. Lillie and the question of priority”. Journal of Experimental Zoology Part B: Molecular and Developmental Evolution.
FREEMARTINISMO EM BOVINOS by Michelle Pereira Tavares Moreira on Prezi
Journal of Dairy Science. New Zealand Veterinary Journal. Retrieved from ” https: Bovine health Twin Sex. All pages needing factual verification Wikipedia articles needing factual verification from May Views Read Edit View history.