Menu

David Combs: Do cows have to learn how to graze?

[audio:http://news.cals.wisc.edu/wp-content/uploads/2011/04/david_combs_learning_to_graze.mp3|titles=David Combs: How cows learn to graze]

Sevie Kenyon

Some new research about grazing dairy cattle:  We’re visiting today with David Combs, Department of Dairy Science, University of Wisconsin Extension and the College of Agricultural and Life Sciences, Madison Wisconsin and I am Sevie Kenyon.  David, welcome to our microphone.  I’d like you to tell us first, what the situation was that you were looking at with this research.

David Combs

This is a little trial that we’ve been working on for about three years and it’s basically answering a very simple question, I guess: Do cows have to learn how to graze?  Some of our grazers in our state who are trying to serve have had some reservations about whether or not research from our University herd, confinement cows, when they’re put on pasture, is really applicable to their cows who are grazing just about all the time.

Sevie Kenyon

And David, how did you go about answering this very simple question?

David Combs

Basically what we found was, there clearly is a learning curve.  Cows that had never seen a blade of grass, as lactating cows, Heifers that had been raised in confinement and had never seen grass, clearly, for the first couple days they were exposed to pasture, had differences in performance relative to those heifers that had been exposed to grass as growing animals.

Sevie Kenyon

Can you give us an idea of what kinds of things you observed with these cattle seeing grass for the first time?

David Combs

Well we put GPS units on every one of these animals so we could actually track how they walked around the pastures.  And we actually monitored milk production.  What we basically found was within the first couple days of grazing, those cows that had not seen grass before were about 10 pounds less in milk production than those that had experience with grass.  The difference in milk production closed very quickly.  By the end of the first week on pasture, milk production was essentially the same. But in the first couple of days, clearly these cows that had never seen grass weren’t eating as much and didn’t support as much milk.  We also found that, curiously, cows that had been exposed to grass before, actually walked nearly four miles just scoping out that paddock.  While those heifers that had never been exposed to grass virtually stood in the corner of the paddock, looking at the barn and wanting to get back in and walked half the distance. Interestingly, over the course of a week, all the animals, whether they were experienced or not, walked about two miles a day.  So the experienced ones kind of scoped the pasture out the first couple days and then became more efficient.  The heifers that had not seen grass, at some point figured out they were hungry enough that they had to begin to eat and began to actually graze.

Sevie Kenyon

What are some of the management implications from a farmers perspective?

David Combs

From a farmers perspective, probably the kind of common sense things that you already know. If you put an animal in a new environment, probably you provide some feed that they’re familiar with so that they can make that transition.  An abrupt switch causes stress and it takes a couple days for these animals to adapt to that environment.

Sevie Kenyon

We’ve been visiting with David Combs, Department of Dairy Science, University of Wisconsin Extension and the College of Agricultural and Life Sciences, Madison Wisconsin.  I am Sevie Kenyon.