熟女无套高潮内谢吼叫免费 ,国产九色91,1级黄色大片儿

This little piggy is a female

(China Daily/Asianewsphoto)
Updated: 2009-06-26 09:37

NANNING: Chinese scientists have claimed a commercial breakthrough after breeding 10 piglets whose sex was successfully selected before conception, heralding potential higher profits for farmers.

A worker hold four female piglets born in one brood at an experimental farm of the Animal Science Institute in Nanning, Guangxi Zhuang autonomous region, June 25, 2009. They were the first pigs in China bred from sperm sorted into male and female chromosomes. [Asianewsphoto]

The healthy piglets were born last week on an experimental farm belonging to the Animal Science Institute in south China's Guangxi Zhuang autonomous region, the institute's top zoologist Lu Kehuan said yesterday.

"They were the first pigs in China bred from sperm sorted into male and female chromosomes," he said.

The piglets were born in two broods, an all-male brood of six last Thursday and an all-female brood of four last Saturday.

Lu and his team separated sperm with the female X chromosome from sperm with the male Y chromosome, and used artificial insemination to inject the separated sperm into four sows.

"Two of them gave birth after 115 days and the other two are due to give birth soon."

Lu said the "custom-tailored" piglets were no different from other newborn pigs in terms of weight and appetite. But the technique is expected to help farmers manipulate birth rates and improve the quality of animal species, he said.

Under normal circumstances, the average gender proportion of male and female piglets is 50:50.

"On many pig farms in south China, a young boar is worth about 5,000 yuan ($715) more than a sow. An all-male brood of six therefore brings in an additional 15,000 yuan compared with an ordinary three male, three female brood," said Lu.

Lu and his colleagues reported their first success in buffalo sex selection in 2006, when two female calves were born with X-bearing sperm.

The technology is widely used today on milch cows in north China's Inner Mongolia autonomous region, whose vast pastures nurture quality cows and milk.

Swine sperm, however, is more fragile and harder to maintain compared to buffalo's, Lu said.

His team had carried out several sex selection tests on pigs before, all of which failed either to impregnate the sows or get the desired gender in piglets.

"Theoretically, the same technique works on all mammals, including human beings," said Zeng Youquan, a member of Lu's project team. "But for legal and ethical reasons, we haven't considered applying it on humans. Nor will we in the near future."

Choosing the sex of children is illegal in China, where people traditionally prefer boys over girls but most couples are allowed to have only one child. Hospitals are also banned from revealing the gender of a fetus to expectant mothers, fearing they might abort a female fetus.

Fetus sex selection, however, is applied occasionally to prevent serious hereditary diseases, such as hemophilia and thalassemia, which are more likely in boys than girls, said Zeng.

Xinhua

Previous page 1 2 3 Next Page

日批在线视频_内射毛片内射国产夫妻_亚洲三级小视频_在线观看亚洲大片短视频_女性向h片资源在线观看_亚洲最大网