Twins from two fathers – now a reality?

When you see this cow with her two calves, you can hardly believe they are really twins, as they look so different. And yet, the suckler cow farmer can testify that the grey cow "Leni" gave birth to both calves.

Suckler cow Leni with her two calves shortly after birth. Licking the calves stimulates the circulation and promotes the bond between cow and calf.  (Photo : Dario Barelli) 

How does it come about that one calf seems to be descended from a red and white spotted Simmental bull and one from a black Angus bull? The answer is artificial insemination and "Silian".

Artificial insemination means that the cow is not covered by a bull via so-called natural semen, but that the cow is inseminated by an insemination technician or a veterinarian. For this purpose, semen is collected from bulls, prepared and kept frozen until use. During insemination, the semen is injected directly into the uterus. 

To inseminate a cow, an insemination syringe is inserted through the vagina and cervix so that semen can be injected directly into the uterus. (Source: www.agrarheute.com)

The second part of the riddle solution is called "SILIAN" - the name of the fathers of the two twin calves. "SILIAN" is the name of a semen box containing a mixture of sperm from three bulls of different breeds of cattle: SImmental, LImousin and ANgus. This sperm mixture is often used in insemination because the probability of pregnancy of the cows increases significantly. Why this is so is a matter of scientific puzzlement. For the time being, it remains a beautiful secret of nature!

In the case of the suckler cow Leni, two eggs were fertilised by two sperm from SILIAN. The sperm came once from the Angus bull and once from the Simmental bull. The unidentical twins were born, and you can't tell that they are (half-)siblings. 

 Suckler cow Leni with her twin calves. (Photo : Dario Barelli)