Guests: Dr. Mary Beth Hall with the USDA, Dr. Paul Kononoff from the University of Nebraska-Lincoln. Co-host: Dr. Clay Zimmerman, Balchem. We continue our discussions on the new 2021 dairy NRC, now known as NASEM. This is a follow-up to our Real Science Lecture series of five webinars that officially unveiled the content back in September. We’ll be breaking down the feed intake and carbohydrates sections during this episode.
Guests:
Dr. Mary Beth Hall with the USDA
Dr. Paul Kononoff from the University of Nebraska-Lincoln
Co-host: Dr. Clay Zimmerman, Balchem
We continue our discussions on the new 2021 dairy NRC, now known as NASEM. This is a follow-up to our Real Science Lecture series of five webinars that officially unveiled the content back in September. We’ll be breaking down the feed intake and carbohydrates sections during this episode.
Dr. Mary Beth Hall discusses the changes in the dry matter intake equations in the new NASEM. She explains that there are two different dry matter intake equations, and those equations have new factors that give producers a much closer look at the diet and what factors will influence intake. (7:29)
Dr. Paul Kononoff discusses the new feed factor equations and using different forage decisions. He explains when using it for forages, the new equation will be very useful to producers especially with all the factors involved. He also discusses byproducts and his hope for them to be included for future equations once more research is done. (26:19)
Dr. Mary Beth Hall discusses the carbohydrate chapter. She explained the equations didn’t drastically change but they discussed the different types of carbohydrates in more detail and had a better understanding of starch and fiber. (30:40)
Dr. Paul Kononoff discusses the gaps that are possibly in the new NASEM for the next committee to work on in the future. He stressed the importance of reporting chemical composition of feeds and forages. This will not only give a better understanding to those using the current equations, but it will also help the next committee when deciding on changes to those equations in the future. (45:55)
As a reminder, we finish breaking down the new 2021 8th Revised Edition of the Nutrient Requirements of Animals in one more podcast releasing next week. Be sure to subscribe so you don’t miss any of the new episodes. If you’d like to pre-order a copy and receive a 25% discount, visit Balchem.com/realscience and click on the NRC series for a link and the discount code.
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Scott Sorrell (00:00:07):
Good evening everyone, and welcome to the Real Science Exchange. The pubcast where leading scientists and industry professionals meet over a few drinks to discuss the latest ideas and trends in animal agriculture. Tonight, we continue our discussions on the new 2021 Dairy NRC, currently known as NASEM. This is a followup to our Real Science Lecture series of five webinars that officially unveiled the new dairy NRC back in September. We'll be breaking down the feed intake, carbohydrates, and feed analysis and composition chapters during this episode. Hi, I'm Scott Sorrel, one of your hosts here tonight at the Real Science Exchange. Tonight, we welcome Dr. Mary Beth Hall who presented the feed intake and carbohydrate sections during the Real Science lecture series. Dr. Hall, welcome to the Real Science Exchange.
Dr. Mary Beth Hall (00:00:55):
Thanks for having me, Scott. Pleasure to be here.
Scott Sorrell (00:00:57):
Well, thank you for coming. And I understand that you are you're going to be our designated driver tonight. So Clay, that means Clay can drink a little more of his cider. Would you mind giving us a little bit of background about the process that was employed to create the sections of the new Dairy NRC that you presented during the Real Science lecture series? It's been 20 years since the last one, I'm sure that you and your team have put in a ton of time and effort these past few years.
Dr. Mary Beth Hall (00:01:26):
Well, I tell you what though we'll toss this back between Paul and me for answering that. When the committee first came together, there were a list of topics. I mean, some that we're used to seeing in the NRC, some not that were on the list of chapters of topics that they wanted to address. And those were parceled out to most of the committee members, and with the lead and with associate people on each chapter, and we proceeded from there. Some chapters looking a lot more like a literature review, and some chapters diving deep into the bowels of creating models and so forth that got brought together into the final models that will come out with this publication.
Dr. Paul Kononoff (00:02:14):
You know, I'd maybe just add, too, I think it's, it's important to recognize that this, if you look at the cover, it will be noted that it's a revised edition. And so really, you know, where the committee started off was looking at the previous reports that had been written, not just the 2001, but Mary Beth- I remember us even talking about the 1989 version. And I remember going back and looking at that as well. So it's, it's really building upon what, what past committees had done and how past committees had, had brought us forward in this understanding.
Dr. Mary Beth Hall (00:02:51):
Absolutely. I mean, the feedback and experiences that people have had since the last NRC, which informed maybe some of the direction that we could go, and with some new research that allowed us to go. It was pretty cool.
Dr. Paul Kononoff (00:03:07):
It's interesting how some fields you know, advanced dramatically since 2001, others have been somewhat stagnant. And some of that is dependent upon you know, funding. Maybe a good example is, is water. There, wasn't a lot of recent research in looking at water consumption by dairy cattle and factors affecting it. However, if you look on the protein side, you know, how, how the world is, has changed in our understanding of amino acid metabolism. There's just a tremendous amount of new research there. And so it's also dependent upon chapter as, as to the extent of revision, I guess, that that went underway,
Scott Sorrell (00:03:51):
You know, before we get started here, I'd like to officially welcome Dr. Paul Kononoff back to the Real Science Exchange. Just to give you a proper introduction, Paul, this has gotta be your fourth time here at, the exchange giving you the distinction of being one of the most frequent visitors. So thank you once again for coming here to the exchange.
Dr. Paul Kononoff (00:04:10):
Yes. Thank you, Scott. I'm delighted to be here again.
Scott Sorrell (00:04:12):
Yeah, it's awesome. Can you just kind of give us an overview, being on the committee, what was some of the most interesting things you know, during your time on the committee?
Dr. Paul Kononoff (00:04:22):
I mean, it was just a tremendous opportunity to, to be involved and to sit around in a room. So what happened is they brought us in, I can't even remember how many meetings we had, but we had several in-person meetings that were several days long. And just I mean, honestly, just the highlight of my career to sit, lock ourselves into the room with the committee that's, you know, listed at the front of the publication and discuss dairy nutrition and to talk about where it should be going and what we know. So, by far and away, the biggest highlight was just being involved in that, that team of scientists and the committee that was brought together. I'm sure I'll look back on that many times throughout the rest of my career here.
Scott Sorrell (00:05:13):
Yeah. Thank you. Mary Beth, you presented one of five webinars for the Real Science lecture series and your session was the most popular, was the most widely viewed. So congratulations for that. Can you kind of summarize for us what some of the biggest changes were for the feed intake and carbohydrate sections as compared to the 2001 edition?
Dr. Mary Beth Hall (00:05:41):
Well, let's go to the feed intake first. I mean, and so much of what we do with nutrition, like just about everything, relies on getting a handle on the animals intake. And the improvements that have been made the last NRC, I mean, besides looking at more different animal factors, including parody, we're bringing factors associated with the diet table. Including forage, digestibility, and ADF to NDF ratio that essentially lets you bring in the concept of how much grass is in the diet versus how much legume and perhaps how much non-forage fiber sources are there. And, you know, just looking at the graphs of the data now; a lot less bias, and a lot more accuracy. But I tell you what, having been in extension and worked with herds of cows who I decided had never, had chosen to never read the NRC to know what they were supposed to do. We've got some really cool improvements to investigate in the field, but people aren't going to have to pay attention to the point that there are other factors, including management environment and so forth that will influence what their cows do. And so now, I think we've got a heck of a good starting place for that. And we'll get to see where it goes.
Dr. Clay Zimmerman (00:07:15):
So Mary Beth, what specifically changed between the this, this version of the NRC and the '01 NRC in regards to the dry matter intake equations?
Dr. Mary Beth Hall (00:07:29):
There are two different dry matter intake equations that the new NRC has. And one of them is looking at the animal factors that you use as your opening volley, if, as you're trying to predict what might, what the animal response will be on a diet what's in their diet and that would include parody, milk, energy, body weight, body condition score- which hadn't been there before- and those cover the animal factors. Then, when you go to the equation that has the plant factors or the dietary factors involved, then you get into the forage NDF. Basically it's something that likely will limit intake dependent on, based on fill. The ADF to NDF ratio, Forage NDF, digestibility, milk yield, and such. I mean, so I guess the biggest changes from the previous NRC would be the number of different factors that are brought together, including a much closer look, I think, at the diet for what will influence intake.
Dr. Clay Zimmerman (00:08:42):
So certainly there there certain stages of lactation where physical fill would be more limiting?
Dr. Mary Beth Hall (00:08:50):
I mean, that pursuing now. There's no quite way to tell because I mean, stage of lactation or lactation number depends what's going on at the time, you gotta assume. If we look at parody, you got water, the animals requirements that are going to end up driving intake. I mean, for a first lactation animal, certainly she's going to be focused on getting nutrients for growth as well as milk production and eventually reproduction, and putting back reserves. But day of lactation, you have some of the same things that come into play, but milk yield or milk energy is going to weigh heavily on what that means. And so it's important to consider all of them together. The, body condition score piece that's in the animal, the animal related equation. That's kind of curious because it, it showed up. It was brought into the equation, but what does it mean? I mean, is it when an animal is on the low body condition score size and she needs to gain body weight and it isn't due to health issues or whatnot, is it animals on the other end of the scale with a lot higher body condition score that might not see the need, or feel the need to consume as much? I look forward to seeing how that plays out.
Dr. Paul Kononoff (00:10:28):
And then maybe just if I could just add a little bit on these, these equations. I thought it was really interesting, you know, okay. So now you have two equations. So when do you use those equations? And I mean, the text will, will describe that. And I know Mike Allen at the discover conference mentioned, mentioned exactly that, and he had some discussion, but maybe we could just highlight that. So the, the one animal factor, what, so often there's three dry matter intakes on ration formulation. One that, you know, the cows are doing, maybe one that you want to calculate, and then obviously the, the second one calculated with, with diet factors. But, but he suggested really this, this animal model be used as a base to predict dry matter intake, and then the second one be used, you know, when you're formulating diets and perhaps manipulating different ingredients that could be affecting, affecting the filling effects of the diet. And so that's really where those two different equations can be used by a nutritionist.
Dr. Mary Beth Hall (00:11:33):
Yeah. I mean, the animal base is the one you have, you can have with some certainty. The, the forage base, it's so malleable depending what you do with the diet, it, it should give you directionality at the very least.
Dr. Clay Zimmerman (00:11:50):
So, Paul, I know we've gotten into this in some of the other podcasts that we've done, but how does breed play into this?
Dr. Paul Kononoff (00:12:00):
Yeah, so we, yeah, we, you know, and that's, it's interesting. I know when we were at the discover conference, there was a frequent question, like, okay, how does this equation affect Jerseys? And I know that happened, you know, when we, when our committee got together in that closed room, often, we'd say, well, what about Jerseys? The equations that are developed here are primarily based on Holsteins, and there's nothing specific to Jerseys. So the question is, what about Jerseys? How do these equations work with Jerseys? I know that they did look at these equations at using smaller animals in the data set and that the equations fit pretty well related to those smaller animals suggesting, you know, you could be able to transpose this over Jerseys. There is one equation, and I know it was cited in there.
Dr. Paul Kononoff (00:13:04):
Jim Holter from the University of New Hampshire, he's published an intake equation specific to Jerseys. But that, that obviously is not used in either of these two equations here. You know I think, you know, if you look at the animal factors. You know, milk, energy drives a lot of intake, but if you look at those factors, when, when it's all I'd say broken down onto Jerseys, my expectation is that probably we'll do fairly well with, with Jerseys. But I would say that's, you know, if we talked about things that need to be investigated into the future, that's probably one element is, is maybe dialing down and thinking, well, how may Jerseys be different? And I think there's probably interest in that. But I expect the equations, you know, probably will do fairly well when we're working with Jerseys.
Dr. Mary Beth Hall (00:14:01):
One of the things that I'll be curious to see as we deal with animals with different feed efficiency. I mean, if you can get the same amount of milk at a lower dry matter intake, you've improved efficiency, and we know there's a range of efficiencies. So with the data that's out there, well, one can, I was going to say presume, but that's bad. One can guess that, that it should go through the middle of the animals that we have out there now. But as you have animals with different efficiencies, and it's not just due to them stripping product condition score, it'll be curious to see how this pans out as well
Dr. Paul Kononoff (00:14:46):
Was just going to maybe flip, flip the Jersey thing back to Clay. I mean, without maybe naming specific commercial products. But like, are you hearing different recommendations feeding recommendations for Jerseys compared to Holsteins with different commercial products that are currently available?
Dr. Clay Zimmerman (00:15:08):
We get that question a lot. So it's a good question. We're not quite sure how to answer that, to be honest, because almost all of our data is on Holsteins. So that's a really good question.
Dr. Mary Beth Hall (00:15:29):
That's actually what the committee dealt with it. And I think, in his presentation didn't Mike say something to the effect that the data was from Holsteins, the vast majority of the data's from Holsteins. And so to develop equations, you need data, so
Scott Sorrell (00:15:48):
Yeah. So during our webinar series, we had over 1700 people registered to listen to those webinars. Many of which from countries where the, the, the cattle are, are grazed. So how did you take that into account when you were developing your recommendations?
Dr. Mary Beth Hall (00:16:06):
Well I'd love for Paul to answer this.
Dr. Paul Kononoff (00:16:10):
Except he didn't write the pasture chapter.
Dr. Mary Beth Hall (00:16:14):
I think one of the comments was that this wasn't necessarily intended to be applicable to pasture. I mean, when you consider what's going on in pasture, it's, it's not just what the animal can eat. It's the availability of feed, it's the density of the canopy and the rest of it. I think they might've even said that this wasn't necessarily developed with pasture in mind.
Dr. Clay Zimmerman (00:16:39):
Yeah, that was another question that came up in a number of the discussion sessions had to do with pasture, applicability to pasture situations. It's just like the Jersey questions came out a lot.
Dr. Paul Kononoff (00:16:52):
But Mary Beth, I think you could probably weigh in on that. The, especially from the carbohydrates side and the pasture side, you know. One of the new things in this report is that, you know, we do focus on, we have a measure of starch and then, while water-soluble carbohydrates is not directly used in any of the equations, the ROM is. But when you think about pastures and the water soluble carbohydrates, and maybe it's not applicable to this report, but, but future reports, I mean, how important is that component on, on a pasture situation?
Dr. Mary Beth Hall (00:17:32):
And something like, okay, ROM residual organic matter, and it's used in the energy equations. What it is is basically the old NFC, non fiber carbohydrates by difference, minus starch. So what it encompasses are going to be the water-soluble carbohydrates, which are sugars, fructans, oligosaccharides, and so forth. It'll have the pectins in it. Any of the carbohydrates that aren't in NDF, and are not starch, will be in the residual organic matter, along with other components we don't measure and along with the error. What I was told was that the energy equation seemed to work rather well even using that. One of my questions would be- continues to be- I, I mean, our diets that we feed to cattle are still pretty starch centric if you're looking at the major NFC that goes in there. So it is part of this, this residual organic matter that has the other carbohydrates, like Paul said, are going to be important in pastures. Does it just have a lesser impact because most of the data sets we've looked at don't have quite as much in there. Again, you need data to explore this. And so we need to see from here. Your, your thoughts on that, Paul?
Dr. Paul Kononoff (00:19:09):
No, I, I agree. I mean, and certainly when it came to water soluble carbohydrate, I mean, we just, there was really was, was data where we're really limiting to really use that information. But you're right, especially in the US, obviously we're highly dependent upon starch in our diets, and a lot of studies since 2001 have been reporting starch.
Dr. Clay Zimmerman (00:19:33):
So back to the pasture question, how much would, how much would activity impact dry matter intake in these grazing situations?
Dr. Mary Beth Hall (00:19:44):
Okay. Clay, define activity.
Dr. Clay Zimmerman (00:19:45):
Well, I'm thinking walking distance in this case.
Dr. Mary Beth Hall (00:19:49):
Okay. So that's driving some of the nutrient requirements for energy, right? Okay. So I mean, isn't part of the discussion about pasture how much work you're asking the animal to do? How much milk she's making, what she needs to meet those needs, and then what's actually available on the pasture that she's offered. I mean, let alone the mud, and let alone the weather, and let alone anything else. It's how many pieces come together, and they can all be moving in different directions. If I was going to guess, and strictly a guess, I'd say activity might affect it, but the ability for the cow to meet her needs on pasture is going to depend, even with added activity is going to depend on a lot of other things. Does that feel right, Paul? And Clay? What do you think?
Dr. Paul Kononoff (00:20:49):
It's one of the things, I mean, there's just, again, you know, not a lot of data out there controlling physical activity and then the effect on feed intake or even energy metabolism for that, for that matter. But certainly, certainly it is, can be hugely impacted.
Scott Sorrell (00:21:08):
Just kind of one follow up kind of question, at least from me on that is that obviously the new NASEM is targeted toward confinement animals, high production animals. Is there another body that, that is taking a look at grazing animals and other parts of the world that we could refer our listeners to?
Dr. Mary Beth Hall (00:21:28):
Paul, would you want to bet New Zealand has done substantial amounts of work on intake on pasture?
Dr. Paul Kononoff (00:21:33):
Yeah, there's certainly investigators in not only New Zealand, but Ireland that are working aggressively in those two areas.
Dr. Mary Beth Hall (00:21:41):
And in different parts of the United States, for that matter. And especially, I think as, as you look at some of the things for what they did, what I would guess to organic dairies and to that portion of the market. But yeah, the countries that have been most reliant on pasture, it would make sense to look, to see what they've evolved and understand that our conditions. I mean, if you're, if you're going to graze bermuda grass, it might be a little different than Italian rye or perennial rye grass.
Scott Sorrell (00:22:17):
Great idea.
Dr. Clay Zimmerman (00:22:17):
Back to the water-soluble carbohydrate discussion earlier. So this is a question that comes up a lot. So a lot of the forage reports that are coming back from the labs, it'll report ethanol-soluble carbohydrates and water-soluble carbohydrates. What's the difference between the two?
Dr. Paul Kononoff (00:22:37):
Before Mary Beth answered that question, you know, I, I remember our early days, you know, the committee actually discussing exactly this and trying to figure out really, you know, what measures should we be looking at? What measures should we report in our feet tables? And obviously the expert we have here in the room today, but she helped us sort through some of these analytical differences, Mary Beth, how did you direct the committee?
Dr. Mary Beth Hall (00:23:06):
Okay, I'll take blame. Actually. It it's worked over- I'll give you an answer in a minute, but, but it was work over a number of years touching base with other scientists to say, how does this look to you? And does this look like the right direction? That, because anything we measure, it's got to meet a few criteria. It darn well better be nutritionally relevant if we're going to use it in diet formulation. It's gotta be something we can actually measure through commercial labs if we're gonna use it in diet formulation. And for myself, I feel kind of cautious about telling to people to go for more extreme analysis before we've got good justification for them, okay. And extreme, let, let's say a lot more detailed is a lot more expensive. Okay. Where we started out was with ethanol soluble carbohydrates, and that's, those that could be extracted in 80% ethanol.
Dr. Mary Beth Hall (00:24:07):
Seemed like a good idea at the time. We thought we could split out sugars, sugars versus non sugars and get a nutritional entity that would behave itself. Problem was, I hadn't looked at grasses. Grasses have fructans, and 80% ethanol extracts some of them, and doesn't extract some of them. And there was no nutritional justification for leaving the larger ones behind, and not counting them as a digestible carbohydrate. Also much to my chagrin, discovered that lactose isn't particularly soluble in 80% ethanol, and that most definitely is a sugar. And so we went through analysis, looking at comparing ethanol versus water-soluble carbohydrates. What with water-soluble carbohydrates is encompassing more, and went with the phenol sulfuric acid assay for those carbohydrates, rather than reducing sugar because it was more comparable to what a high-performance ion chromatography gave us, okay, with one caveat. When you're analyzing most of your forages and other feeds using sucrose as a standard is fine.
Dr. Mary Beth Hall (00:25:31):
When you're analyzing things with lactose, you better use the lactose as the standard, because the standard that you use in that assay method matters. Try, try to use something that's as close to what you think is in there as you can. But at any rate that's, that's the all behind. Water-soluble carbohydrates are more encompassing, and by putting the assay out there, there's hope by the time we get around to another NRC or a NASEM, if people have an assay to work with, we might have more data to be able to handle what needs to be looked at, or can be evolved.
Scott Sorrell (00:26:08):
Maybe circling back a little bit on the the feed intake. What are some practical implications that the changes that you guys have highlighted, what implications will that have on balancing dairy rations going forward?
Dr. Paul Kononoff (00:26:19):
So I, I think that the the feed factors equations, I mean, when you look at using some of these different forages- corn silage versus grasses versus alfalfa- I mean, when you're making those decisions, I think that equation will be pretty nifty and useful. Especially given, given all of the factors that, that it influences. I think though the one area, you know, and I think about implications for future research, is I think recommendations in the report are not to use that equations when you're manipulating byproducts, because the, the physical nature of those feeds is just so much different. So, I think when looking at forages, that second equation will be extremely useful. And in the future, hopefully we can do more research on the by-product side of things and better understand the fiber and byproducts. So that would be maybe my take on it.
Dr. Mary Beth Hall (00:27:22):
So, so actually, Paul, I mean, some thing you just said about, yeah, the byproducts, which are anything but uniform, it, it sort of looks like figuring out how best to handle those. And maybe residual organic matter are our two gaps that we've got that we need to fill. Yeah?
Dr. Paul Kononoff (00:27:43):
Yeah. Yeah, I'd agree.
Scott Sorrell (00:27:45):
One thing I did want to know was if you guys, did you get involved in looking at dry matter intake for dairy cows or the dry cows calves or heifers, or was that left to those, those a chapter authors?
Dr. Paul Kononoff (00:27:57):
So the heifer, there is a heifer equation and a dry matter intake equation. And then for dry cows, there's, in the dry cow and transition chapter. And then of course, calves as well, there's an intake in the calves chapter. So, so that is separate from the dry matter intake chapter. Yeah. I'm glad, glad you asked that question.
Dr. Clay Zimmerman (00:28:20):
So the dry matter intake chapter's really just applicable to lactating cows?
Dr. Paul Kononoff (00:28:24):
And growing heifers. I believe there's an equation for that for heifers.
Dr. Clay Zimmerman (00:28:30):
Which feed factors specifically are in, in that dry matter intake equation that's related to, to the diet factors?
Dr. Mary Beth Hall (00:28:39):
For what the specific feed factors that you have there. And this goes into, this goes into the second equation, not the main animal factors that you want to look at. It's the amount of forage NDF. And that goes to the point of how much fill are you bringing into the diet. And you got to understand, there are probably some assumptions there about how coarsely or finely chopped that material is. If it's really finely chopped, I don't know how that that'll fit ADF divided by NDF, which as mentioned earlier, gets into the ratios of the two between grasses and legumes. And how they'd affect intake. Forage NDF digestibility, which the more digestible a forage is, the less filling it will be. The less digestible it is, the more filling it'll be, and have greater impact on intake. Let's see...and that as far as I can see as it for the specific forage factors.
Dr. Clay Zimmerman (00:29:55):
So which time points did you use for NDF digestibility?
Dr. Mary Beth Hall (00:30:00):
I'm pretty sure it's the 48 hour. But that's something I'd have to go back and check. Do you have a different recollection, Paul?
Dr. Paul Kononoff (00:30:08):
Well, the 48 hour is what's listed in the feed composition tables, but I know the paper that was used to develop this- Alan Souza and Vandahaar- they actually evaluated I think multiple digestibilities in their study.
Scott Sorrell (00:30:31):
Clay, you want to transition to the carbohydrates section now? Yeah. So what were some of the biggest changes in the carbohydrate chapter as compared to the 2001 version?
Dr. Mary Beth Hall (00:30:40):
Okay, and mind you, the carbohydrate chapter, you don't see any equations there that go to energy or microbial protein production or anything along those lines, which is similar to what was done previously, the last NRC had the same, had the same approach. I mean, the biggest thing, I think is talking about more different types of carbohydrates in a bit more detail, getting a bit better understanding or discussion on starch of which there's a fair amount of detail, and also revisiting the whole effect of fiber question. Because we, you know, I tell people you know, the effect of fiber are often in the past. Well, yeah, I'll say this. It's been sort of like the Meese Commission- you know it when you see it. Because the physically effective fiber works as wonderful as it has been in giving us insights as to how particle size, how NDF affects rumen function.
Dr. Mary Beth Hall (00:31:49):
It felt to me like it had a largely research focus. And, you know, so the last NRC they had, I think table 4-3 that had forage NDF, total NDF from the diet, maybe ADF and NFC to give you an idea of what direction they should go as you're feeding more or less of one or another. Ended up revising that for this publication, but bringing starch into the equation as opposed to NFC. And then also an entirely different approach that more specifically looked at different dietary factors, which is the physically effective fiber approach, which I will gladly hand off to Paul
Dr. Paul Kononoff (00:32:38):
Yeah, so as, as Mary Beth mentioned, the previous NRC had this table, or 4-3, and we spent a lot of time talking about that. And I think time has shown that that table has been extremely useful and very applicable to many diets situations. And then one of the things that has has happened since that last NRC is that there has, as Mary Beth mentioned, been a lot of work on forage particle size as specific to the Penn State particle separator. So quick plug out to Penn State, even though they lost to Iowa, but that device has been extremely useful. You look at the industry and how they've used it. I mean, I think, it's safe to say most dairy nutritionists drive around with it in the back of their pickup truck, or it's sitting in their garage, or in their back to their car.
Dr. Mary Beth Hall (00:33:39):
And they use it!
Dr. Paul Kononoff (00:33:41):
And they use it! In fact, I think if you Google dairy nutritionist, you'll probably see a nutritionist shaking the Penn State particle separator, not sitting down doing ration formulation. But you know, that that device is used a lot everywhere around the world. And so I think the committee, well taking a step back, several coauthors and myself, Robin White, Jeff Berkins, Mary Beth, we said, you know, how can this device be used to formulate recommendations for effective fiber?
Dr. Mary Beth Hall (00:34:15):
But, but, but wait a second, wait a second. When we first started discussing this, one of the deals was we weren't sure we were even going to find anything, that it was relevant or not. But, but you look because this was one tool for looking at particle size that people actually used in the field. And that's, that's where the recommendations were needed. Go for it.
Dr. Paul Kononoff (00:34:40):
And so separate from, I guess, the committee responsibilities, you know, really what we did is we said, okay, can we, can we find the scientific papers that have looked at forage particle size, as well as other nutrient analyses that are commonly used? And then what have these, what have these studies looked at in terms of animal measures? And you know, our, our group that, that worked on these papers really hung our hat on two different components. But the whole idea is that effective fiber is related to rumen pH. And so we saw that as an important element to investigate. And I think as many of your viewers know, the whole notion of effective fiber is related to not only rumen pH, but the impact of rumination and what that has on saliva production and rumen buffering. But in general, just rumen conditions.
Dr. Paul Kononoff (00:35:47):
We know that as cows ruminate, saliva production happens, there's rumen motility. Good things happens for the cow, happens to the cow. Long story short, you know, this kind of working group designed a number of equations to evaluate this whole notion of effective fiber and rumen conditions, and attempted to use these equations to predict particle sizes that are necessary for optimal rumen conditions. And so the committee did adapt some of the equations and use the equations for a few tables that are listed in the publication that show some examples of really why particle size matters and why particle size influences effective fibers. So getting back to the old NRC 2001, although chemical composition was very useful, what we were able to do is take out that yes, not only chemical composition, but the physical components of the diets also affect effective fiber and rumen conditions. And so I think that was an important step. Is that applicable in all situations? Probably not, but just being able to tie these measures to this device that dairy nutritionists use kind of around the world, I think is, is an important thing to identify and to be sure is included in the discussion of effective fiber.
Dr. Clay Zimmerman (00:37:16):
The term that, that you used in the, in the publication is physically adjusted NDF, is that correct? So which screens are important on the Penn State particle separator, or which, which screens really drive that ?
Dr. Paul Kononoff (00:37:32):
I think most of the year listeners will know, and I'll keep it in metric. That's the scientific unit of measure. But the, the first screen is 19 millimeters. The next screen is 8 millimeters. And then there's two other screens that are commonly used, one measuring 1.18 millimeters or 4 millimeters. So which one matters? And I think it, it probably depends on what you're thinking. First of all, yeah, as Mary Beth said, they're, they probably all matter because what you're really interested in is the particle size distribution. But you know, if we have to think, well, we, we also in, in when we were working on those papers, ask that question, we know, you know, loosely that sorting activity is highly related to particles on that top screen. Those are large particles that the cows are able to sort. What probably is able to change the most on most management situations or harvesting conditions is actually that, that second screen. Number one, that that is a high proportion of the feed that's found there, and that's, what's manipulated most often. And so in this approach of physically effective fiber, what the users are actually doing is looking for an optimal range that's found on that second screen. And then the third screen, 1.18 millimeters or 4 millimeters, that's obviously heavily driven by, by the grain component of the diet.
Dr. Mary Beth Hall (00:39:15):
One of the things that was pretty neat here, I think, and is, is also a heads up to the folks who would use the app that goes along with this, which is called- for the physically effective NDF, there is an app- free- that's called Munch for dairy cows. I'd like folks to remember with this is that we say there's a target ruminal pH for this app that kind of proxies in what is a healthy rumen, but it's a proxy. It's not, there are a lot of things that affect ruminal pH, but so we're aiming for it as a proxy. The other part is that you do need to get the dry matter of what's on the different screens, because as we went through looking at this every which way, from Tuesday possibly Wednesday, sometimes Saturday, I mean, well, what we were ended up finding is that there was too much variability in what we were seeing in the water content, and that would just foul the ability to look at what was on the different screens, and relate them to something. And so to do that, it's just knowing what's on the different screens, taking a portion and whether with an appropriate microwave and scale, or a costs or test or something along those lines, get a dry matter on it. And then you'll have numbers you can use.
Dr. Clay Zimmerman (00:40:50):
So the dry matter off, off the top two screens, or?
Dr. Mary Beth Hall (00:40:56):
That will be off of whatever. If you look at the app, it's asking for the proportion of the TMR dry matter that's on the top two screens. Yes, Paul?
Dr. Paul Kononoff (00:41:08):
Yes.
Dr. Clay Zimmerman (00:41:09):
Okay. Okay. Just don't use the microwave that's in the kitchen if you can help it.
Dr. Mary Beth Hall (00:41:14):
We take no responsibility for others' actions in selection of microwaves to use.
Dr. Clay Zimmerman (00:41:25):
Switching gears just a bit- go ahead, Clay. I was going to ask about, about starch degradability, and how the committee took that into account in grain processing and so forth.
Dr. Mary Beth Hall (00:41:40):
Of course, with the PANDF system, or in general?
Dr. Clay Zimmerman (00:41:45):
In general.
Dr. Mary Beth Hall (00:41:46):
Okay. We know it matters. Okay. I'm allowed to leave a lot of silence for like several minutes after that. I mean, part of the challenge you've got with- okay. Part of the challenge you've got with anything is being able to measure it, and know what it relates to and having consistent measurements. Yes? If you can't measure it, you can't manage it. I mean, I think relatively speaking, we've got fiber digestibility in pretty good hands for numbers being interpretable. I mean, there's been discussion about how we should approach starch digestibility. And again, we know it matters. But I do not recall whether it was from lack of data or variability in methods used that, that some of this didn't get into some of the other equations. And Paul, do you have recollection for..?
Dr. Paul Kononoff (00:42:59):
I, I would probably say both there is an adjustment for, you know, the form of corn that's fed and that is, but it's, it's a pretty simple estimate that's changed by the, like the forearm dry roll versus high moisture corn, and that kind of thing. But, but we are not using invitro starch digestibility in, in any of the models.
Dr. Mary Beth Hall (00:43:26):
Okay. So actually, Paul, going back, the I mean, starch degradability did show up for predicting microbial protein yield, right? Or, I mean, even in round terms. Okay, you know, again it's trying to get folks to work on methods evaluation, even. I mean, I mentioned earlier that something needs to be nutritionally relevant and measurable and so forth. And we faced the same thing, we faced the same thing here. My impression is that, you know, we have various indices that are really pretty helpful for our, rhe in vitro measures. But I'm not sure.
Dr. Mary Beth Hall (00:44:18):
I, I, I'm not sure I've seen... And okay, the next question you should ask me is Maribeth have you actually looked? It is looking at the question of how consistent are, let's say starch digestibility measures done in different laboratories and so forth and so on. Different sources of inoculum and rest. And some of this, just, if it hasn't been vetted already, it needs to be. And then recommendations made for how people should try to measure. That's, quite honestly, telling people how to measure something is the best way to find out what's wrong with the assay. I tell you from experience.
Dr. Clay Zimmerman (00:45:06):
So do you, do you address starch, starch assays and the feed analysis chapter?
Dr. Mary Beth Hall (00:45:12):
We do. We give a recommendation for starch analysis, not for a starch degradability analysis. Okay.
Scott Sorrell (00:45:20):
You know, before we leave the carbohydrates, a client was curious, you know. As you guys, part of the process is obviously you do a literature search and you're you dig into the data, you see what it's, what's new. What were some of the biggest gaps that, that you found that you wish you had? And then, you know, looking forward as you leave cookies for your predecessors that are gonna go on to address this down the road, what are some of the things that that you're going to tell them that they need to address the next time?
Dr. Mary Beth Hall (00:45:50):
Oh, Paul, would you touch on that as, as an, as an innocent bystander?
Dr. Paul Kononoff (00:45:55):
Okay. Yeah. Mary Beth is asking me to go first- talk about a loaded question. You know, of course it's, and I don't know if we're going to officially talk about it today. It's something that's near and dear to my heart, but it doesn't get a lot of airplay compared to the coefficients of digestion or the amino acid concentration. It's just simple chemical analysis. And you know, we spent a lot of time on our, on our chapter that describes chemical composition of feeds. But I would say that's one thing, you know, if we look at papers that are being published in the journal of dairy science, and you go to do a meta analysis or to, to gleam things out of those papers, I would say that's one thing we're getting better, but it's one thing that we're just not seeing as a complete description of of all of the feeds, but even the forages themselves.
Dr. Paul Kononoff (00:46:55):
I know like me personally, I remember when I was at Penn State doing my PhD, Dr. Varga, I remember her specifically saying, well, if you want to help the next committee, think about the inputs that are used in this model and use these inputs and report these inputs in your papers that are published in the Journal of Dairy Science. But, you know, surprisingly there is some limitations on, on many of the, the, the forages and the chemical description of the forages. So I think that's the big one is actually describing the feeds using the methods. I think I hope, and I expect that this publication will provide additional guidelines around the methods that are used to decide these feeds. But, but just the complete description of the feeds, not only chemical composition, but as we already mentioned, particle size of the diets as well. So I guess I would say that would be a big thing in the future that I would like to see us doing more of is describing the feeds, so. Mary Beth, are you willing to take a run at that question
Dr. Mary Beth Hall (00:48:01):
Seeing as you were so kind to take first stab, I'd better. I thoroughly agree with Paul. I mean, if you don't have the information that describes the picture, you have so many large gaps that the, these blank spots. That it makes it harder for you to take a variety of studies and piece them together and see what story they have to tell. You know, you mentioned starch digestibility was something that's over 20% of the diet frequently. It'd be really, really, really good to have a better handle on how that behaves within the animal. One of the reasons that, but one of the sets of commentary within the carbohydrate chapter, is not wanting to deal with KD and KP, rate of digestibility and rate of passage, because we don't have ways to get, especially, the rate of passage inputs.
Dr. Mary Beth Hall (00:49:03):
And if you think about rate of passage, that is a harvest mechanism for the rumen. It's what gets to the small intestine, and it decides what's going to be held in the rumen to be converted by the microbes, to the extent they can. And so much hinges on that. Because I did something bad in a previous life, but then looking at liquid passage kinetics. At the last ADSA meeting, I presented information that said, all right, it's actually a two pool, three kinetic grade system. Because you've got things that are in the liquid fraction with the liquid, and with the solids. And you have material passing out with the liquid with the solid, and passing from the solid to the liquid. And some of this is based on work that one of Jeff Perkins students did. We could use more information on kinetics, and we could use more information descriptive of diets and, and whatever pieces you can bring together in a study to try and make them more complete. Just, just understand that when some large blind spots are left, it leaves us going blind. We, we, we can't move forward with it.
Dr. Paul Kononoff (00:50:24):
Yeah. And so I, as, as Mary Beth was talking, I was listening, but just, you know, flipping through some of my notes, you know. As, as dairy nutritionists, many of us are interested in the lactating cow. And I think it's, it's fair to say that there has not been a lot of research on growing heifers. And I think the committee, that was one of their challenges is, is finding data to outline new and updated nutrient requirements of, of growing heifers. Not my area. But I, I do know that that's probably an area that we need more work on in the future.
Dr. Mary Beth Hall (00:51:02):
Okay. One of the things you will note is that Paul and I may very gladly suggest things for other people to do.
Dr. Paul Kononoff (00:51:16):
Especially passage.
Dr. Mary Beth Hall (00:51:17):
Yeah. Especially passage. Yeah. Nature of the beast.
Scott Sorrell (00:51:23):
Yeah. Paul, you were talking a little bit about some of the gaps specific to feed composition. Let's talk a little bit about what people that they'll be buying the new NASEM, they're going to get it mid December, what kind of revelations specific to feed analysis and composition will they find?
Dr. Paul Kononoff (00:51:42):
So that was, I think the committee, you know, we, we had a lot of fun working on feed composition, believe it or not. And we saw there huge opportunities to develop better and to publish better information on feed composition. One of our big partners was the USDA and NAMP program, which is a program designed around feed composition. And we had several post-docs helping us in working in that area. But we're, I think we're all particularly proud of this new feed library. Is there anything, you know that will make a lot of eyebrows raise? Perhaps not, but one of the things I think most importantly, what we did is we had a number of key feed labs here in the United States that graciously supplied us data. And then we were able to employ over that data, actually, a procedure that had been published by Peter Yoder and Bill Weiss from Ohio State, and use that to basically clean up the data set that we were supplied from these commercial labs.
Dr. Paul Kononoff (00:53:01):
So, a good example was corn gluten feed. What we were able to do is actually-. listeners are probably not surprised to hear that people mislabel corn gluten feed with corn gluten meal all the time. In fact, they may not even label it, they'll just call it corn gluten. And so that's, that's a feed that, you know, is a good example of, we don't really know the chemical composition of it, especially if you go to these feed libraries, because there's just so many feeds that are misclassified. And so we were able to use this approach to actually clean up the data sets. We have a large data set, and we were able to clean it up and get good estimates of the mean, but perhaps even more importantly, get good understandings of the type of variation you have within analyte and within feed.
Dr. Paul Kononoff (00:53:56):
And so in addition to reporting the main standard deviation, and we're also going to be reporting the 10th and the 90th percentile of each analyte that's listed there. And I think that'll be extremely useful for people in the field to understand, not only the main chemical composition, but what kind of variation can be, is involved with them each bead stuff. And so developing the feed library again, maybe wasn't the most exciting thing we think it's particularly important. Working with even just standardizing the feed names as well, but we thought that was important. So I'm actually kind of excited to see, you know, how people are going to be able to use the feed library and what improvements that has on predicting animal performance.
Dr. Clay Zimmerman (00:54:46):
So are there are there some new nutrients or analyses that are in the feed composition tables now that weren't in the '01?
Dr. Paul Kononoff (00:54:58):
That's a good question. I think probably the best answer for that is not really. Mary Beth, you can correct me if I'm wrong. But basically typical chemical analysis that you would get from the feed testing lab, if you look at the, the protein fractions and digestability fractions, there's the A, B, and C, as well as the rate of of digestion in the rumen. Rumen undegradable protein, or RUP, and then the digestibility of the RUP. I think the what's what's been improved there, just like particle size, here's been more studies that have actually reported, tested and reported the intestinal digestibility of the RUP. And so I think we've made advancements not necessarily in the analyte that's reported, but some of the understanding and the estimates around the digestibility of, of bypass protein. The I guess, yeah, that's probably the main one. I think the previous one did report-oh, go ahead, Mary Beth.
Dr. Mary Beth Hall (00:56:05):
Oh, I was going to ask you, do you remember what analytes went into the tables of composition that weren't used elsewhere in the document? I mean, I'm thinking soluble protein was there and I don't think that's elsewhere. Did water-soluble carbohydrates make it in or no?
Dr. Paul Kononoff (00:56:28):
Yeah. So, yeah, so that's, that's the thing is early on, you know, unlike probably previous committees, we started working on the feed composition library early on. So we weren't absolutely sure what analyte would actually be used in the final model, but we had a pretty good idea. And so Mary Beth mentioned there was, there was two analytes that we weren't exactly sure if they would be used. Those would be water-soluble carbohydrates and soluble protein. To my understanding those two analytes are, are reported, but they're not used in any model. They can be used to evaluate feeds, perhaps gain understanding of the feeds, but, but those nutrients aren't used in any of the reports. Oh, the other thing is you know, very generously, Cornell provided a fatty acid data for us. And we also had a commercial lab that provided us some individual fatty acid data. So, so those are new analytes to, to this publication. They weren't in the previous one.
Dr. Clay Zimmerman (00:57:40):
So you, you talked about residual organic matter earlier. Is that included in the feed composition tables?
Dr. Paul Kononoff (00:57:49):
Mary Beth, you want to answer that?
Dr. Mary Beth Hall (00:57:52):
I dont think so.
Dr. Paul Kononoff (00:57:53):
And so it's not in there, but it's calculated in the model.
Scott Sorrell (00:57:58):
Paul, got a real quick question, or Mary Beth. The-. So we know that our forages have been genetically enhanced over over the years. Has there been any drift in nutrient composition from that? And so, did you see any big differences between 2001 and 2021 in terms of what the nutrient values looked like for specific feedstuffs? What were some of the biggest differences you saw?
Dr. Mary Beth Hall (00:58:25):
One of the things that really aggravated Peter Vansuus was when he looked at a table of nutrient composition and it had mature alfalfa, immature alfalfa, ya dee da. And it didn't show any particular difference in composition. And and what it went to was something that Paul just talked about, where there were feeds that were mislabeled, misrepresented for what they were. And it's sort of like one of the past NRC's when there was a really, really high fiber content on, might've been one of the corn glutens, but it's because they didn't add amylase and get the starch out of that particular feed stuff. So, you know, you asked about how this is going to compare with past ones. At the very least, you might have greater certainty that what you're looking at our numbers for what you intended to look at. What else have you seen, Paul?
Dr. Paul Kononoff (00:59:37):
Yeah, actually nothing really comes to mind as far as glaring differences. I know there's probably some good examples of just wrong, wrong numbers in past publications, but nothing, nothing particular is coming to mind. I think Mary Beth is right. I think, you know, I think we're just getting a more accurate reflection of the chemical composition.
Scott Sorrell (00:59:58):
So then with that, I'm going to call last call and ask each of you to kind of give us one or two, maybe three takeaway messages for the audience today, from our conversation. Paul, let's start with you.
Dr. Paul Kononoff (01:00:14):
Yeah, I guess I guess what I would just note is certainly in the last 20 years, one of the things we know, we've, we've noticed and discovered is that particle size of forages do matter and that Penn State particle separator can be a good device to use to understand how those, how those differences in particle size can affect rumen conditions. So I think that's probably the biggest take home message, I think about when I think about the carbohydrate chapter.
Dr. Mary Beth Hall (01:00:48):
And actually for the record, despite the fact that Paul graduated from Penn State, he has colleagues who very much agree with him who did not go to Penn State that is his statement is accurate.
Scott Sorrell (01:01:08):
Yeah. And Clay I must apologize. I did not ask you what you're drinking the evening, but I did notice that it looked like you were enjoying another cider again. Is that the, the, the old standby?
Dr. Clay Zimmerman (01:01:19):
I am. This is a cranberry hop cider . Yeah, Kansas.
Scott Sorrell (01:01:26):
Very nice. And I know exactly from whom you got that, the same person I got my, yeah. So I've got a bourbon tonight that I'm enjoying as well called a Wabash Reserve, comes from the great state of Kansas. And that was given to me by a friend Stacy Mayo Martinez, and Stacy, why don't you just jump on here real quick, if you don't mind. Stacy is the brains behind the operation here. She keeps these things working. And if you need to, if you want to have your own podcast, I would recommend Stacy in a heartbeat. So thank you very much for the bourbon. I'm enjoying it. It's awesome.
Stacy Mayo Martinez (01:02:03):
Glad I could send a taste of Kansas out to you all.
Dr. Paul Kononoff (01:02:07):
You're even wearing purple today, I'm impressed.
Scott Sorrell (01:02:12):
So Clay what kind of final thoughts do you have for us?
Dr. Clay Zimmerman (01:02:16):
Well, I think, I think a couple of things I would echo what Paul said. I think linking this back to a tool we actually have in the field, the Penn State particle separator is, is great. There are a couple of tables that I believe will be in the publication that Paul and Mary Beth were referring to that I think will be very helpful with the thought process there, with, with carbohydrates in the diet. And you know, and, and as, as far as the feed intake predictions, I mean, obviously if we know dry matter intake, we work off of known dry matter intakes, but you know, occasionally we get into situations where we really don't know dry matter intake. So anytime we can improve these prediction equations, that's certainly helpful to us in the field.
Scott Sorrell (01:03:05):
Thank you, Clay. And Mary Beth, I'll give you the final word
Dr. Mary Beth Hall (01:03:08):
First. This has been a pleasure. My final word, because Paul's already taken over the one that went with the Penn State particle separator, I'll speak to the methods. If you're going to try to get inputs for the new NASEM, make sure you use the methods that are listed, or some variance that's allowed in the citations that go along with those methods. It's to ensure that everybody's on the same page and you're getting the numbers you need, that the model would be looking for to be able to give you some answers back. And quite honestly, you know, back to something Paul said earlier, if we're all using the same methods to get some descriptions of our feeds and what we're working with in research and in the field, we're in a better position to move further ahead yet.
Scott Sorrell (01:04:05):
Well, thank you for that. And I want to thank all three of you for an enjoyable conversation this evening. It's, it's, it did not disappoint and also want to thank you for the the dedication and time and effort that you guys have been that you've put into this new NASEM document it's it's much appreciated. So on behalf of Balchem and the industry, I want to thank you. Also want to thank our loyal listeners for stopping by once again, here at the exchange. We hope you continue to find value and practical tips that impact your business. As a reminder, we will continue breaking down the new 2021 8th revised edition of the Nutrient Requirements of Animals over the coming weeks. Be sure to subscribe, so you don't miss any of the new episodes. If you'd prefer to pre-order a copy of the new NASEM and receive a 25% discount visit balchem.com/RealScience and click on the NRC Series for a link and the discount code.
Scott Sorrell (01:05:02):
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