An amount of frozen semen stored for over fifty years in a laboratory was recently used by researchers to impregnate 34 Merino ewes successfully. The birth rate was on par with the one provided by sperm which was frozen for only 12 months.
According to the researchers, the resulting lambs feature a body wrinkle which was often encountered among Merinos during the middle of the 20th century. This particular style was abandoned after it was observed that the skin folds complicated the shearing process and boosted the risk of fly strike.
It is believed that this is the oldest sample of sperm in the world and the oldest sperm which was able to produce successors. One of the researchers noted that the main focus of the study was placed on the reproductive and genetic potential of the semen samples.
Frozen semen sample of 50 years old is still in good condition
In five decades, farmers tried to improve the quality of wool with the help of selective breeding, as they desired to obtain sheep which were superior and more productive. With the help of the lambs, the researchers will be able to compare the older and newer specimens and observe if any significant changes took place.
Before the experiment began, a test took place. The researchers wanted to see if the 50-year-old frozen semen could be used for artificial insemination. The frozen semen, which is stored in vats filled with liquid nitrogen, proved to be in good condition. After some samples were thawed the team verified the motility, speed and overall health of the sperm. The team was fascinated by the fact that they weren’t able to observe any differences between the old sperm samples and sperm which was kept in storage for a year.
Some 56 ewes were inseminated with 34 of them being successfully impregnated. The semen samples were donated in 1968 by the Walker family. The samples were obtained from four rams. The Walker family currently owns 8000 sheep, and they maintain a strong relationship with the University of Sidney.
Rex Austinwas born and raised in Thunder Bay Ontario on the shores of Lake Superior. Apart from running his own podcast (Ice Fishing And Other “Cool” Things), he spends his time canoeing and backpacking in Northern Ontario.. As a journalist Rex has published stories for Global News (Thunder Bay) we well as Buzz Feed and Joystiq. As a contributor to Great Lakes Ledger, Rex most covers science and health stories. Contact Rexhere