Select Sires

Sex Selected Semen (Part One)
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio Which Aired Dec. 15, 2005
With Ray Nebel,
Extension Specialist and Professor of Reproductive Management,
Virginia Tech

Ray, this week we are talking about a new technology in gender-selected semen.

Yes Bill, it is really kind of interesting that the technology has probably been researched for hundreds of years, as far as how do we select for male and female offspring, but it has just been in the last few years that a patent was obtained by no one else but USDA, US Department of Agriculture. The marketing rights were bought by a company in Colorado known as XY. Then, just recently, there is a company in Texas, Sexing Technologies, that is now actually sorting this semen from bulls.

So, tell us more about the process of this technology.

Right now it is the only technique that is very repeatable and accurate. It is flow-sorting technology. They use what they call a mo-flow cell sorter. One machine costs $300,000, and this company has bought ten, so that they run continuously, 24 hours a day, in three eight-hour shifts. These machines are very expensive, and they are very sophisticated. The cells are first stained for the DNA content, and the X chromosome has more DNA than the Y chromosome. Then it goes through this machine. The cells go through single file, at 60 miles per hour, and they are under pressure at 40 to 60 pounds per square inch (psi). When the laser beam hits each sperm individually it fluoresces, and so the Y sperm are not quite as bright as X sperm. They are sorted based on electromagnetic fields to the X population, which would be heifers, and the Y population, which would be bulls.

There is a pretty high percentage of purity, isn’t there?

Yes, there is. Not every cell can be sexed because of configuration of the sperm cell. It has a very flat head and a long tail. The laser beam has to hit the head straight on like a frying pan. If the cell is not in the orientation, or not in the position to be in that location, it is not sorted. But cells that are sorted are roughly 90 percent accurate. It is really pretty accurate for the sorting of the X and Y chromosome.

What are some of the limitations of this?

There are a few limitations. One I told you about are the machines themselves, being $300,000 apiece. It is not like you or I could go buy one of these to put in our garage. Then, the person who performs this technology, the technician that runs the machine, has to be highly skilled. The sperm have to be handled as optimally as possible to be stained and to go through the machines. The other big limitation is the speed. Because they go through one cell at a time, they can only get about seven and a half straws per hour. These straws contain 2,000,000 sperm instead of the traditional 15 to 20 million. There are a lot fewer sperm per straw, but with the sexing taking as long as it does, only seven and a half straws per hour. There is a big limitation there.

We will continue with our discussion of Sex Selected Semen with Ray Nebel, Extension Specialist and Professor of Reproductive Management at Virginia Tech.

Select Sires Inc., 11740 U.S. 42 North, Plain City, Ohio 43064 / Phone: (614) 873-4683 Fax: (614) 873-5751