- Welcome, everyone, to Wednesday Nite @ the Lab. I'm Tom Zinnen. I work here at the UW-Madison Biotechnology Center. I also work for the Division of Extension Wisconsin 4H. And on behalf of those folks and our other co-organizers, PBS Wisconsin, the Wisconsin Alumni Association, and the UW-Madison Science Alliance, thanks again for coming to Wednesday Nite @ the Lab. We do this every Wednesday night, 50 times a year. Tonight, it's my pleasure to introduce to you Jennifer Van Os. She's a professor in the Department of Animal and Dairy Sciences. She's gonna be speaking with us about giving dairy cows a voice through science. She was born in Champaign-Urbana and she went to Uni High School there on the campus of the University of Illinois. She went to Harvard and got her undergraduate degree in psychology, and then went to the University of California, Davis to get a PhD in animal behavior. She postdoced at the University of British Columbia in Vancouver and then came to UW-Madison in 2018 to be on the faculty in the Department of Animal and Dairy Sciences. Looking forward to this talk tonight. Would you please join me in welcoming Jennifer Van Os to Wednesday Nite @ the Lab?
[audience applauding]

- Thanks so much, Tom, for the introduction, for having me. I'm thrilled to be here tonight and appreciate everyone who's joining us, either here in person or tuning in otherwise. So as the introduction mentioned, I'm an assistant professor in the Department of Animal and Dairy Sciences here on campus, and I also am an Extension specialist in dairy cattle welfare. So it really is truly a dream job to be here in America's dairyland, to study dairy cattle. It really is the most amazing place to be, not only because we have so many dairy cows, but so many passionate dairy farmers, many of whom are alumni of UW-Madison and have gone back into the industry. So as an Extension specialist, when I arrived here five years ago, I went around to dairy producer meetings and I visited farms with colleagues who had been more established with Wisconsin's dairy industry to talk to farmers and try to understand, first of all, what do they think animal welfare meant, so we could get on the same page, and what were they proud of when it came to animal care? But also, what were the challenges they were facing so that I could make sure that the research I do in my lab is applicable to the state of Wisconsin's dairy industry? And so that's why I'm showing the picture here. This is the picture of me on a Wisconsin dairy farm, about 45 minutes' drive from here, where I was trying to solve some practical problems that they had with their ventilation system. 
So I'll talk a little bit about that later.

So I like to say that I don't have a traditional teaching appointment here on campus, even though I do work with our undergraduate students. But I do my teaching in the field and I also do my learning in the field because it's essential that the research we do doesn't occur in a vacuum and we don't just have these fanciful ivory tower ideas that aren't applicable to the industry. But above all, I think it's not only important to talk to the farmers to make sure that the research addresses their needs, but we need to talk to our animals. And so that's why I titled my talk, "Giving Cows a Voice through Science. " That's the unofficial motto in my lab. And so through this talk, I'll take you on a journey so that hopefully, you'll understand what I mean by that. So to start with a little bit of terminology, I think animal welfare is something that almost everybody has some kind of notion of. But my goal today is to show you how we study this scientifically.

So frameworks that we use in the field of animal welfare science, as well as the different techniques that we use to give cows a voice and understand what they need to experience good welfare. So if we break down the word welfare, we're asking how well an animal is faring. So an animal can be faring well, an animal can be faring poorly, or somewhere in between. It's a spectrum, and it refers to the animal's status. And so that's why you can see it's actually the downstream outcome. And what happens upstream is the care that's provided by the humans that are caring for these animals. So in this case, we're talking about dairy farmers. So dairy farmers are the ones who are providing the housing environments, using certain husbandry practices, and directly interacting with the animals on a daily basis. So when we talk about animal care, those are the inputs into the system and the actions that humans take. And then one of the outcomes is animal welfare or what the animal themself experiences. So to bring this back to what I see my objective in my job is, is to conduct integrated research and extension projects. 
So what I mean by that is I like to conduct very applied research. I think basic science is absolutely essential. You hear a lot about that here week to week. But what keeps me going is the idea that the knowledge that we can gain is useful to the dairy industry and for improving the lives of animals. And so I integrate that with my extension outreach to make sure that that research doesn't only end up in a library and is used by other scientists, but also gets out there and can hopefully help farmers and help dairy cows. And so the next step after conducting this research and doing extension outreach is to help us improve our understanding of dairy cattle welfare. What is it that dairy cows or calves need to have a good quality of life? And then that can inform best practices for the dairy industry that's founded on the latest scientific evidence.

And so when I talk about best practices, what do I mean by that? So this can really vary. From region to region, there are different regulations. In some cases, those can be legislated. And in other areas, these standards are determined in different ways. So here in the United States, there is a program which I think a lot of people outside of the dairy industry might not have heard of, but it's called FARM, which stands for Farmers Assuring Responsible Management. And this has been around for a while, but it's evolved over time. So when it started over a decade ago, it was a voluntary dairy producer education program similar to what's called Beef Quality Assurance or BQA, which is a rough equivalent in the beef industry, but now these programs have diverged and they have a different sort of model, but they are funded by what's called the Dairy Checkoff. So every time you buy a dairy product, a small portion of those proceeds goes to this national program that funds dairy marketing, but also this program called FARM. And so with Farmers Assuring Responsible Management, there are different pillars. So this has expanded and now includes things like environmental stewardship or workforce development to help dairy farmers develop their employees in terms of their professional development.

But the original goal of the FARM program was what's called animal care. And so this is their flagship program. It's still going today. And as we speak now, 99% of dairy farms in the U. S. participate through the co-ops or processors to which they sell milk. So essentially, it functions as a way for farmers to maintain their market. And so it establishes this uniform standard that almost all dairy farms in the U. S. agree to adhere to. And again, this is just a minimum bar. So farms can go above and beyond if they choose to, but it's a way for the dairy industry to proactively say, as a profession, "We agree that we all need to treat cows a certain way at minimum, and we can also do even better." So this is just one quotation taken from the website of this program, which is that it aims to raise the bar for the entire U.S. dairy industry by establishing dairy animal welfare management guidelines. So there is a booklet; it's the manual, and it's publicly available freely online. You can go see, it's about a hundred-page PDF document. And this is updated on, normally, a three-year cycle. Because the pandemic, it's offset a little bit. So we're currently in what's called version four of the FARM program. And then version five will go into effect about a year from now.

So I sit on what's called the Animal Care Task Force. And so this is the committee of different people across the U.S. that includes academics, welfare scientists such as myself, veterinarians, dairy producers, and representatives from these co-ops and processors. And it's important that we have this diversity of viewpoints and diversity of expertise so that we can make sure that these requirements are science-based, but also practical and achievable for the dairy industry. And one of the mottos of the FARM program is continuous improvement. So continuous improvement in terms of animal care practices used on the farm. So encouraging this bar to always grow higher as we learn more and more about animal welfare science, but also continuous improvement of the program. So acknowledgement that there is kind of a learning curve in terms of establishing a national standard and trying to make this program more and more rigorous. So I just wanna point out that the work that I do, it isn't just idealistic. It's not just me out there alone. There are other welfare scientists, veterinarians, people who study animal health, animal welfare. And our goal is to make sure that this information is accessible and that the expectations that we have of farmers are grounded in science, but also are informed by the farmers' voices as well.

But going back to my lab's motto, we seek to give the cows a voice through science. I think it really comes down to that because cows are different from humans. So I think it's important that we not just anthropomorphize, which means projecting what we as humans think is good or that we would want onto cows. I think that that can be a way to generate hypotheses. But we have to remember that different species are different and that cows needs aren't necessarily the same as that of people. So when we think about understanding the animals, we can use different scientific disciplines. So what I've shown here is different people examining a cow. And so you can collect these traditional production measures. How much milk is a cow producing, what kind of components in terms of fat and protein. And I think that that is important from an economic perspective since dairying is a business. But it also is important to understand other aspects of the cow holistically. So this can be the underlying physiological mechanisms, which is what many of my colleagues in the Department of Animal and Dairy Science study, but my training from my PhD is in animal behavior. And so I think it's important to observe the cows and give them opportunities to tell us, even though they can't speak English, we may eventually have some kind of instantaneous Moogle translate device that can let us really speak cow. But essentially, I see it as my job to ask questions in a clever way so that we can infer what the cow is telling us. So I have a two-year-old daughter, and one of her very favorite board books is called How to Speak Moo, and it's very cute. And so on every page, there are different kinds of moos. There's loud ones, soft ones, jiggly ones, whatever. But I think that this is a nice shorthand to explain what it is that I'm trying to do. We're trying to learn how to speak moo. Since cows can't speak to us in the way that we can understand, we need to make it easy for them to express what it is that they need.

So what I'm gonna do now is explain to you some of the scientific frameworks that we use for studying animal welfare. This diagram represents what's called Dr. David Fraser's three circles. So Dr. Fraser is my academic grandfather, meaning he was my PhD advisor's PhD advisor. And he's a lovely human being and also absolutely inspirational. So he came up with this framework, and there are other ways of thinking about animal welfare, but what I really like about this is that it captures that there are these different interests to consider when we're talking about animal welfare from a holistic perspective. So the circle at the top, I've labeled health, but I think a more nuanced way to think about it is the animals' bodily functioning or physical or physiological functioning. So if this were a wild animal, we would be thinking about their fitness. Are they able to survive and reproduce? And when we're thinking about farmed animals, we might be examining aspects such as health. So does the cow have injuries or does she lack injuries? Does she have some kind of disease state or is she healthy? How is her reproductive ability? How is her milk production? Or for a younger animal, what's her growth? And so all of these things are definitely important. I think it's very intuitive and obvious why, and there are decades of animal science and veterinary science research into understanding this aspect of animal welfare.

But I think it's important to note that animal health and animal welfare are not synonymous. So no, I'm not a vet. Sometimes I wish I was. There are lots of things that I can't answer because I don't have that kind of training. But what you can see is that good health is necessary for good welfare. It's a component of it, but it's not sufficient. We have to think about other aspects of the cow's quality of life to really understand her welfare. So what I'm gonna point to then is this circle on the lower left corner that's blue. And so I've labeled this with the shorthand as the cow's feelings. And I think sometimes calling it that can get a little sticky depending on who you're talking to, but that's the shorthand. The scientific jargon is the cow's affective state. So this means her emotional state or subjective internal mental experience. And I think this is really key and it's why we have the entire field of animal welfare. So what is the difference between farm animals and farmed plants when we talk about other aspects of agriculture? And it's that plants are not, as far as we know right now, sentient. So there are people who study the biological functioning and health of plants. There are plant pathologists. It's very important. But we're not concerned that plants can suffer. But we are concerned that farmed animals can suffer. And so through decades of scientific research now, we have been validate that farmed animals, including dairy cows, are able to experience positive and negative affective states.

So again, we're not trying to anthropomorphize. I think there's been really fascinating research on species such as primates or elephants, looking at these very nuanced emotional states that can seem very human-like. So you may have seen videos of monkeys who seem like they're jealous of other ones. That's not what I'm talking about here. So when we talk about dairy cattle, what we need to acknowledge is that there are very negative states that people might describe as suffering. So this can be pain, fear, stress, and these are things we want to avoid. But on the flip side, we know that they can experience positive emotions, too. So this can be emotions such as comfort or contentment or reward, and that we want to promote the opportunity to experience these positive affective states. So of course, one of the things that can influence an animal's affective state is her health status or her biological functioning. If she's not feeling well physically, she might not be feeling well emotionally. But that's where this third part of the Venn diagram comes in because we know that there are things other than just, I put that in quotes because obviously health is important, but there are things other than just an animal's health that can affect her subjective experience and her overall quality of life. And so as a shorthand, I've labeled this "behavior." And I think it's better described as the ability for an animal to perform species-relevant natural behaviors or important natural behaviors. This doesn't mean all natural behaviors, but ones that lead to a positive affective state or minimize negative affective states.
So what do I mean by that? There are natural behaviors that are not necessarily something that the animal wants. And for example, that could be being chased by predator. That is natural. A lot of animal have anti-predator responses. It doesn't mean that if in captivity, they don't have a chance to express that, then they have a negative affective state. But on the flip side, there are certain behaviors that are relevant for a species, that are important for them to perform. And if they don't get that opportunity, they can experience negative emotion such as frustration or stress. And so I'm calling this behavioral well-being just as a reminder that it's not just physical health, but also this emotional health. Okay, so now you've had animal welfare 101. We've talked about Dr. Fraser's three circles. And again, the reason I like it is because I think it really captures this holistic idea of animal welfare to help us think through which aspects of welfare are certain management practice addressing. Are we providing an animal with good biological functioning and physical health, but missing out on opportunities to allow her to express important behaviors? And it helps remind us to think about these three different aspects. 

Many of you may have heard of a different framework. So how many people here have heard of the five freedoms? That's totally fine. So what you might have seen this if, say, you're somebody who is already interested in animal welfare and you're concerned about where your food comes from, your favorite restaurant chain or grocery store may have an animal welfare statement on their website. And if they do, there's a very high chance that what they're gonna show is that they believe in the five freedoms and expect their, say, dairy suppliers to adhere to the five freedoms. So this is very historically important. And so the five freedoms are that the animals should be free of hunger and thirst. These are negative emotions, which is why I've color-coded them blue. Freedom from discomfort, again, a negative affective state. And then freedom from pain, injury, or disease. So pain is a negative emotional state. Injury and disease threaten the animal's biological functioning. And then freedom to express most natural behavior. Again, there's this caveat of most, because not all natural behaviors are desirable or important. So you can see I've color-coded that in green. And then finally, the freedom from fear and distress. Again, negative emotions. And so you can see with the five freedoms, they are touching upon all three of Dr. Fraser's circles. And you can see they're also heavily weighted towards the animal's affective state because again, it comes down to, what is the cow's quality of life? What is she experiencing subjectively? But I like Dr. Fraser's circles because you can see it's color-coded. It's very easy to organize your thoughts using the three circles. 

So coming back to this idea of how do we give cows a voice? I think it is easy to objectively measure things like biological functioning. It is more difficult to measure these other aspects. So what is the animal's subjective mental state? What kinds of behaviors are important for her to perform? So what I'm gonna mainly talk about today is the green circle. How do we understand what a cow wants? And so what we can do is provide opportunities for them to tell us, and we can then measure and quantify either what it is that a cow prefers and what is important to them, and how important is it. And by allowing them to express those things, we can gain some insights into their behavioral needs and improve their welfare by working opportunities into their environments for them to express those behaviors. So what I'm going to talk about now is these two major techniques that we often use in animal welfare science. So the first is called preference testing, and it's pretty much exactly what it sounds like. It's a way to allow the animal to vote with their feet. And so there are different ways that we can evaluate preference in scientific studies. 

So some of them can be short-term and somewhat contrived. So we have a tool that we call the Y-maze. And this can be very small in the case of a mouse or very large in the case of a cow. And it's exactly what it sounds like. So the animal starts at the stem of the Y, and then they're presented with two different choices. And then you can quantify which option they choose more frequently. And so the animal learns what the options are, and then they have repeated chances to make this choice. And then you can quantify, do they choose option A significantly more often than option B? And that would allow you to infer that they prefer option A. There is another way to conduct preference testing in what we call the animal's home environment. So again, for a mouse, this could be in their cage or for a cow, it would be in the pen or the pasture in which they live. And so you can offer them different choices within their home environment. And over time, you quantify how often they use a certain resource or how much time they spend using it compared to another one, say, of equal size. And so you account for chance. How much time could they happen to be observed in that area if they didn't actually care or have a preference. And then you can quantify, did they spend significantly more time there than would be expected by chance? And then infer their preference.
So I think preference testing is very important. It's very common. It's a technique we use in our lab a lot, but there are some limitations. So preference testing tells you a ranked choice among the options that you present. So first, you have to make an educated guess. Are the options you're presenting even relevant? And all that you're inferring is the rank choice. You know, they choose option A more than option B, or they spend more time with option A more than option B. But what it doesn't tell you is the valence. So by valence, I mean is it something positive, neutral, or negative? And sort of to what degree? And so what I'm showing here with these emoticons is the situations that can happen, but you can't actually discriminate between these with preference testing. So the first option, it could be that you've presented an animal with two choices that both have a positive valence. And so I'm calling this icing on the cake. So it could be in our free ice cream example. Maybe you're somebody who likes both the vanilla and also the orange custard with the chocolate chips, and you just happen to like the one with the chocolate chips more, so that's what you chose tonight. Or maybe you're somebody who took both. But in any case, that's just icing on the cake. You like both, but you're just gonna take the more preferred one. Or it could actually be that the animal is discriminating between opposite valences. So it could be that one option is something desirable, that is preferred, and the other option is actually something negative or aversive. And so they would choose option A because it's something positive and they're avoiding option B because it's aversive.

And the last scenario that I'm outlining here is what I'm calling the lesser of two evils. So maybe, actually, they don't like either option, but they don't have a choice and they can't avoid both. So say in a Y-maze test, they have to go and pick one or the other within an allotted time. And so they're just choosing the lesser of the two evils or the one that's less aversive. So the problem with preference testing is you cannot distinguish between which of these three scenarios is going on in terms of what's happening internally for the animal. Why are they making the choice that they're making? And so this is where just a preference test alone isn't enough. I think it's a really excellent starting point and it's a very powerful tool. But then other research is needed to understand why is the animal choosing that? Is it something that they find desirable that they're actually motivated to obtain, or are they trying to avoid something?

So there are other techniques that can complement preference testing. And I'm just gonna talk about one of those today. And that's called motivation testing. And so this draws inspiration from consumer literature. So when we look at human economics, we can make some analogies that have informed some of the interesting techniques that we've applied to animals. So if this was a test with human subjects, you might play an economic game where they give you real money or fake money and ask you how much would you pay for a certain thing? And the more you're willing to pay, the more important we would infer it is to you. So if you're willing to pay more, it's more desirable. And we can translate this into a language that animals can understand. So in the case of certain animals, for example, dairy cattle, you can ask them to push weights. So you can put weights on a gate and you increase the amount of weight. And so they have to exert more physical effort to obtain a certain resource. So now they're paying an increasing price. Another classic example is asking an animal to push a button or a lever repeatedly. So I think people have heard about this with lab rats or lab mice, and we've done the same thing. We've trained dairy calves to push a button repeatedly. And so you increase the price by asking them to push that same button more and more to obtain the same resource. And another way is to ask an animal to navigate obstacles. So literally you can put a moat or you can put something they have to climb over. So there are other ways to impose this price. So the logic is that if a resource or opportunity to perform a certain behavior is important to an animal, then they'll be motivated to gain access to that resource or to perform that behavior. And so if they're motivated, they should then be willing to work harder to gain access to that resource or to the opportunity to perform that behavior. And so they would continue to pay that price even as the price increases.

So the way we graph this out is what's called consumer elasticity of demand. So again, it draws from these economic theories and applies it to animal behavior. So what you're seeing on the x-axis is increasing price. So as you go to the right, you're requiring people to pay more money or push heavier weights, press the lever more times, et cetera. And then on the y-axis, again, it's unitless, but it's increasing or decreasing willingness to pay a certain price. And so the line that I have here right now is illustrating what's called inelastic demand. And we can classify things as essentials if you see this pattern of relatively inelastic demand. So that line doesn't have to be flat, but it's relatively flat. So you see that as the price increases, the demand doesn't decrease that much. And so the example I've put here is an egg because it's something that I think many of us have experienced recently. So as a result of the avian flu, egg prices went through the roof and we went from paying less than $2 a dozen to, like, $12 a dozen at one point. And my family continued to buy eggs. We just maybe ate fewer at a time and stretched it out a little bit further. So our demand for eggs was relatively inelastic. We saw this as an essential or staple in our household. But yeah, so as an example for how you would evaluate this in dairy cattle, we have what we call a reference. So something that we know is really inelastic for them. So in the case of dairy cattle, we know that they're highly motivated to gain access to fresh feed when they're hungry. It seems intuitive, but this is something that we can impose in a testing scenario. So we can, say, deprive them of feed for two hours so that they get a bit hungry, and then we know that they'll be willing to pay this price. So even as the price of gaining access to feed increases, we know that they'll pay that price because they're hungry. And so they'll do the work to obtain access to fresh feed.

Okay, but shifting to a different example line now. This blue line, I'm contrasting this with the one I showed you for inelastic demand. So this is illustrating the concept of elastic demand. So you can see that as the price increases, now the willingness to pay goes down much more steeply. And so you could consider something to be more of a luxury, less of an essential if you see this steep decrease in demand as the price increases. So the analogy I've put here for me would be concert tickets. So back in the day, I used to go to a lot of rock concerts. It's something I enjoy a lot. But nowadays, not only has the price gone up, but also the fees on top of those. And so for me, I've decided to go without. I don't go as frequently anymore. I'm not willing to pay that price, even though it's something I enjoy. So what I'm gonna do now is walk you through an example of how motivation testing can be applied to understanding what's important to dairy cattle specifically. So sometimes, dairy cattle are housed in environments that lack some opportunities to perform certain natural behaviors. And when that happens, if an animal has a highly motivated natural behavior that it would normally desire to perform and it's unable to do so, she can experience negative affective states. So this can be boredom or frustration. And this can result in the animal performing abnormal behaviors, sorry, abnormal behaviors. And that's something undesirable. It's an indicator of possible negative welfare.

So as an example of a natural behavior that cattle are highly motivated to perform, we can talk about grooming. So there is a way to give cattle opportunities to perform this natural behavior indoors. So if you house cows outdoors, they will often rub against fence posts or trees or other objects to groom themselves. And when they're indoors, this can translate into them rubbing on objects in the pen that's maybe not so desirable. And so a lot of dairy farms do provide these rotating mechanical brushes. And these aren't just repurposed from car washes, although they can be. These are actually custom-built for dairy cows. And there's many different manufacturers on the market now that market these for dairy cows. And the reason is several-fold. So first, there is a benefit for the cow's biological functioning. So by grooming themselves, they can remove ectoparasites, they can remove dead hair. It's something that improves hygiene and cleanliness. So a lot of dairy farmers were originally drawn to this idea for milk quality purposes. So they want to have clean cows and good hygiene on the farm, but it's also something that research has shown is important for their welfare in terms of addressing this desire to perform a highly motivated behavior.

So this is the photo taken at the University of British Columbia's Research Dairy where I did my postdoc. I'm not the one who did this study, so I'm just giving you an example of one of the studies that they did. But they used motivation testing to try to quantify how important is it for cows to have access to a brush. And so the graph I'm showing you here should look somewhat familiar. It's an example of this consumer elasticity of demand. It's also called a survival curve. And so what you're reading is, it's sort of an inverse, but on the x-axis, it's the amount of weight attached to a pulley system that was attached to a gate. So the units there really aren't important. What's important to know is that they increased the amount of effort that it took for the cows to push open that gate. And then on the y-axis, what you can see is the proportion of cows that were willing to push. So in the beginning, when there was no weight on the gate, you can see it's at 100%. And then as the amount of weight increases, then fewer cows are willing to push. 

And so they had three treatments in this experiment. One was an empty pen as a control. So cows had to push this weighted gate and they just got access to a pen with nothing in it. And they could see before they entered that there was nothing in it, but they wanted to just compare our cows pushing just for kicks. And then they had this positive control treatment. So that was what I mentioned earlier. It's something that we know is inelastic. So the access to fresh feed after two hours of feed deprivation. And then the third treatment was that rotating mechanical brush that you saw in the photo. So what the graph is showing you is that this black line here is the empty space. So you can see demand dropped off quickly as the price increased. And then these other two lines, so they actually had two different chances to access the brush. So that's the yellow and the red. And then the blue is the fresh feed. So you can see those curves are pretty much neck and neck. So the cows were more willing to continue to push as the price increased compared to accessing an empty pen, but they were equally motivated to access fresh feed when they were hungry as they were to access the brush. So just to sort of visually summarize that, I'm putting up the curves that I showed you earlier just as examples. And so you can see the demand was not perfectly inelastic when it came to the brush or the fresh feed, but it was much more elastic for the empty pen than it was for these other two resources. So what they inferred from this study is that cows do care a whole lot about access to this brush. They care just as much as they do to access fresh feed when they're hungry, which was the gold standard they were comparing against. So I think that this is a really great example of how we can ask cows questions about what is important to you and how important is it.

I wanna shift to talking about a little bit of the work that we've done in my lab. So we've looked at other age classes as well. So what I'm showing here is a picture of some heifers. So these are future milking cows and they've already been weaned off of milk. And now they're in the growth phase, but they're not producing, lactating cows yet. And we wanted to look at ways to give this age group access to brushes in a simpler, maybe more affordable fashion because these large, fancy rotating brushes cost thousands of dollars. It's a big investment. And a lot of dairy farmers do invest in their cows and provide them, but we wanted to see if there was a practical lower barrier option for them to enhance their animal care without this huge financial burden. So we went to the hardware store and we bought some deck scrub brushes and we mounted them on the walls. And we wanted to see how these weaned heifers would respond. So one of the things we looked at was how quickly did they approach them? Because dairy cattle are, by nature, very curious, but they are also sometimes a bit fearful of novelty. It's called neophobia. They have reason to be skeptical because they are prey animals. And so sometimes, when you put a new object into a pen, they will avoid it; they'll stare, but they'll kind of avoid because they aren't sure if it's a threat. But what we found was that for these heifers, they had never seen a brush like this in their lives. But on average, it took them less than four minutes to start using them. And some heifers started using them within eight seconds. So it was something that they were just drawn to and they started using them right away.

And what I'm not showing on this slide is that we also had an element of a preference test. And so we had mounted these brushes in different orientations, either vertically or horizontally. We had bristles of different stiffnesses because some manufacturers market softer bristles for calves, softer and gentler. We wanted to know, do the calves actually care? And what we found was no preference. But in this case, we actually thought that the lack of preference was informative because it meant that dairy producers have flexibility in how they provide this resource to the calves. So our message was, it actually doesn't matter which direction you mount it, it doesn't matter what kind of bristles you buy, they will use them. And so in this case, the lack of preference was actually useful information. And another thing that we found was that this younger age group used these brushes in different ways. So with the rotating brushes, cows are primarily using them for grooming, but with these simpler brushes that don't rotate, what we found was that the younger animals were, in fact, grooming themselves as expected, but they were also doing a lot of what we called oral manipulation. So they were licking the brushes, chewing them, and exploring them with their mouths. And we thought that that was really interesting. And that potentially, it meant that this same resource could provide opportunities for them to perform different types of natural behaviors. So we haven't explicitly looked at motivation for this specific type of brush, and no studies have compared cows' preferences between the two types. But we thought that this was interesting and it showed that they could have multiple benefits. And sorry, on this slide, it does talk about the lack of preference.

So I'm gonna shift gears and talk about a different example of another topic that we look at in my lab. And this is the topic I began exploring during my PhD in California, and this is alleviating heat stress. And so today, with it being almost 90 degrees, I think it is the perfect time to talk about it, especially in the comfort of an air-conditioned room with free ice cream. [audience chuckling] So with thermal stress, it's something that we know affects the animal's biological functioning. There are enormous economic impacts because when cows are heat-stressed, they produce less milk. It's an adaptive mechanism because milk production takes an enormous amount of energy. So they produce a lot of metabolic body heat as a side effect. So when cows are heat-stressed, they produce less milk, and that's protective to them because now they produce less body heat. It's a way for them to alleviate that heat stress naturally. But again, that's bad news economically. And we also know that it can affect their welfare in other ways. So cows respond to thermal stress with this subjective feeling of discomfort, and they tell us this through their behavior, and this can disrupt their normal behaviors. And so if we're thinking about these different circles of welfare, heat stress is a serious concern in terms of the animal's welfare from all of these different perspectives.

So I'm showing this graph that's updated through the end of 2022. And what it's showing, I'm sorry, it's a bit small, but the redder colors mean that the temperatures were warmer compared to what's expected. And the cooler colors indicate that the temperatures were cooler. So what you can see is there's a lot of red. So the most intense red means that that's the record warmest ever recorded. And what this information is showing on average is that 2022 was the sixth-warmest year among all the years on record since 1880. And so we've had this happen where now it's not just a one-off, it's become a pattern. And so from a dairy cattle welfare perspective, we are increasingly concerned about the burden that heat stress is placing on our cows. And we have every reason to expect that it's going to be a continued, if not increasing, welfare concern in the future.

So this is gonna sound like a digression, but it's not. People often ask when they find out that I'm an animal welfare scientist who works on dairy cattle, they want to know if it's better to house cows outdoors on pasture or inside in a barn. And the answer is both, actually. So when you give cows a voice and you ask them what they prefer, cows choose to be in both environments. So from the cow's perspective, it's not that they always wanna be on pasture or always want to be in a barn, or never wanna be in a barn, or never wanna be in pasture. It's context-dependent. And so that's one of the messages of this next graph I'm showing you. So these are two studies that were done in Canada, not by me, but at the University of British Columbia. So the climate is not terribly different from here. You know, it's moderated a little bit because it's sort of close to the coast, but they do have the extremes in our temperate climate. So they have snowy winters. They have relatively warm summers. Maybe not even as warm as here, but what you're seeing is on the x-axis, we have a temperature humidity index. So it's an index that combines air temperature, dry bulb temperature, and relative humidity. So the higher the temperature humidity index value, the hotter it feels. And so you can have a relatively cooler temperature with high relative humidity that feels hotter than a high air temperature with a lower humidity. So it accounts for that. And on the y-axis, what you're seeing is the percentage of time that cows were spending on pastures. So they were housed in a barn and the doors were open. So they had free choice for how much time they wanted to spend inside the barn and outside on a connected pasture. And so what you can see is that cows were never spending 100% of their time outside or inside, and this was just during daylight hours in both studies.

And the second thing that you should see is there was this negative linear relationship. So the hotter it was outside, the less time cows spent outside on pasture. And so what this is illustrating is that their use of those environments was context-dependent. So what we think was happening was that the cows were staying inside during the peak heat of the day because the barn provided shade, which is something that we know is very important to cows. What these graphs aren't showing you, but these studies included, is patterns over time of day. So cows actually spent the vast majority of their time outside in pasture at night. And interestingly, they weren't grazing. So they were provided a total, what's called a total mix ration. So they had all the nutrients they needed indoors if they chose to eat indoors, but they went outside at night to lie down. But during the day, they were primarily inside, especially as it grew hotter. And so when we're talking about thermal stress, I think this is really important to understand that cows can tell us what they need.

And so this is why we shouldn't anthropomorphize. So yesterday, it was 87 degrees outside. I was at the Memorial Union Terrace and I saw undergraduates sunbathing. And I am not heat-tolerant. I wanted to sit in the shade. And so I think for a lot of people, they would think, you know, "Cows wanna be outside on pasture. They want to feel the sun on their backs because that's what I like. I wanna be out sunbathing." And that's absolutely not the case for your average dairy cow. They are what I call metabolic athletes. It takes a lot of physiological work to produce that amount of milk, so they start to feel hot at a lower threshold than we as humans do. And so again, this is why it's so important to give cows a voice. So we know that cows are highly motivated for shade. So the study I'm going to talk about was done by a collaborator in New Zealand, and what they did was they set up a trade-off. And so instead of having cows push weights because physical exertion generates body heat, they had to find a different way for cows to pay a price. So we know that for dairy cows, they need to spend approximately half of their day or more lying down; it's how they rest. So unlike horses who sleep standing up, cows actually do need to spend a great deal of time lying down. That's when they do a lot of their ruminating and chewing their cud and digesting. 

So in this study, what they did was they built a structure on the ground. It was kind of a grid, so it was uncomfortable for cows to lie down. So they essentially were forced to stand up for 12 hours straight. And then they gave the cows a choice. So now they could go lie down, but that area was still in the sun. Or they could continue standing up and do so in the shade. And what these cows chose to do was to keep standing, even though they were fatigued and they need to spend at least half their day lying down, they chose to keep standing up because that's how important the shade was to them. And this same research group in New Zealand, and I should say that they house their cows on pasture. So this is where this question of shade access is so important because they're not typically housed inside of a barn. So in a different study, they use preference testing. So again, these techniques can complement each other. And in this study, they set up a Y-maze. And the cows were exposed repeatedly to three different options so they could understand what they were choosing. But then they were offered the choice between only two options at a time so that they could rank order these preferences. 

And so the three different choices were a shade structure, no shade, so just ambient conditions and direct sunlight. And then sprinklers that would shower the cows with water, which would help them cool down. But these showers were not shaded. And so they also measured the cow's thermoregulatory responses. And they found that when the cows were unshaded, they accumulated heat. So their thermoregulatory responses showed that they became even hotter over time. When they were shaded, it kept them from gaining heat from solar radiation. But when they were soaked with water, they actually actively cooled down. So the water soakers were the most effective when you looked at the biological functioning perspective, but that's not what the cows chose. And that shows again how important shade is. So when they were comparing the choice between the shade and the sprinklers without shade, cows chose the shade significantly more often. And of course, they chose the shade more than the direct sunlight.

So when you ask the cow, she didn't necessarily choose the most effective option, but I think the option that made more sense from an evolutionary perspective. So we do see cows in naturalistic settings that will wade, but when we observe their behavior in rainy conditions, they often show this kind of avoidance behavior. And so even though it's more effective, it's kind of hard to get them out of that sort of evolutionary context. So shade is something that's so relevant to them, it's something that they seek out. We have to make sure to provide it. And so the take-home message here is to avoid trade-offs between important resources. So we know that water soakers are effective, but shade is also effective and it's something very relevant to the cows. So when I conducted my PhD in California, I took that idea and I then gave cows a choice between eating under an area that had just shade or an area that was also shaded, but now had water soakers. And in that case, the cows did prefer the combination of the shade and the sprinklers. So it's not that they don't know what's good for them, it's just when you force them to choose, they will choose shade.

And so what this graph is showing is I just have 24-hour air temperature in degrees Celsius, so not the temperature humidity index because in this environment, the relative humidity was so low that it didn't make any difference. And then what you're seeing here on the y-axis is the percent of time they spent in the option that had the combination of shade and sprinklers. And then there's a dash line here at 50%. So what you can see is that when these resources were combined, the cows were spending the majority of their time under the shade with the sprinklers and not just the shade alone. So as long as you combine the resources, the cows do prefer that. And that magnitude of preference increased in warmer weather. So when I moved here to Wisconsin and I was talking with Wisconsin dairy farmers about their concerns around animal welfare, a lot of them did bring up heat stress. They know that even in this continental climate where we have long, cold winters, that heat stress is still a concern in the summer. 

And although some farms in this region do use water soakers, a lot of times, they had questions about ventilation. So this is something I didn't work with in California. There, the barns tend to be open-sided. It's a different climate. It's a different system, but it got me thinking about how to address some of these concerns. So going back to my very first slide showing the inside one of these Wisconsin dairy barns, I got a lot of questions about, well, "How exactly are we supposed to calibrate our fans?" So it's very common that dairy producers have fans installed, but just the presence of a resource doesn't mean that it's effective. So my analogy is, if you walk into somebody's home and you see that they have a treadmill, that doesn't necessarily mean that they're physically fit. They could be using it as a clothes drying rack. And so you actually have to measure some outcomes to know if that resource is delivering the intended effect. And so that is what we did here when we were evaluating the use of fans or other mechanical ventilation systems in dairy barns in Wisconsin. 

So what we did here was we calibrated the fans to deliver a specific airspeed as measured at the cow's resting height because there can be a lot of problems with the fan installation, where even if you have a very powerful device, if it's not aimed correctly, it's not gonna reach the cows and deliver this intended effect. And so it sounds really obvious, but this was the first study that looked at calibrating the air speeds at the cows' resting height to provide this fast-moving air where they need to spend at least 12 hours a day lying down. So previous heat stress research had found that methods such as fans or water soakers could do things like improve milk production during periods of heat stress, which is really important, and that's a component of welfare. But no previous work, including my own in California, had ever been able to find a way to encourage cows to spend enough time lying down in heat stress. So instead, you would see this characteristic negative linear response, where as the temperatures got hotter or temperature humidity index got higher, cows would spend less time lying down. And we know this is problematic from a welfare perspective because cows want to spend half the day lying down, but they were standing up to dissipate heat and compensate even when they had these very effective water soakers. And we think it's because, again, if we think about their evolutionary history, they're responding to certain cues in their environment. And so when they're getting sprayed with water soakers, that's not where they're lying down because you don't wanna make the bedding wet. That's a milk quality issue. So instead, we thought they might respond behaviorally to this fast-moving air over their backs if we target these fans correctly. 

And so that's indeed what we found. But instead of showing you graphs, I think in this case, a picture is worth 1,000 words. So this is just a snapshot in time. But these two pictures were taken one minute apart at about 2:00 PM on a very hot day. And so what you can see in the top picture is an example of our control treatment. So in this case, the fans were turned off and it was just the prevailing winds coming through the barn. And only 5 out of the 16 cows in this pen were lying down and resting in their stalls. And all of the rest were bunched around the water troughs, which is a natural behavioral response during times of heat stress. But in the bottom photo, you can see in one of our fan treatments, we had calibrated these fans to deliver high-speed air. So 2.4 meters per second at the height of a cow lying down. And there, 14 out of the 16 cows were resting in the stalls and the other two were eating. And that's normally a behavioral response that's suppressed in times of heat stress. So they eat less so that they produce less heat while digesting. And so this I think is really emblematic of the quantitative results we found in this study.

But heat stress doesn't just affect adult lactating cows. So adult cows are quite vulnerable to heat stress because they're producing milk and producing so much metabolic heat. But we also need to think about the younger age classes as well. And so what I'm showing here is a common housing system for young pre-weaned calves in our region. So they often are housed outdoors. And the reason for that is that it provides really good ventilation. So even though we have harsh winters, we often find good health outcomes when calves are housed in what's called these outdoor hutches because of this natural air exchange. What I'm illustrating here is a housing system that we used in our research setup, and I'm just calling it a calf duplex as a shorthand because it illustrates the fact that these calves had a social companion. So these two hutches were placed side by side, and they were connected by an outdoor fenced area. So the calves had two of these plastic igloos and then also this outdoor area that they could share. So they could choose to be together inside one of the hutches. They could choose to be separate if they needed some alone time, or they could be outside together.

And so this study was done by my PhD student, Dr. Kim Reuscher, who successfully defended her PhD yesterday. And she came from Texas where heat stress is always top of mind. And she had this passion for trying to better understand heat stress in dairy calves. And so she made this beautiful illustration here of how calves can gain heat from their environment. So with these plastic igloos, depending on the design, sometimes when the calf is inside, even though she's shaded from direct solar radiation, there can sometimes be this unfortunate greenhouse effect. That's not the case actually with the ones that are research dairy; they do provide shade and kind of hold that internal microclimate stable. But once the calf is inside, now she's generating body heat and that can cause the temperature inside the hutch to also increase. But this is something nobody had actually quantified before. And now in this calf duplex setup, calves have the animal welfare benefit of social companionship. But if they try to be inside the same hutch at the same time, now you have the heat of two bodies, perhaps exacerbating the experience of heat stress inside that environment.

And so what Dr. Reuscher did was she gave calves a preference test. And so they were housed with these two connected hutches, but one of them had additional passive ventilation. And so that's what you're seeing on the left. So this rear door here is actually so that the farmer can add additional bedding, but we had that propped open and then secured with a cable tie so the calves couldn't escape because we did have some that were escape artists. And then there were these additional portholes on the bottom that can be closed in the winter. So we don't want that icy-cold winter air coming in. But in the summer, you can open and provide this additional passive ventilation. And then the other hutch was not ventilated on the back. But what you see in this picture is there is an opening on the front for calves to come in and out. It's not completely sealed up. And each pair of calves had one hutch of each type, but the side was bound. So it's not that the ventilator was always on left and the nonventilated was always on the right. That was balanced between the pairs.

And so what I'm not going to show you, but I'll just tell you, is that this passive ventilation did manage to make that environment cooler. So even without calves inside, the air temperature was cooler inside just from better air exchange. And it also affected the calves' thermoregulatory responses. So we had a phase of the study where we standardized how much time the calves spent inside each type of hutch, whether by herself or with her social companion. And we did find that this passive ventilation mitigated their biological functioning, their physiological signs of heat stress. But what we're talking about today is giving the calves a voice. And so we also evaluated their preference for these different hutch types. So we did this at three different life stages. So this is their weeks of life. So four weeks old, six weeks old, or nine weeks old. And we looked at this for three-day periods within each of these weeks. And so with the reason we chose these time periods is because they represent milestones in the calves' development. So at four weeks of age, they're still drinking a lot of milk. They're on their peak milk allowance. But then by week six, they're beginning weaning. So they're tapering off milk and eating more solids. And then by nine weeks old, they're completely off of milk and they're only eating solids. And at the same time, they're getting bigger and their rumen is developing, and they're starting to produce more body heat. 

So what you can see is that when they were four weeks old, there's this dash line here indicating 50%, which would represent chance or no preference between the two hutch types. And indeed, when they were at that age, they spent about equal time in both the non-ventilated and the passively ventilated hutch. But then by the time they were six weeks old, and again, when they were nine weeks old, they developed a significant preference for spending time in the ventilated hutch. And they were often found there together. So even though we found that when two calves were inside the same hutch that did increase the heat load on the calves, the ventilation could mitigate that. And that's what the calves preferred. And so the calves were able to tell us that they were attracted to this environment that provided a more thermally comfortable place for them to spend time.

So just to wrap this up, the take-home message is that I think it really is important to give cows or calves or whatever species a chance to tell us what they prefer and what's important to them because by giving them a voice and learning this information, we can gain insight into what they need. So what behaviors are important for them to perform, what resources are important for them to gain access to so that we can improve their welfare from this holistic perspective. So of course, it's important to think about their health and their biological functioning. But when we're looking at welfare holistically and we're thinking about their subjective quality of life, what are they experiencing? Then we need to also consider this ability to perform these important behaviors. So I know that we'll have a bit of time for questions, but if anybody thinks of any, some other time, I always welcome you to reach out. Email is generally the best way to reach me since I'm not always by my phone. And so you can email me at jvanos@wisc. edu, and then I have a shortcut for my website. So if you've seen one that has cals. wisc. edu, it takes you to the exact same place. And so we have some resources there, some videos, some fact sheets, and I always welcome you to reach out. So thank you very much. 
[audience applauding]