Select Sires

Does the Extra Effort of A.I. Pay Off?
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio, Which Aired March 18, 2004
with Nate Zwald,
Ph.D. candidate,
University of Wisconsin

On this week’s Reproductive Moment we will try to determine if herds leaving it up to a bull really out perform herds that use A.I. With us is Nate Zwald, Ph.D. candidate at the University of Wisconsin to answer the question, "Does the extra effort of A.I. pay off?" Nate, does it?

Well, Bill, the quick answer is that it certainly does. As you have mentioned the genetic genes of A.I. have been well documented, so I use the dairy metrics program at DRMS to look at the average performance of some key other management factors for herds, and I broke the herds down into two groups – one using more than 90 percent A.I., and one using more than 90 percent natural service. This gives us two pretty large groups of herds to compare. The A.I. group consisted of over 7,300 herds and the natural service group consisted of over 1,500 herds.

What about reproduction?

Many producers feel that a bull will do a better job of heat detection and insemination than a human. But, in our analysis the average number of days open was just seven net days shorter for the natural service herd than the average A.I. herd. Even though this is an advantage for the natural service herd, it is important to realize that these are averages and with a sound reproduction plan and careful heat synchronization your individual reproductive performance can far exceed that of a natural service herd.

Can you talk about exact breeding dates?

Sure, that is another big advantage of the A.I. herds. Well, one of the things that is often overlooked on the natural service herds is the advantage that having the exact breeding dates is for A.I. herds. We know a cow’s gestation is about 280 days in length. So, if we know the exact date that she was bred, then the length of the dry period can be more consistent. In fact in natural-service herds over 50 percent of the dry periods fall outside the recommended length of 40 to 70 days. This may be even more important, as new research shows that shortening the dry period to 40 days or less may be advantageous, and we know that having cows dry for longer than we expect certainly doesn’t put more milk in the tank.

What is the biggest advantage to using A.I.?

Well, Bill, it is certainly milk production. This is where the genetic differences show up. However, instead of looking at the herds genetic potential, I looked at their actual performance. The A.I. bred herds average about 2,700 pounds more milk per lactation than natural-service herds. Since herds in each group have the same average components percentage, using a take home price of $12.50, (which may be a little modest) we can show about $337 growth income per cow, per lactation, for A.I. bred herds. This shows that certainly more money spent on A.I. semen will put more money in your pocket.

Thank you Nate. This week’s Reproductive Moment has been with Nate Zwald, Ph.D. candidate at the University of Wisconsin.

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