Select Sires

Research Suggests
Batch-Thawing Semen Does Not
Compromise Fertility
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio, Which Aired Sept. 26, 2002
with Dr. Joe Dalton, extension dairy specialist,
University of Idaho

Today’s Reproductive Moment is with Dr. Joe Dalton, extension dairy specialist for the University of Idaho. Dr. Dalton has just completed a large study on the effect of batch-thawing semen straws on conception rates in dairy cattle, and he's here to share that with us today. Dr. Dalton.

Thanks very much Bill. Eight dairies, located in Idaho, Washington, California and Ohio, were used in our study. Four of the dairies used professional A.I. technician service, and four used herdsman inseminators.

And, how did you set up the research?

Initial recorded data included beginning thaw time, cow identification number and time of artificial insemination. A minimum of four straws, thawed simultaneously, was required for data to be included in our study. After pregnancy diagnosis by the herd veterinarian, records were retrieved and then analyzed. There were over 1,000 inseminations in the data-set. The average elapse time from the initial thaw to completion of fourth A.I. was different for professional A.I. technicians and herdsman inseminators.

Really, how different?

Professional A.I. technicians completed the fourth insemination in approximately eight minutes, while herdsman inseminators required nearly eleven minutes.

So why the difference there?

This time difference may be due to many factors, including walking distance from the A.I. preparation area to the cows.

And what were some of your findings?

There was no effect of sequential insemination numbers for either professional A.I. technicians or herdsman inseminators. However, the average conception rate achieved differed between professional A.I. technicians and herdsman inseminators. Across four straws, professional A.I. technicians achieved a conception rate of 45 percent compared to 27 percent for herdsman inseminators. Although the average conception rate differed between professional A.I. technicians and herdsman inseminators, a lapse of time and sequential insemination numbers had no effect on conception rates within the inseminator groups. Therefore, in contrast to earlier studies utilizing limited numbers of cattle, our conclusion is that careful professional A.I. technician and herdsman inseminators may thaw four straws simultaneously without compromising conception rates.

We are currently investigating the factors that may contribute to the difference in the average conception rate achieved between professional A.I. technicians and herdsman inseminators.

What can producers take away from this research?

A rule of thumb is to never thaw more straws than you are able to deposit in cattle within 10 to 15 minutes. All A.I. technicians must remember that a successful A.I. program must not only be labor efficient, but must also incorporate proper semen handling techniques.

Thanks, Joe. That’s Dr. Joe Dalton, an extension dairy specialist for the University of Idaho. This Reproductive Moment™ has been brought to you by Select Sires.

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