The Moos Room™

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Dr. Joe Armstrong: Welcome to the Moos Room, everyone, hosted by the University of Minnesota Extension. I'm one of your hosts, Dr. Joe Armstrong. Co-hosts are usually Emily Krekelberg and Brad Heins. This is a bonus episode. One of the big things you'll notice right away is Emily is not on the episode. She had some things come up and we just have to keep putting stuff out. I've called in a ringer. Kirsten Sharpe is with us. Dr. Bradley J Hines is a grad student up at Morris. We're going to talk mostly about solar panels in this episode. Solar panels and grazing and how the two work together.
You'll notice at the end we have a pretty sharp cutoff as we go to a break to the next episode. What happened is Kirsten has a lot of research that she's done with Brad and Morris at the West Central Research and Outreach Center. We just had too much good information. We had to break it into two episodes. It just got a little long, but I couldn't cut any of it out. It was all good information. Really happy that she was willing to come in last minute and talk to us.
The other thing you'll notice, maybe you'll enjoy it, I tried to edit it as much as I could to get out of it, but I can't, stuck my foot in my mouth right away, it is Kirsten Sharpe, not Kirsten Sharpe. You'll hear me say her name wrong at least twice before she corrects me. Again, just apologies for that. No way around to edit out of it. I have to own it. Enjoy that moment as I stick my foot in my mouth. Hope you enjoy the episode. Thanks for listening. Enjoy our talk on solar panels and grazing. Welcome, everybody. Today you're back in the Moos Room. Like I said in the intro, Emily is not with us today. Who is here is Bradley J Heins. Dr. Bradley J Heins is a grad student.
Bradley: Don't forget that.
Joe: Sorry. I almost forgot. Tenured professor with the UMN, and Kirsten's here. This grad student is going to talk to us a little bit about a couple of projects she has going on that she's leading. First of all, I guess we should hear from Kirsten and see who she is. She can let everybody know where she came from, why she's wearing the hat she's wearing, those kind of things.
Kirsten: [laughs] Just to clarify, it's pronounced Kirsten.
Joe: Sorry.
Kirsten: That's okay. Everybody gets it wrong. It's either Kirsten or Kristen.
Bradley: I called her Kristen once.
Kirsten: [laughs]
Joe: Kirsten.
Kirsten: Yes, or Krista. I've gotten that sometimes. It's totally okay. I grew up in Bemidji, Minnesota. It's in the Northern part of Minnesota. I did not grow up with a background in Ag at all and I really got my first taste for agriculture of any sorts when I was a junior at the University of Minnesota, Morris. I started working part-time moving cows at the West Central Research and Outreach Center. Basically, was moving cows from the pasture up to the milking parlor to be milked and back out to the pasture. I just fell in love with dairy and agriculture and it just clicked for me. After the part-time job at the Rock, I started an internship with Brad, spent the summer with Brad as an intern. After that, I got hired at-
Bradley: Remember you just clipped pasture samples all summer. That's all you did.
Kirsten: Basically.
Bradley: Nothing but grass all summer
Kirsten: Clipped pastures, scooped poop.
Joe: Oh, that's how you're supposed to start, right?
Kirsten: [laughs] Yes.
Brad: That's right.
Kirsten: That's what interns are for. [chuckles] It was an awesome experience. I met two of my good friends that were also interns that summer that way. We've stayed in touch and we've continued to be good friends from that experience. After that internship, I got hired at the West Central Research and Outreach Center as a full-time researcher in renewable energy. I worked on doing basically energy audits on commercial swine barns near Morris.
We collected energy use data. We looked at electricity and propane and natural gas use from six swine farms and worked on that project for about three years, I think. Brad finally was able to get me to be his grad student starting in January 2017. I knew that I wanted to go back to dairy and I did know that I wanted to get my master's degree as well and I wanted to work with Brad. I became his grad student in 2017 and I just sent him the fourth copy of my thesis now yesterday. Hopefully, he doesn't have too many edits infractions and I can just hand it in because it's due March 31st. We shall see.
Joe: The pressure's on Brad now, which is good.
Bradley: That's right, but you did successfully defend your thesis-
Kirsten: I did.
Bradley: -three weeks ago.
Joe: Congrats.
Bradley: You are one step closer to an MS.
Joe: One step.
[laughter]
Bradley: One final step away that I have to approve.
[crosstalk] [00:05:44]
Joe: You got to be nice to Brad for just a few more weeks.
Kirsten: Yes.
Bradley: That's right.
Joe: One of the projects that Kirsten is working on is solar panels and grazing. Why don't you just give us a quick overview of where did it start? Where did the idea come from? Maybe Brad had already started some stuff, but where did that all come from?
Kirsten: Sure. At the West Central Research and Outreach Center, we have a lot of renewable energy systems. We have several solar photovoltaic systems, we have some small-scale and large-scale wind turbines, we have some solar thermal panels. We have a wide variety of renewable energy technologies. I think Brad definitely started this project. Really, we just wanted to think of a new way that farmers could use renewable energy as well as a benefit to their livestock.
Basically, today, farmers are really facing a lot of challenges, and we wanted to have a novel idea for farmers to use, in which they could produce their own energy, not really rely so much on fossil fuel energy. We erected a 30-kilowatt solar photovoltaic system in one of our pastures with the goal of producing electricity while also shading our cows, some of our milking cows.
Joe: Give us an idea of how big that is, because to me when I hear that number, I really don't know what that means.
Kirsten: It ranges from seven to nine feet from the ground and it's mounted on some big-- Are they cement or steel poles, Brad?
Bradley: They're steel poles cemented in the ground.
Kirsten: A 30-kilowatt system. I am not good at estimating how big it is, but it's a pretty big system. We could fit probably, oh gosh, maybe--
Bradley: 40, 50 cows underneath it.
Kirsten: 50 cows underneath.
Joe: That's enough shade for 40 or 50 cows.
Kirsten: How long would you say it is, Brad?
Bradley: I think it's about 50, 60 feet long.
Kirsten: There's two banks.
Bradley: There's two banks of them each at about 40-- I think they're at 35-degree angles facing south to get maximum sunlight, I guess.
Joe: With the study, what was the goal? I know you said you're trying to help farmers, give them some different options, but what did you come up with as the goal of the study? What were you trying to find out?
Kirsten: Our goal really was to, like I mentioned before, produce electricity while also shading cows. This new concept I actually heard about probably a month ago called agrivoltaics, which I didn't even know that this was a thing that people were doing, but it's integrating agriculture with solar PV. We've done a little more research on agriv,oltaics and basically, the goal is to incorporate the two together to increase land efficiency.
Some studies have shown that incorporating PV systems and Ag together could increase land efficiency by 75%. With our system, we wanted to provide shade in the form of solar shade. It's an interesting concept to think about. You're collecting energy from the Sun, but you're also providing a cooling effect to cows. We actually gave the cows smaXtec Boluses, which just go in the reticulum. The boluses record, internal body temperature, and they also record a proprietary activity measurement. We could tell what the body temperature of our cows were and also their activity from those boluses. Our overall goal was to show that cows that had shade had a lower internal body temperature compared to cows that did not have access to shade of any type.
Joe: Perfect. You're measuring that in production, right? It's milk output components as well, but also just the straight activity?
Kirsten: Yes. We measured a wide variety of variables. We looked at milk production, we looked at fat and protein, we looked at respiration rates, internal body temperature, like I mentioned before. We also recorded behavior. We wanted to see if cows that were in the shade had less fly pressure, so we looked at fly pressure.
Joe: Did you think they would have more or less fly pressure in the shade?
Kirsten: Honestly, I wasn't really sure about what was going to happen with the flies. I didn't really have any clue. Brad, what did you think?
Brad: I didn't really expect there to be much difference in flies. These are all cows on pasture, so I wasn't sure. Who knows, maybe they had less-- the thought was maybe they would have less flies underneath the solar panels, but we just didn't really know. We thought we'd collect it anyways and just see what would happen.
Joe: How did you measure that?
Kirsten: Oh gosh. Yes. It was myself and three interns, and we went out to the pasture twice a day, once in the morning, once at night, and we watched every single cow for, I think it was basically a total of five minutes per cow. We spent quite a few hours out in the pasture recording head tosses, skin twitches, tail switches, leg stomps, which would be indicative of fly avoidance behaviors. We also counted-
Joe: That's a lot of time.
Kirsten: Yes. We also counted flies on cows, so we counted stable flies, face flies, and horn flies.
Joe: I want to see you do this with a set of beef cows, angry beef cows.
Kirsten: Oh, yes, [unintelligible 00:12:39]
Brad: I don't think you could do that.
[laughter]
Kirsten: Yes, we took a lot of measurements on these cows to just really learn about what was going on and be able to compare those cows in the shade versus cows with no shade.
Joe: What did you find? Did you find that the cows in the shade-- I would assume they were cooler, right?
Kirsten: We'll start with, fly avoidance behaviors weren't different at all between the cows, like Brad thought. The cows were in the same pasture, but just in different paddocks. They were relatively all close together, the cows that had shade and the cows that didn't have shade, so flies, really, were just able to transfer across the whole pasture. We didn't see any differences in flies or fly counts or fly behaviors.
Respiration rates. In the morning there were no differences between the cows that had shade versus the no shade cows, but in the afternoon, the shade cows had significantly lower respiration rates. They had about 66.5 breaths per minute compared to the no shade cows, which had almost 80 breaths per minute.
Joe: That makes sense. Yes.
Kirsten: Yes. That right there really shows you that the shade definitely helped to reduce some of that heat stress that cows were seeing on pasture.
Brad: When you think about heat stress, most people are thinking about does it have an effect on production, and what did we find there? It was maybe a little surprising to us.
Kirsten: We didn't see any differences in production, milk production, no differences in fat and protein. We did this study for four periods last summer. The periods maybe ranged from five days to a max of seven days on the study. I personally think that we didn't have the cows on the study for long enough to be able to see a real difference in milk production. I think that if we would've had the cows on the study for the whole summer, we would've seen a difference.
I maybe even think that no-shade cows would have slightly higher milk production than the shade cows because the shade cows hung out under the solar panels. They sought the shade over grazing from times. I think that maybe no shade cows grazed a little bit more because they didn't have any shade to stand in, but that's just my thoughts.
Joe: That�s interesting. Yes. You were out in the pasture a lot, so you got to see it.
Kirsten: Yes, we were. That's just my thought. Brad doesn't think that there would be any difference, even if it was the whole summer.
Brad: I don't know. [crosstalk] It's hard to tell. They're under the shade, but they're still being affected by the other environmental effects on them. I'd like to think that they would have higher production, but I'm just, I'm not sure.
Joe: I would love to think also that they would've higher production, but usually, with stuff like this, when there's that many other variables besides just the shade, what you see is you see other effects of the stress rather than production, because we've bred cows to think about production first, actually, at their own harm sometimes. I think they maintain that production. Did you guys look at disease incidents or mastitis rates or anything compared between the two groups?
Kirsten: We didn't, no. We didn't compare those. Especially in a pasture-based system, if you have a solar system that is immobile and it's just stationary in your pasture, well, you can't have your cows use that shade structure the whole summer because they need to rotate through the pastures.
Joe: Right. That's a good point.
Kirsten: If there was a mobile system that we could have used and could rotate it among the pastures with the cows as they grazed, I really do think you would see a difference in production
Joe: If it could move with them?
Kirsten: Yes. The body temperature results were pretty significant. The shade cows had significantly lower body temperatures during the daylight hours. Basically, starting at 11:00 AM to noon, actually, up until midnight, the shade cows had about almost a whole degree Fahrenheit lower body temperature than the no-shade cows.
Joe: Yes. That's pretty typical when we talk about heat stress, and I think people forget about it. I guess this is going to probably lead to an episode on heat stress. Yes, when we see really hot temps, the biggest factor on whether or not it's going to affect cows or anything on the beef side too is does it cool off at night? If it doesn't cool off at night, they don't get a chance to cool down and then it snowballs on you and gets out of control, but they hold that heat for a long time. You don't want to--
On the beef side, we really worry about guys that decide, "It's hot, so I'm going to try to work my cows after dark at night," and that's actually probably the worst time to do it. You want to get up as soon as you can in the morning so they're cold to start or they've had all night to cool off. Yes, that's not too surprising that they held their heat that long. With the production not being different, did you guys go into any economic analysis or did you even bother?
Kirsten: I did not for my part of the study, I think we probably will look into that. Maybe Brad has a little more insight on the economics.
Brad: Yes. I think at some point we may do some economics. I'd like to do this over a longer period of time, maybe the whole summer over a couple years to see really what happens. This was the first real study of it. This really hasn't been done anywhere else in the world. This is the first time we're at the forefront here, so we're just learning as we go. It probably asked more questions from this study than what we got answers, which is a good thing. Yes, that'll be one of the things that we'll look at into the future if we get successful to be able to do more projects.
Joe: Perfect. Yes, I'd be really interested in to see the difference in prevalence of certain diseases, whether that's mastitis or RPs, especially fresh cows. If you had fresh cows out there, I think there'd be a very big difference as they're ramping up to try to get to peak milk. Again, like you said, you'd have to be able to move that stuff around with them.
Kirsten: Yes. I think that it may be a little more challenging for maybe a pasture-based milking cow system, but what about dry cows that are housed in a lot or heifers? I know a lot of times farmers do provide heat abatement to those animals, even if you have beef cows who have a black coat that basically they have more-- What's the word? They gain more solar radiation because of that black coat color. Well, if you have just a standard shade system, that's great. That's awesome for your animals. You could have a solar system that not only shades your cows, but also is providing you revenue yourself as a farmer. I think that even in different settings, that could be a pretty useful thing.
Joe: I totally agree. I think it would be great for our beef farmers to get involved in this, because they are thinking about shade a lot, especially anybody who's got Angus. If you can get something back out of your shade structure, why not?
Bradley: I think if you think about it from an economic standpoint of getting some energy back, this is a 30-kilowatt system. A typical family house uses maybe five to seven kilowatts is all the solar you would need. This 30-kilowatt system, you're really running maybe six to eight houses, really, is the energy that it's producing for. It does produce a lot of energy. There is a lot of payback to the farmer in many different ways.
Joe: I really like it. We're close to another Joe's soapbox issue, I guess.
Bradley: [laughs] That's all right. Go ahead.
Joe: I really hate seeing these solar farms go up and stuff that is agricultural land. This is a way to still use it for both. I hate when I see pasture get taken away or cornfields get taken away to put these giant solar gardens up. There's got to be a better way looking not at the short term, at the long term and doing stuff like this instead. To use the land efficiently, all the land stewardship issues, I really don't get taking agricultural land away and not being able to figure out a way to use both.
Kirsten: For sure. There are studies that have been done in other countries where-- If you just Google agrivoltaics and you look at the images on Google, it's amazing. Very cool. There are studies that have been done that show that growing crops, maybe not corn, but alfalfa, those crops grown under PV systems, they require less water and they also cool the underside of the PV panel. That increases the panel efficiency and you're producing more electricity, which is pretty cool. These systems are not the typical systems that you would see along the highway, they're pretty high off the ground. A couple of pictures have combines combining soybeans underneath the solar panels.
Other countries I think are actually incorporating cropping systems into photovoltaic systems, which I think is very cool. Very neat. Just something that I think could be very beneficial to farmers, especially even in Minnesota. If you have a field that sits during the winter and you're not necessarily growing anything on it or getting revenue at that time, well, you could be producing electricity on that land, which would increase your land efficiency, maybe even up to 50%, 75%.
Joe: Absolutely. I just Googled it, like you told me to. It is really cool. How they're integrating it. What's really cool is that it feels like it's synergistic. You'd think there'd be some trade-offs a little bit, but the fact that you got less water use, all those things that you're saying, that's really, really cool. Well, let's get off of solar energy and go on to just energy use on a dairy because I think it ties in really well, and this is the other project you've been doing, right?
Kirsten: Yes.
Joe: Thank you for listening to part one of this two-part bonus episode. Like I said in the intro, we had to cut it a little short just because we had too much good information. Come back next episode, we'll have Kirsten back with us and we'll talk about the second part of her research that is talking about general energy use on dairy farms. Make sure you tune in, come back, but that's a wrap on this first part of this episode.
As always, if you'd like to learn more, need something to reference, please visit extension.umn.edu. That's extension.umn.edu. If you have questions for us, comments about the show, or ideas about what you would like to hear, send them to themoosroom@umn.edu. That's T-H-E-M-O-O-S-R-O-O-M @ U-M-N dot E-D-U. One more time again, thank you for listening. Come back for the next episode as we talk to Kirsten a little more about what she's been doing with Brad and her master's thesis.
Kirsten: Very cool. Very neat.
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