World''s oldest semen successfully used to impregnate sheep : The Tribune India

Join Whatsapp Channel

World''s oldest semen successfully used to impregnate sheep

MELBOURNE: World''s oldest viable semen - isolated from rams and stored for over 50 years in a laboratory - has been used to successfully impregnate ewes, scientists say.

World''s oldest semen successfully used to impregnate sheep


Melbourne

World's oldest viable semen -- isolated from rams and stored for over 50 years in a laboratory -- has been used to successfully impregnate ewes, scientists say.

The resulting live birth rate was as high as that from sperm frozen for just 12 months, researchers said.

"This demonstrates the clear viability of long-term frozen storage of semen. The results show that fertility is maintained despite 50 years of frozen storage in liquid nitrogen," said Simon de Graaf from the University of Sydney.

"The lambs appear to display the body wrinkle that was common in Merinos in the middle of last century, a feature originally selected to maximise skin surface area and wool yields," he said.

"That style of Merino has since largely fallen from favour as the folds led to difficulties in shearing and increased risk of fly strike," he said.

"We believe this is the oldest viable stored semen of any species in the world and definitely the oldest sperm used to produce offspring," said Jessica Rickard, a post-doctoral fellow at University of Sydney.

De Graaf said that it was the reproductive biology and genetic aspects of these as-yet unpublished findings that were of most interest to him.

"We can now look at the genetic progress made by the wool industry over past 50 years of selective breeding. In that time, we've been trying to make better, more productive sheep," he said.

Rickard did the original work to determine if the stored semen was viable for artificial insemination.

This involved thawing the semen, which is stored as small pellets in large vats of liquid nitrogen at minus 196 degrees.

The team then undertook in vitro tests on the sperm quality to determine the motility, velocity, viability and DNA integrity of the 50-year-old sperm.

"What is amazing about this result is we found no difference between sperm frozen for 50 years and sperm frozen for a year," Rickard said.

Out of 56 ewes inseminated, 34 were successfully impregnated. This compares to recently frozen semen from 19 sires used to inseminate 1,048 ewes, of which 618 were successfully impregnated.

This gives a pregnancy rate of 61 per cent for the 50-year-old semen against 59 per cent for recently frozen sperm, a statistically equivalent rate. PTI

 

Top News

Jailed gangster-politician Mukhtar Ansari dies of cardiac arrest

Jailed gangster-politician Mukhtar Ansari dies of cardiac arrest

Ansari was hospitalised after he complained of abdominal pai...

Delhi High Court dismisses PIL to remove Arvind Kejriwal from CM post after arrest

Delhi High Court dismisses PIL to remove Arvind Kejriwal from CM post after arrest

The bench refuses to comment on merits of the issue, saying ...

Arvind Kejriwal to be produced before Delhi court today as 6-day ED custody ends

Excise policy case: Delhi court extends ED custody of Chief Minister Arvind Kejriwal till April 1

In his submissions, Kejriwal said, ‘I am named by 4 witnesse...

‘Unwarranted, unacceptable’: India on US remarks on Delhi CM Arvind Kejriwal’s arrest

‘Unwarranted, unacceptable’: India on US remarks on Delhi CM Arvind Kejriwal’s arrest

MEA spokesperson says India is proud of its independent and ...

Gujarat court sentences former IPS officer Sanjiv Bhatt to 20 years in jail in 1996 drug case

Gujarat court sentences former IPS officer Sanjiv Bhatt to 20 years in jail in 1996 drug case

Bhatt, who was sacked from the force in 2015, is already beh...


Cities

View All