Select Sires

Which Surface Is Better for Heat-Detection, Concrete or Dirt?
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio, Which Aired March 25, 2004
with Milan Shipka,
Department of Animal Science,
University of Alaska

Today’s Reproductive Moment is with Milan Shipka, who comes to us today from the Department of Animal Science at the University of Alaska. Recently Milan did a field study on which surface was better for heat detection, concrete or dirt.

Yes, Bill, what we did is we had 24 high-producing, two-year-old, first-calf heifers. They were from a high-producing herd, and just to verify that we followed them through their complete record. On average they produced over 25,000 pounds of milk in 305 days. They were just over 60 days open in milk when we started the project and they were housed in an open, free stall barn with a concrete floor. What we did is we moved the cows onto a dirt lot beside the free-stall barn for six hours each day, three hours early in the morning and three hours in the afternoon. We used an electronic radio telemetric heat-watch system to detect heat and the farm crew was also responsible for observing heats. For this project, we relied 100 percent on the radio telemetry to verify heats.

What were the results?

The most significant results that we found was that for 36 percent of the heat periods we observed, mounting activity occurred only on the dirt lot. To put that in a better perspective, if we were to have 100 cows, it would have been 36 cows. If we had 1,000 cows there would have been nearly 360 cows that only showed standing heat on the dirt lot. Other significant results of the 147 mounts recorded, 82 of those mounts, or 56 percent, occurred during the six hours the cows were on the dirt lot, leaving the other 65 mounts recorded during the other 18 hours of the day. Of the 82 mounts recorded on the dirt lot, 47 came during the first 30 minutes of each three-hour period.

The last significant result is that of the 31 individual heat-periods that we observed during the study, 14 of them had their first mount during the first 30 minutes of each three-hour period on the dirt lot.

What can large dairies do to take advantage of what your study showed?

I know it is difficult for large dairies to get their cows off concrete, but according to this study you have a greater chance to detect the cow in estrus on a dirt surface compared to concrete. We know that estrus behavior, meaning one cow standing to be mounted by another cow, is driven by the hormone estrogen at the time around ovulation. Many of us have a tendency to think that just because the hormone is there, she will show heat. Well, this study shows that environmental factors can play a big roll in determining when she shows heat. This is something I know that many dairy herdsmen have probably known for a long time. Let’s go back to the number of estruses that had their first mount during the first 30 minutes of each three-hour period, 14 out of the 31 total estrus periods. So a suggestion may be to allow open cows and those not yet confirmed pregnant onto a dirt lot for at least two one-hour periods a day if possible. At the very least, just consider your herd’s reproductive potential when facing a building or remodeling project. It could lead to more pregnant cows and improved reproductive management in your dairy herd.

So, that is quite a study you performed, who helped you out with that?

I really want to give kudos to a young man named Hernando Lopez. When we did this study he was working on his master’s degree with me, and he is now pursuing and doing a great job with his Ph.D. degree at the University of Wisconsin, Madison.

Milan Shipka, associate professor of animal science at the University of Alaska.

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