How many cattle can graze?

Transcript for August 19, 2017

How many cattle can graze?

Lyndall Strout >>> Hello, everyone, and welcome to SUNUP. I'm Lyndall Stout. Our conversation begins today in the pasture,and a two-part demonstration using OSU's mobile grazing app. It can help prevent overgrazing. Alex Rocateli gets us started with the first step, which is taking measurements.

Alex Rocateli >>> For we estimate forage availability for cattle, or for a hen, in a pasture like that, using the GrazeOK app. Why do you need to collect is pretty much, plant height and plant cover. For instance, I have the grazing stick here, so that's pretty much what you need to do, is come and take the forage height, and after we need to take the forage cover, and when we press our hand, you can see that we are going to find the average height of leaves, that's pretty much where most of the forage is. Mistakenly, you could say that has one meter, three feet of forage, you go down about 15 inches. I talked to Dave Lalman, and he mentioned to me that this field is not being fertilized, and is being managed pretty much as a native pasture. So I would say, in this case, let's treat this as a native pasture, and as a rule of thumb in native pastures, we say let's graze half and leave half. If you wanna graze or hay, the best time is right before Independence Day. That's pretty much early July. Now we are going late July, so our crude protein ran a drop from 13, that's excellent, to very good quality, to about a 10, I would say the 10. Well, that's still good quality for steers and heifers, and we know that Johnson grass is the ice cream plant. They already like it, Johnson grass. My assumption is, as soon as we introduce cattle here, they will go straight and select  the Johnson grasses. So, pretty much what I did here, I walked in zig zag and I didn't select any location, I tried to take it at randomly, and I just measured the plant height and I also came up cover. And after that, that we collect all this information, we need to go to the GrazeOK app, and input out those values. You see that we have total grazing days equals to 12, so we say, looks like, that according to our  calculations, this pasture can hold 131 animal units for 12 days. So I'm gonna, right now, email this information to Dr. Lalman, and he is gonna introduce the cattle here, and let's see how accurate that app is.

David Lalman >>> Dr. Rocateli sent an email and he had calculated the stocking area based on his estimated forage availability, so bottom line is, we've got 152 weaned calves here. Their animal unit equivalent, if you remember, animal unit equivalent is a 1,000 pound cow per day with her calf year round, with an average forage consumption is 26 pounds per day. So these calves, you'd estimate .875, so that gets you to about 23 pounds of estimated forage consumption per day. We think, if we strive to harvest about 50% of what's out there available, 25% of that getting tromped on, laid on, eaten by bugs, by deer, so on and so forth, and the other 25% actually consumed by the cattle, Dr. Rocateli's estimates are that in about 12 days, this forage in this pasture will be utilized at somewhere in the neighborhood of 50% harvest efficiency. As you'll see, we're late getting to this pasture this year. We'd expect the protein concentration in this pasture to be below these calves growth requirements at about two pounds per day, average daily gain. We can support two pounds a day with the equivalent of about one pound per day of a high protein, meaning 38 to 40% crude protein supplement. And that's what those guys will put out here with the feed truck in just a few minutes. If he overestimated for supply, in 12 days we'll be beyond 50% harvest deficiency then, and we'll blame him for overgrazing our pasture. (laughing) On the other hand, if he underestimated it, we'll have 55 or 60% of the forage left out there in the pasture. And so, you know, you'd consider that a slight under utilization, which is probably a better scenario to be in.

When to pull cattle off the pasture?

Lyndall Strout >>> Here we are in the pasture 13 days later with Alex Rocateli. And Alex, you're following up and getting some measurements today?

Alex Rocateli >>> Right, yes.

What I gonna be doing here is assessing how good the GrazeOK app did on estimating forage. Availability in this pasture, so, what I need to do now is remeasure it, and cross my fingers to see if the app did a good job. So let's get started.

Lyndall Strout >>> Okay.

Alex Rocateli >>> All right. So, first, before I measure, we place the cattle here pretty much in a continuous grazing, as Lalman told me, David had told me. And as you can see it's pretty common that that happens they have a lot of waste here, see. Right here you can see that the cattle pretty much didn't graze it they just trampled around it didn't utilize it. If you go in a rotation system what's gonna happen is they will end up grazing all that biomass, all that forage. So that's something we need to account when we have continuous graze situation is that we are gonna have some waste and when you're remeasuring to see how good was the forage remove it we need to avoid those areas because that was already accounted to not be used. So here you can see that's an area pretty much where the cattle came and grazed. So you can see also they trampled a little bit and it's kind of laying down. So what I need to do first is put those plants back to their original stand and then we try to measure. And again as I mentioned before we are not gonna measure the highest leaf, we are gonna press and when we reach we will feel that most of the leaves are reaching or at my hand is where I'm gonna measure. As you can see here if we do it I can feel this about here I would say that we are almost seven inches, seven to seven and a half inches of biomass now. So what happened is 13 days ago we came here and I measured 13 inches of biomass. And now we're measuring seven and a half. According to my measurements I was expecting that that biomass go down to six inches the month before that to have. In this case looks like the Graze OK app underestimated the amount of biomass that they have here.

David Lalman >>> We started about well I guess it was 13 days ago, turned this group of calves as I recall about 152. Calves that we turned out on that pasture that Doctor Rotelli spoke about. And so the guys have just pulled these cattle up into the pens are actually  gonna be shipped on a truck tomorrow morning to go to the feed yard. And they should be weighing, they're gonna be weighing real close to eight by now.   (cows moo)  They were weighing 765 or so about two weeks ago. And the overall goal is low cost of production and long term sustainability of your natural resource. In this case primarily that being the pasture. And so  with a relatively small pasture, a pretty nice size group of calves we just calculated or estimated how much standing forage was available and we're just trying to see how close we could get using the extension tools that are available for grazing management.

Lyndall Strout >>> Lots of good insight though and then I guess it's important to take records from year to year and season to season.

Alex Rocateli >>> Exactly right. That's the main point here. Season after season just make a record and learn with the different  environments that they're gonna have. And I believe that after five, six years that you are doing your records and paying attention to your pasture you're gonna excel and know exactly how the pasture works.

Lyndall Strout >>> Terrific, great demonstration by you and Dave Lalman. Alex thanks a lot.

Alex Rocateli >>> Thank you.