A Freemartin is an infertile female calf born as a twin to a male. Freemartins become infertile from being exposed to male hormones in the uterus.
About 90% of female calves with a male twin are Freemartins. They have both X and Y chromosomes in their blood, unlike normal heifers which have only X chromosomes.
Freemartins are easy to identify when their male twin is born alive. But occasionally the male twin dies during pregnancy or is stillborn and may be missed during the busy calving period.
That means you may end up spending time and money raising an infertile animal.
The larger your herd the more likely you are to have an unidentified Freemartin.
Gene test to identify Freemartins
Identify Freemartins with a DNA test to detect Y chromosomes in a calf’s blood.
If you suspect you have an affected animal, ask your vet to take a 10ml blood sample and send it to our laboratory in a purple top blood tube, along with a completed Individual Animal Submission Form — tick Freemartin to indicate the test you want.
You can also use the test to decide whether to cull a female calf with a male twin born to one of your top cows. There’s a 10% chance they won’t be a Freemartin — and worth keeping to protect your herd’s genetic value.
Individual Animal Submission Form
Getting the results
We’ll email the results to you four weeks after we receive the sample.
Find out more
Call our GeneMark Laboratory on 0800 436 362 to find out more about the Freemartin DNA test.