Freemartinism: Rare condition that makes heifer twin useless

In rare occurrences, sometimes heifers give birth to twins. If the twins are both female, this is like a double blessing. If both are males, this is still good. But if the twins are heterosexual - male and female, the male is good but the female may be worthless, as it will suffer a condition known as freemartin. But why? 

What is a freemartin?

Freemartinism is one of the most commonly found intersex conditions in cattle. It may also occur in small ruminants like sheep and goats. It is a condition in dairy cattle farming that can result from twinning of a heifer calf with a bull calf. It affects the heifer twin, and is characterised by an underdeveloped reproductive tract. The condition arises when the blood supplies of the two placentas of the twins merge so that the calves share a common blood supply. Moreover, the hormone responsible for development of the male reproductive tract becomes active before those that regulate female reproductive tract. The male hormones can move via the shared blood supply to the female calf. The male hormone then interferes with the development of the ovaries, which in a normal calf will in future help in producing hormones that promote development of the rest of the female tract. In cattle, this condition is observed in 90 to 97 per cent of twin pregnancies. The male co-twin to freemartinism is usually fertile and normally developed. Freemartinism, nevertheless, does not occur in every heifer calf born as a twin to a bull calf. Approximately 10 per cent heifer twins are not affected. It is also possible for an apparently single born calf to be a freemartin, if the calf was a twin but the male died early in pregnancy.

.

Keep Reading

• Kenya spearheads Apple farming revolution in region
• Kenya spearheads Apple farming revolution in region
• Kenya spearheads Apple farming revolution in region

Clinical signs of a freemartin heifer?

The heifer develops just like a normal heifer but the signs become clear at puberty. She is that female that never comes on heat, is sterile, has an enlarged clitoris, a small vulva, anatomic continuity between the uterus and the vagina is frequently absent. Often the ovaries are underdeveloped and are not capable of producing eggs. The reproductive tract does not supply sufficient hormones necessary to maintain a pregnancy. Upon physical examination by a Vet, she is found to have a short vagina on rectal palpation and a prominent, male-like tuft of hair. The female's external genitalia appear normal very often. In cattle, twinning trend has a genetic background that has been associated to hormonal regulation in favour of double ovulations. If calf twins - male and female - are born, it is prudent to examine female's blood. The test is based on searching male's gene markers in female's body. Early diagnosis is recommended to avoid economic losses caused by useless therapeutical treatment.

Treatment options

There is no treatment for freemartinism. A female born with a male twin has no reproductive value, is sterile and should be identified as early as possible for culling.  Freemartinism cannot be prevented. When buying a heifer, ask if she was born with a male twin and if the answer is yet, involve a Vet to examine it.

[Dr Paul Kang’ethe, [email protected]]