Select Sires

Sex Selected Semen (Part Three)
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio Which Aired June 9, 2005
With Ray Nebel,
Extension Specialist and Professor of Reproductive Management,
Virginia Tech

Ray, we continue our discussion about sex-selected semen. What is the availability today?

Select Sires had just added two new Holstein sires to the lineup, and two new Jersey sires. Because of the cost of the sorting, the cost of sex-selected semen is out of the control of Select Sires at this time. It is a third party that does the sorting, and they have just added two bulls to the Holstein lineup, so there are five bulls available that vary in their genetic potential, and three Jersey sires. Eight sires are available today that are being put out for general use to really better manage heifer herds by taking advantage of this technology.

Is there a recommendation on how many units to start with?

At the beginning of the year Select Sires put out 5,000 units of the sexed semen from three Holstein bulls and one Jersey bull. This 5,000 units total was to get a handle on some of the experiments that have been done recently to increase the conception rate. That data is coming back now, and it feels fairly confident that there have been improvements, and that the conception rates will be acceptable for most individuals. It is not a bad recommendation to get between 30 and 40 units of semen. Ten units are not enough to really get any practice or any handle on what is going to happen. My recommendation would be 30 to 40 units of semen to use on virgin heifers and to then see how it works on your farm. Run a little, so that you can feel confident with it before you make a large investment.

We had one farm, locally, buy only 150 units, and it has worked out really well. I would say for most farms to start in slowly, get some experience, and then make their judgment from there.

How do they come up with the probabilities?

With the probability of course, we are saying it should be 90 percent heifers, 10 percent males, because we cannot sex out totally all heifer and bull semen. There are odds. It is going to be 26 percent of the farms where it is going to be fewer of the herds that have 80 percent or less offspring that will be heifers. It is determined by probability. In fact, there are one percent of the farms that are going to end up 50/50, so 99 percent of the farms should skew to some percent. About 30 percent of the farms will have 100 percent heifers. On average, if we take all the farms out there breeding with sex-selected semen, we are going to have, on average, 90 percent heifers. But you need to realize the probability is that with 20 offspring you could get 80 percent heifers or 70 percent heifers or, in the rare case, be in that one percent that gets 50/50. [With probabilities, the higher the number of samples, the closer the results are to the average.]

This technology, of course, is new, so it continues to evolve or develop along the way?

Definitely, Bill. There is research going on now that will help in the freezing of the semen cells. Although bulls are collected normally, they are stained and run through the machine. After they are collected, they are frozen. There is technology being developed right now that might help on the freezing of these cells and will also be used across-the-board on conventional semen. This technology has really pushed a button on whether can we do a better job in freezing. Maybe we have gotten a little bit lax in saying we are doing a good job, and now we are looking for improvements wherever we can.

We are looking for results of the research phase perhaps later this year?

Probably it will be December [2005] before we can get some results back. Some lab work is going to be done and probably some initial testing out in the field, but I would suspect into fall or early next year we will have additional advancements in the technology.

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