A freemartin or free-martin (sometimes martin heifer) is an infertile female mammal with Freemartinism is the normal outcome of mixed-sex twins in all cattle species that have been studied, and it also occurs occasionally in other mammals. J Am Vet Med Assoc. May 15;(10) Diagnosis of freemartinism in cattle: the need for clinical and cytogenic evaluation. Zhang T(1), Buoen LC. Freemartinism is recognized as one of the most severe forms of sexual abnormality among cattle. This condition causes infertility in the female.

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This causes exchange of blood and antigens carrying characteristics that are unique to each frewmartinism and bulls. A freemartin is the normal outcome of mixed twins in all cattle species which have been studied. From Wikipedia, the free encyclopedia. Reduced fertility sometimes occurs in the male twin, but in ninety percent of the cases the female twin is completely infertile.

The exchange of fluid and blood between the two calves mixes the antigens responsible for carrying the unique sex characteristics of each calf. The exact cause is not fully understood.

Six hundred calves This information published to the web on March 19, How does this occur? The twins develop with some sex characteristics of both the male and female. The fetus is genetically female, but male hormones dominate its reproductive system. Lilliewho published it in Science in The external vulvar region can range from a very normal looking female to a female that appears to be male.


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.

Diagnosis of freemartinism in cattle: the need for clinical and cytogenic evaluation.

Tandler and Keller vs. Freemartinism occurs when a female twin shares the uterus with a male. Approximately one-half of the sets of twins should contain both a bull and a heifer calf. Testicle size is associated with fertility, so there may be some reduction in bull fertility. The result was published in by Tandler and Keller. Journal of Dairy Science. Frewmartinism testing for the Y-chromosome can be performed within days of birth and can aid in the early identification of a sterile female bovine.

Can freemartinism be seen externally?

Often the ovaries are underdeveloped and are not capable of producing eggs. 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. Philosophical Transactions of the Royal Society of London. What are the economic implications? Usually, the vulva is normal except that in some animals an enlarged clitoris and large tufts of vulvar hair exist. A freemartin is genetically female, but has many characteristics of a male.

One fresmartinism Gilmore puts the percentage at about. Most often the external genitalia of the female appears normal, but the internal organs are underdeveloped.

In some cases, there are no symptoms of freemartinism because the male twin may have been aborted at an earlier stage of gestation. Freemartinism cannot be prevented. We propose that obvious freemartins be identified by use of the vaginal-length catt,e and that the remaining clinically questionable calves be differentiated cytogenetically.


General and Comparative Endocrinology.


By using this site, you agree to im Terms of Use and Privacy Policy. 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. Although the male twin in this case is only affected by reduced fertility, in over ninety percent of the cases, the female twin is completely infertile. For example the vulva may be normal, but there may be large amounts of hair present or the udder will not be fully developed and sometimes it is not noticeable at first glance.

Therefore, probably freemartiinsm large number of female co-twins that are not truly freemartins are sold to slaughter every year.

Diagnosis of freemartinism in cattle: the need for clinical and cytogenic evaluation.

About About 5m Publishing Our Editors. Dattle female twin born with a male twin has no reproductive value, it is important not to spend time and money preparing the heifer to go into your breeding herd. A total of blood samples from female calves born co-twin to male calves were examined cytogenetically for freemartinism between and Journal of Agricultural Research.