Swiss farmers are for the first time able to choose the sex of their cattle, following the development of technology which enables scientists to identify and separate individual sperm cells prior to artificial insemination.

The first "sexed" calves born in Switzerland were "introduced" to the public on Tuesday, in what scientists are describing as a revolution in the breeding of farm animals.

The technique was developed in the United States by the firm XY Inc., and has been licensed to the Swiss biotechnology company, BIG X.

Using XY Inc's technology, cows from several Swiss farms were impregnated with sperm, which had been selected prior to insemination to produce calves of a predetermined sex. Those cows later gave birth to 12 calves - 11 of which were female - exactly as planned.

Dr Mervyn Jacobson, chief executive of XY Inc, and one of the pioneers of the technique, told swissinfo that having the ability to choose the sex of their cattle was a huge advantage to farmers.

"There are many benefits - in cattle on the dairy side, for example, they particularly want females for milk production.

"There are also other benefits from females, particularly in what is known as 'herd replacement': typically a first calf that is female is easier to produce and less damaging to the mother. On the beef side, farmers want males."

The breakthrough in "sexing" animals has largely been made possible by the development of a machine called a "flow cytometer", which sorts living cells, including sperm, at high speed without damaging them.

Because it is the sperm cells which "decide" the sex of offspring in mammals, scientists were able to identify and separate the individual sperms which code for males from those which would produce females.

Jacobson said the technique has applications in the field of conservation as well as agriculture. "When a species is endangered - down to the last few - you typically need more females, because the female offspring become the mothers and help to rebuild the numbers."

The ability to determine the sex of a living creature before conception raises familiar ethical questions, such as whether humans have the right to alter the balance of nature. In the context of farm animals, Jacobson said this has been happening for years.

"What happens now is that when an animal of the 'wrong' sex is born, it is simply slaughtered. What we are doing is offering a more humane way - if you don't want it, don't have it."

by Jonas Hughes

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