Chitwan, February 28 National Cattle Research Programme Rampur Chitwan has introduced a new technology that helps to breed only females from mother cows. The technology uses sperm prepared from sexed semen imported from the USA. According to National Cattle Research Programme Rampur Coordinator Dr Madhav Acharya, x and y chromosomes are separated from the bull’s sperm. The sperm containing ‘y’ chromosomes are imported from the US and then, the mother cattle are made to conceive artificially to breed female calves. “We have used this technology becuase the male calves are unproductive and it is tough to manage them,” Acharya said. This technology is being used at Rampur, National Cattle Breeding Centre Pokhara and some other big commercial firms. After using the technology on 50 cattle, seven mother cows gave birth to female calves only. According to him, conception by the cattle through artificial insemination is just 25 per cent. Acharya says that Nepal is working to produce sperm in Pokhara. As the machines needed for separating chromosome are very costly, preparation is under way to install such machines in Pokhara for sperm production. The use of the bull’s sperm imported from USA makes the cattle give more milk and calves gain good weight after they are born.