Guests: Dr. Jim Drackley, University of Illinois; Dr. Bill Weiss, The Ohio State University; Dr. Mike VandeHaar, Michigan State University Tonight, we continue our discussions with the authors of each chapter of the new NASEM, formerly the dairy NRC. We’re focusing on dry cows, calves and heifers for our conversation and it should be a lively one. Here is a link to the webinar on the new report: https://bit.ly/3B5z2MZ.
Guests:
Dr. Jim Drackley, University of Illinois
Dr. Bill Weiss, The Ohio State University
Dr. Mike VandeHaar, Michigan State University
Tonight, we continue our discussions with the authors of each chapter of the new NASEM, formerly the dairy NRC. We’re focusing on dry cows, calves and heifers for our conversation and it should be a lively one. Here is a link to the webinar on the new report: https://bit.ly/3B5z2MZ. Also, we've got a new co-host tonight with Dr. Jeff Elliott joining us.
Dr. Bill Weiss discusses changes in the chapter regarding dry cows and transition cows. The biggest update was the changes in intake prediction, which changes every day substantially as the cow gets close to calving, making intake prediction difficult to model. There is also up-to-date discussion on all the metabolic problems within the text that doesn’t all show up in the software but is great for users to have as a reference. (7:08)
Dr. Jim Drackley discusses steam-up rations and high energy density diets. He explains there are large steps from the dry cow to the close-up cow but not a large step to the fresh cow. That is part of the problem and why they took a more moderate steam-up approach. The other problem is that cows are becoming catabolic the last few days before calving. So adjustments are made to focus on metabolism and divert nutrients to the mammary gland. (12.05)
Dr. Mike VanderHaar discussed a big change in the composition of gain. They used data from Holstein cattle instead of growing beef cattle. By doing this the intake equations are better than the last model. They also include feed factors and are size scaled. (41:44)
Dr. Jim Drackley discusses updates to the calf chapter. The requirements on the conversion of nutrients into gain are much improved because of better data based on Holstein and Jersey calf studies. (58:14)
As a reminder, we will continue breaking down the new 2021 8th Revised Edition of the Nutrient Requirements of Animals in podcasts releasing over the coming weeks. 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 with the authors of each chapter of the new NASEM, formerly known as the Dairy NRC. We're focusing on dry cows, transition cows, calves, and heifers for our conversation tonight, and it should be a lively one. Hi, I'm Scott Sorrell. One of your hosts here at the Real Science Exchange. Tonight, we're welcoming Doctors Jim Drackley, Bill Weiss, and Mike Vandehaar. Each were highly involved in one or more of the aforementioned chapters. Gentlemen, welcome to the exchange. Bill, you've been here at the Exchange a few times now. Now the last time as I remember you were drinking a local brew from just across river. So what's in your glass tonight?
Dr. Bill Weiss (00:00:59):
I stayed on this side of the river this time. I've got a 50 west American lager, it's made here in Cincinnati. Just in downtown Cincinnati, about two miles from my house. Very tasty.
Scott Sorrell (00:01:11):
Awesome. As I said before, I'm going to have to come down and have one of those with you sometime. Mike, this is your second visit to the exchange. And Jim, this is your first. So what are your beverages of choice tonight?
Dr. Jim Drackley (00:01:22):
I have a nice white wine, a Sancerre from France. That's very nice.
Scott Sorrell (00:01:30):
Very nice.
Dr. Mike Vandehaar (00:01:31):
And I have, I really like Michigan beers. Normally in the afternoon I would be drinking beer, but because you guys asked what I would like I said, some Glenlivet 15. And I'll just make sure that I drink a lot of water with it.
Scott Sorrell (00:01:50):
Very well. Well, speaking of scotch, that reminds me of the new co-host that I have in the, in the chair tonight. We shared some scotch at the World Dairy Expo together. Co-host tonight is Dr. Jeff Elliott. Jeff is a technical specialist here at Balchem. Jeff, welcome to the Real Science Exchange. And most importantly, what's in your glass tonight?
Dr. Jeff Elliott (00:02:13):
Well, in my glass as most of you are aware, and even when I was in grad school with Dr. Drakely, I was a big bourbon drinker. Drank bourbon all the time, drank it for years. Then I felt like I'd went through them all, and then been trying a lot of scotch. But my summer drink is actually tequila, and this is a Casa Amigos tequila. And I think I got introduced to this maybe the first time I met Bill. We were at a conference together in Florida and- or not Florida, in Mexico. And one of my friends introduced me to this and it is really smooth. Everybody thinks, oh, tequila. But now this is, this is not your college tequila. This, it's goods stuff.
Scott Sorrell (00:02:57):
So I consume all my tequila mixed into a margarita, but, but I understand you, you drink that straight. Neat.
Dr. Jeff Elliott (00:03:04):
I have it neat, but like Mike said, I've got ice in mine to stay hydrated, so,
Scott Sorrell (00:03:11):
Excellent. Speaking of Jim, do you have any good stories from when you worked with him down there?
Dr. Jim Drackley (00:03:17):
I think I've got several, but we have, we have a mutual destruction pack, so I'm afraid I can't share some of the best ones. But I remember one time when, when he and his wife Carina were babysitting my, my young boys that one of my boys turned the water sprinkle, or water hose on, on Jeff's son. And that was, that was a bit of a kerfuffle for a little bit, but there's lots of good babysitting stories.
Dr. Jeff Elliott (00:03:47):
Yeah. There, there were a lot. So one question, I want you to remind me if this was true. Did you tell me once that you were allergic to cows?
Dr. Jim Drackley (00:03:59):
I did, yeah. I am.
Dr. Jeff Elliott (00:04:01):
I just find that intriguing, yeah.
Dr. Jim Drackley (00:04:05):
If I would go out and work with cows and, you know, and have like contact with my arms on the hair or something, I would, I would get a rash, an allergic rash. And, and certainly being around them in a dusty situation, I would have some, some allergic reactions. Yeah.
Dr. Jeff Elliott (00:04:22):
Yeah. See, I just thought that was your excuse to get us to do the work.
Dr. Jim Drackley (00:04:27):
Well, it has some side benefits on the right the right cases, but...
Scott Sorrell (00:04:33):
Okay, great stories. Hey, before we jump into our topics, let's hear from each of you, which chapters did you work on? And then how did you become involved with the committee. And Bill, let's start with you since you're the chairman.
Dr. Bill Weiss (00:04:47):
Well we all had something to do probably with every chapter. I mean, some, some people obviously are experts in subject areas and they, they led. So I contributed to the transition, not much to the heifer, cause I don't know a thing about heifers other than they become cows eventually. And a little bit on calves, and then plus some nutrient things. And this committee, the way NRC works is, you know, they, they call people in, they need experts. And I was on the last one. So they actually asked me for names of people that I thought would be good committee members. And then at the end of that discussion, they asked me if I'd be willing to do it again. And I said one time, but no more. The next time it's somebody else's problem, so.
Scott Sorrell (00:05:31):
Yeah, very well. Jim, how about you?
Dr. Jim Drackley (00:05:35):
Yeah, I worked primarily on the calf chapter, and with input on several of the others, including the dry cow and transition and the, the fat chapter. Very little in the heifers. And I was, I was asked to join the committee by, by those powers that be, I guess.
Scott Sorrell (00:05:59):
Would that powers that be be Bill?
Dr. Jim Drackley (00:06:02):
Yeah, I think Bill and Rich, yeah, reached out to me. Yeah. Yeah.
Scott Sorrell (00:06:06):
Mike, how about you?
Dr. Mike Vandehaar (00:06:09):
Yes, also the powers that be asked me. And I worked mostly on the heifer chapter and the energy chapter. Also intake chapter with Mike Allen. You know, I think I, for years I had done some work with heifers. I had a lot of interest in the energy chapter. I've talked about energy for years, and been part of a grant on feed efficiency. And had worked with figuring out the last NRC in regards to a computer program that we had 20 years ago called Spartan. But anyway, I will say it was, it's been a lot of fun. It's been a lot of work, but it's been a lot of fun.
Scott Sorrell (00:06:54):
Yeah. Thank you. Let's start off with a dry cows and transition cows. Bill, what are some of the key changes to that chapter and what implications will that have on how we feed transition cows going forward?
Dr. Bill Weiss (00:07:08):
Okay, well of that chapter, the dry cow part is easy. It's just straight requirements, nothing special, just meet requirements. But as cows get close to calving, then requirement models really don't work well, I'm just gonna say, cause we don't know everything that these-. These nutrients do more than just act as nutrients. So there's still a lot, you know, we, we come up with requirements, but there's a lot in the text saying, you know, users should think about this and users should think about that. Updates, probably biggest update was changes in intake prediction, which again, for that animal, it changes every single day, substantially as it gets close to calving, which is difficult to model. So that'd be the biggest one. And then there's a really, I think a good up-to-date discussion on all the metabolic problems review. So there's a lot in the texts that doesn't show up in the software and it's, it's, like I said, there's a lot in there that would help. Be a good textbook, and be a good reference for a lot of people.
Dr. Jim Drackley (00:08:15):
I think one of the biggest changes that's happened was a result of the the change in the way the energy requirements or energy content of the diets was calculated. And so the, the diets are gonna look a lot higher in energy than maybe people that, that work a lot with dry cows and transition cows, are used to. So I think that's going to be a big thing to get used to.
Dr. Bill Weiss (00:08:40):
Yeah. And, and that's a good point. People, you know, but the requirements also changed. So it's.. a lot of that canceled out too. You just got to get used to new numbers that the energy balance probably are going to look pretty similar, but the numbers are going to be a lot different, they got to get used to 'em. , We think they're obviously more accurate now than the last time, but they are going to be very different.
Dr. Jeff Elliott (00:09:00):
Yeah. So can, can you explain that to me, Jim? I heard you say that. And, and Bill, you just said that, that the requirements also increase, but as I'm thinking about the, the cows they didn't change their requirement, per se. So just help me understand how that fits in.
Dr. Bill Weiss (00:09:23):
Actually, I think say I think Mike would be the best one to discuss that one.
Dr. Mike Vandehaar (00:09:26):
Yeah. I would just say that we would say that the cows did change over the last 50 years and we've been breeding for cows that produce more milk and are more metabolically active, and they have higher maintenance requirements than they did 50 years ago. Probably even 30, 20 years ago, so.
Dr. Bill Weiss (00:09:49):
But how about the supply side?
Dr. Mike Vandehaar (00:09:52):
And on the supply side, what we did is instead of using a cow fed at maintenance as our baseline, we used a cow fed at, eating at three and a half percent of her body weight as our baseline to predict the energy available from a diet. Of course, that in itself doesn't make a difference. But, but when we, we, we came up with projections for digestability on different feeds for cows at three and a half percent of body weight. And now for a dry cow, because she's eating less, the energy content of her diet, same diet, will look higher than it does for a lactating cow. You know, in the end, when we, when we made the equations, we weren't exactly sure what would happen to the dry cow. Whether the, whether the energy supply would look higher than not, and, and in the end it did, but I think it's okay.
Dr. Bill Weiss (00:10:56):
Thank, you know, the old NRC and well, even the one before this, their base was a dry cow fed at maintenance. Which is about, for some of these is about six kilos. You know, 12 pounds, 14. So extraordinarily low intakes. Impractical intakes, but that was really the base. So, and that I think caused some problems.
Dr. Jeff Elliott (00:11:19):
Another question I have along the dry cows. So in the beginning of my career, you know, I left Jim's lab in 1995 and went out into the industry, did a lot of ration work. And that's when the steam-up rations really started becoming popular. We used them for many years and despite the lack of data to support them now, at the time they were the best knowledge that we had, and philosophically, actually seemed directionally correct. So I guess my question is with those steam up rations then and what we know now, how did those, how did that philosophy maybe help or hurt us?
Dr. Jim Drackley (00:12:05):
Well, I might, I might tackle that. I think that as you say, the, the idea, the concept is, it seems directionally, correct. Seems, seems intuitive almost. I think that in practice, we didn't really get it right a lot of times, because if you think about what we're trying to, would be trying to do, we want to go intermediate to a far off dry cow into the, the fresh cow ration so that you're stepping up the cow in density. And I think a lot of the trend early on with the steam up rations was people went really wild on this, the steam up part. And so there was no real step there from the...there was a big step from the dry cow to the close-up cow, but then not as much of a step to the, the fresh cow. That's part of the problem, I think.
Dr. Jim Drackley (00:13:00):
The other issue is that the cows, we know now, that the cows are becoming catabolic somewhere in that last few days before calving. And so we're kind of working against nature by trying to push this real high, high energy density diet onto the cows when they're, they're gearing up to make the adjustments in metabolism that they need to, to divert nutrients to the mammary gland. So I think a lot of the work that we've done since then has showed that a more, a more moderate steam up-approach, or even, even a single diet that's kind of in the, in the middle can be just as effective and work with the cow better.
Dr. Bill Weiss (00:13:47):
You know, this has been an area that there's just a huge amount of research that's been done in the last 10 or 20 years compared to before 2000. So I think we've learned a lot on how to feed these cows. And it's improved. And I agree everything with Jim said, and you know, back then there was this idea that the rumen physiology or morphology had to adapt and all this stuff. And that's been pretty much shown to not really be that important, so.
Dr. Mike Vandehaar (00:14:16):
The rumen adapts really quickly.
Dr. Bill Weiss (00:14:18):
Exactly. Exactly. We don't need these three and four weeks, like we used to think.
Dr. Jim Drackley (00:14:23):
Yeah. And that, that German work that that was based on, the diets were almost entirely wheat straw. You know, there was just nothing fermentable in it. And so I think if we have typical diets that are gonna have some corn silage and some other more fermentable feeds, I don't think there's an issue with the rumen papillae and the rumen, and the rumen tissue adaptation. There's still an issue of rumen microbial adjustment. But as Mike said that, I think things change pretty quickly.
Dr. Mike Vandehaar (00:14:55):
I think another interesting thing, if I could add one on that one is that with the previous versions of the NRC, if you fed a high grain diet versus a high fiber diet, you'd see a pretty big difference in the predicted energy supply per kilogram of diet. With this version, starch depresses fiber digestibility. And therefore, when you look at two diets, one high in starch, one high high in fiber, the difference in predicted energy density or energy supply per kilo is not that different. And what starch really does is allow the cows that are really limited by gut fill, it allows them to eat more. But that's not a big problem for, for cows that are not producing a lot of milk around the time of transition. It's probably not gut fill that limits intake. It's something else; hormones, changes in metabolism that are going to happen. Right.
Scott Sorrell (00:15:54):
What about amino acid requirements? What did you guys change, if anything, with the amino acids in both the dry cow and the fresh cow?
Dr. Bill Weiss (00:16:06):
Nothing, because we don't, we don't know, at least in that sample, we don't. Those animals are still on a protein or an MP basis, not an amino acid, because we just don't know.
Dr. Jeff Elliott (00:16:18):
So can, maybe I can expand on that or take another question, going back to the previous question. That those close up rations we don't have to adapt. Part of that is probably also because we've gotten better at feeding fresh cows. Even though you're seeing, even though we don't know a lot of that, you know, compared to 20 years ago where we're doing things a lot better. So maybe my question is, you know, we don't know now, what do you think we, for the next NASEM in 10 years when you all come out of retirement and are writing that one, what what are we going to need for those fresh cows? What kind of information?
Dr. Bill Weiss (00:17:03):
I'll start, and turn it over. One is you always need a metric. What are you, what response variable? And so far, it's been pretty much, we feed a pre fresh cow and we look at milk production. Does that, and there's a lot more to this than just milk production or lactation on calf health, colostrum quality, all these other things we never look at. So one is we just got to develop good metrics to evaluate diets with not just, it's much more than just maximizing milk production.
Dr. Jim Drackley (00:17:36):
Yeah. I'd, I'd agree with that. I think in terms of the pre calving diets, I think we've, as Bill said, we've made a lot of progress and I think can do a pretty good job feeding them. I think there's, there's probably getting to be enough information now that maybe a meta analysis or two on things like colostrum volume and classroom quality could be, could be prepared in another, by another 10 years. In terms of the fresh cow. I think we're still, I think we're still defining things. In particular the, I think an area that's unanswered scientifically anyway, is the whole rumen fermentibility and, and how high of an energy density you can go with the fresh cows. A lot of people are still worried about, or nervous about, pushing very high starch rations in the fresh cow, but others will show you great results from pushing cows harder than some of our recommendations would say. So I think we still need more information on that issue of fiber adequacy and, and energy density in the fermentibility in the early fresh cow period. And that relates to then back to the amino acid question about metabolizable protein, metabolizable amino acid supply. If you can get cows to eat a lot of energy, you're going to make a lot of microbial proteins. So that, that, that helps out the MP side.
Dr. Mike Vandehaar (00:19:17):
And I would just add, I think how diets affect the hormones that affect partitioning and intake is something we still have more to learn about, especially in that transition cow.
Dr. Bill Weiss (00:19:30):
Yeah.
Scott Sorrell (00:19:32):
Bill, you were also involved with the minerals chapter. Anything changed with minerals for transition cows?
Dr. Bill Weiss (00:19:41):
Yeah, a bit. And again, this is- yeah, at the transition cow, minerals are much more than just meet requirements. And that's really what the NRC does is meet requirements. And you have the hypocalcemia isssue, which is totally- well not totally- but not, not meet requirements. You have to feed them special. There is a very, I think, good, good in depth discussion about ways to minimize hypocalcemia. But again, we can't come up with requirements for doing that. We say, you know, you can feed DCAD or you can feed low calcium. You can feed calcium binders. There's a lot of ways to get, get there. If, if you just look at requirements, I'd say the only one that changed appreciably would be magnesium. That's because of both better data on absorption and some, some maintenance requirement updates. But in general they haven't changed much. But again, this is a section where your thing, you got to read the book and find all these little fine tuning things that nutritionists need to think about that's not going to show up in the computer program.
Scott Sorrell (00:20:50):
You know, speaking of magnesium, I recall in your presentation, there was quite a bit of difference in of availability depending on the source. Can you expound on that just a bit?
Dr. Bill Weiss (00:21:02):
Yeah. It's you know, in the last one, I don't want to degrade that too much or say too much bad things since they didn't have the data we had. There's been, since that came out, I think it spurred a huge amount of magnesium research. So we, we had data they, they could only dream about. And they, they, they came up with some absorption coefficients that ended up being quite, actually quite wrong because of some calculations they made. So the, the absorption coefficients in general are much better now, again, because we had hundreds of data points and they had, you know, five or six, so huge data difference. But it's still on these supplements, magnesium oxide is a primary supplement. It's a manufactured, it is not a mined mineral, it's manufactured. And the way they manufacture it has a big effect on how good it is. And so that, that again is discussed in things you need to think about. The numbers in the book assume pretty good Mag-Ox if, but there's some pretty bad Mag-Ox out there. And that obviously would take different supplementation rates than the good stuff. So we don't have, you know, there's not in the feed library, there isn't a thing called good Mag-Ox and bad Mag-Ox, there's just Mag-Ox and users are going to have to adjust accordingly, so. And it is highly, highly variable.
Dr. Jim Drackley (00:22:28):
What accounts for those differences Bill? Is that impurities in the resulting product or, or what is it?
Dr. Bill Weiss (00:22:31):
It's part of it is particle size, which is easier to quantify, and that, but the big onr is, is, you know, they have to make this stuff and they have to cook it at a very high temperature. I can't remember 1300, 1400 degrees, for a very specific time point to drive off impurities and make that reaction. And if they cook too low or too, too short, it's no good, if they cook too long or too hot. It's no good.
Dr. Mike Vandehaar (00:23:01):
Yeah. I was going to say, I didn't know it was a manufactured product, but sometimes they look like little glass balls. You know, just very small, tiny glass balls, right.
Dr. Bill Weiss (00:23:10):
And that's been over cooked. And again, there's some very good companies out there that make very good Mag-Ox consistent, and then there's some other ones that aren't so good and you just, you know, find a good supplier that supplies good stuff, and, and stick with it. So.
Scott Sorrell (00:23:25):
Yeah. So Bill, you said size matters. Is, is it fair to assume that smaller is better here?
Dr. Bill Weiss (00:23:30):
Yup, and for minerals in general, smaller- matter of fact- almost every nutrient smaller is better, so.
Scott Sorrell (00:23:37):
Gentlemen, before we transition away from transition cows and make our way over to calves, is there any big areas that we've missed?
Dr. Bill Weiss (00:23:45):
I'd like Jim, to talk a little bit about fat supplementation, and especially in early, early lactate. You know, not many people do it to the dry cows, but early lactation. I, I get a lot of questions, is should we be feeding fat.
Dr. Jim Drackley (00:23:55):
Yeah. The older literature and kind of my, my storyline has always been that we should kind of go easy on fat supplementation after calving because it didn't appear like that supplemental fat would, would suppress body fat mobilization. And, and so you just end up with too much fat in the system to metabolize efficiently. Some of Adam Lock's recent research, however, would tend to point towards maybe some opportunities, more opportunities for feeding supplemental fat in the, in the early fresh cow period. I think part of it is just we're, we're talking about smaller amounts of fat in general than we were maybe 15 or 20 years ago. So it maybe is closer to what, what I was recommending previously as well. But I think that there's, there's you know, some, some better evidence from his studies and some of other people's that, that a moderate amount of fat could be useful in the, in the fresh cow diet, as long as we're not going, staying in the, you know, 5% of total diet dry matter range for the amount of supplemental fat.
Dr. Jim Drackley (00:25:16):
Pre-partum, again, I mean there was some work done there and I just, I just, I don't see much benefit in that. There doesn't seem to be any any specific metabolic signaling that fat in general gives us that would make it a more desirable source of calories than, than starch or fiber. The, the work with the essential fatty acid products I think is, is very interesting from a scientific standpoint, but from a practicality standpoint, I think there's still some issues with, with getting the product into cows, and whether it's truly cost effective or not.
Scott Sorrell (00:25:57):
Bill, we've hit about every nutrient category except vitamins. Are there, are there any vitamins or vitamin like compounds that you'd like to discuss relative to dry cows?
Dr. Bill Weiss (00:26:10):
The only change was in vitamin E, pre-fresh, and that was, you know, there's good data showing reductions in mostly metritus, but also mastitis post calving. So that was bumped up about a thousand units a day. There's discussion of, of potentially increasing vitamin A, but, you know, one thing with NRC is they, they actually expect us to have data to back up what we say, and on the vitamin A there's just not much data showing elevated pre-fresh does anything. There's discussion on choline, both pre and post. It's not, we don't give a requirement for that, but there is discussion. And there's also discussion on methionine, pre and post, for things other than just amino acid or protein synthesis. So there's discussion on a lot of these things, but they're not explicit requirements. They're discussions.
Scott Sorrell (00:27:06):
All right. Very well. Well, if it's okay with everyone, let's transition the calves then, and I'll start with Jim. Jim, what are the big changes related to calves and, and what kind of implications will that have for feeding calves going forward?
Dr. Jim Drackley (00:27:23):
Yep. Well, the calf chapter was, was extensively revised. We built a new model for predicting the, the energy requirements and predicting growth from the, from the amount of feed offered that I think does a much more accurate job of predicting calf performance than the previous model did. So that's a big change. We have a starter intake prediction equation or, or equations that will allow estimates of starter feed based on the amount of milk that the calves are consuming and their, their size or age. The mineral requirements have been, have been better defined. Before the requirements were all just listed as percentage of the diet or percentage of a milk replacer starter. And with Bill's help, we, we actually built requirements that are based on a factorial approach or, or adequacy of the of the mineral. A few adjustments on the vitamins; vitamin D was increased, vitamin E was increased. I think those are probably the biggest factors that were changed. And I think it, just in terms of implications, we're going to be able to do a lot better job of predicting what our calves are or should be doing with a given level of feeding. The, the text is expanded too to discuss more issues about rates of milk feeding and, and we added some information on automated calf feeding and group feeding, which was requested of us. So the, the text has been expanded as well.
Scott Sorrell (00:29:19):
Is there any discussion on optimal growth rates?
Dr. Jim Drackley (00:29:22):
Yeah. There's, there's not really a discussion of optimal growth rates, per se. I mean, it's discussed how, how the amount of milk that we supply will affect growth rate. And you know, in, in general it looks like the more you feed, the more growth you get. Whether that's a positive long-term, there is some discussion on that, but as far as, as trying to set an optimal growth rate, we didn't, we didn't tackle that.
Dr. Jeff Elliott (00:29:53):
Yeah. I wouldn't mind hearing your, maybe philosophical comment on this, but on the optimal growth rates, maybe from all of you. Can we grow them too fast? And, you know, and I think, I think of two things, and it's more on the poultry side. You know, I've traveled to China a great deal. And here, the chicken breasts, they're not quite as large, but like just really tender meat. But also thinking about woody breast. And, you know, we hear about that in the monogastric realm, and it's potentially due to growing the, the poultry too fast. So do you think there could be some major disadvantages to growing our heifers too fast. But I will add the caveat first, and I'm not sure that's a problem here in the US historically because I think we've short changed them over all these years, but if we were to ever get to that stage...?
Dr. Jim Drackley (00:30:49):
Yeah. From, from what we know now, it's hard for me to imagine that we would ever get to that point from a practical standpoint, at least. You know, experimentally, we, we have calves that are growing more than, more than two and a half kilos a day in the early milk fed period, individual calves. Whether that's too much, or whether there would be some, some negatives that would show up, I don't really know. But my, my bias is that I don't think that the early growth rate is going to have any, any negative outcomes, but I don't know. What, what do you think about that, Mike?
Dr. Mike Vandehaar (00:31:25):
Yeah, I agree with you, Jim. I don't, if you just think about I mean, we fed veal calves for years, and I realize that they, we slaughter them at a young age, but I don't really think you see soundness problems with their growth. Now I'm not an expert on veal calves. I have, you know, you look at beef calves that are nursing, a dam that produces a lot of milk. You don't see a problem with soundness of growth. I mean, they just grow big and fast and they look nice. So I don't think that feeding calves for rapid growth is a problem. I think it could potentially be an issue for older heifers, which we can talk about later, but I don't think it's a problem for calves. In fact, the data even says that faster growth is probably good. Right? So, for later milk production. So, whether you need two, two and a half kilos, I don't know if that's any better than one kilo, but.
Dr. Jim Drackley (00:32:23):
No, no, that's just individual calf basis. So I don't think we'd ever get there on an average.
Dr. Bill Weiss (00:32:30):
You guys think there's- we get this question a lot too. Is there a breed difference on, on what you did? I know the rate of growth will differ, but do you think you'd get the same response with Jerseys with this rapid growth or increased growth as we do with Holsteins?
Dr. Jim Drackley (00:32:48):
Yeah, I think, I mean, there's, there's again, not a lot of research evidence, but certainly what you see in the field is people are making Jerseys grow pretty rapidly, too. The, one of, the couple studies that are available, you know, those calves gained pretty rapidly and, and seem to respond, in general, in the same way.
Dr. Mike Vandehaar (00:33:14):
Yeah. I agree with Jim.
Scott Sorrell (00:33:17):
Kind of changing directions just a little bit. Was there any thought given to epigenetics? And while we're kind of talking about the dry cow and heifers. And is there any discussion? And if not you guys have any thoughts related to that?
Dr. Jim Drackley (00:33:32):
There is a couple paragraphs discussion in the text that talks about possible epigenetic effects. Specifically related to different fatty acid profiles for the dam, and methionine. And you know, there there's, I don't believe there's much on the choline information because that came out a little bit later in the process, but certainly the general, general idea is, general principle is that it's something that's an emerging field. That's kind of what we can say at this point is, is you know, there's, there's a lot of interest in it, but there's not a lot of data to this point.
Dr. Mike Vandehaar (00:34:13):
We should have added that one to our list of things that they need to do for the next NRC.
Dr. Jim Drackley (00:34:18):
Yeah. We should have that's right. There'll be a lot more information by then.
Scott Sorrell (00:34:22):
Is that a long list, by the way, just kind of curious?
Dr. Mike Vandehaar (00:34:26):
Depends how much we keep drinking and talking.
Dr. Jim Drackley (00:34:31):
And whether we're going to be on the committee or not.
Dr. Bill Weiss (00:34:36):
Yeah. One of our specific charges, was to address future research needs. So every chapter has some stuff on what we think needs to be studied. So, some chapters more than others. But that was our, one of our jobs.
Scott Sorrell (00:34:53):
What are the thoughts that we have related to calves?
Dr. Jim Drackley (00:34:56):
I think one of the, one of the things that's a black box yet in the area of the calf that needs more research is the, the whole series of changes that take place around weaning. So as the calf goes from milk and starter fed animal to solely a ruminant, there's tremendous changes that we know are happening in the, in the digestive tract, but we don't really know the time course. We don't know the implications for requirements and that's, that's a real black box. But one of those things that the industry is probably not going to fund because it's there, there's likely not a, a good product or two at that at the end of the line there.
Dr. Bill Weiss (00:35:39):
I guess just as an example. You know, and a calf absorbs about 50% of the copper she eats. A cow is 5%. Well, when does it change? Who knows? I mean.
Dr. Jim Drackley (00:35:51):
That's a great example.
Scott Sorrell (00:35:55):
Yeah. Jeff, what else you do you have?
Dr. Jeff Elliott (00:35:57):
Yeah, just thinking about that last comment. So I just want to make sure I heard you right, Bill. So you're saying a cow absorbs about 5% of the copper that she consumes, but a baby calf about 50. So somewhere between say weaning and maturity, there's quite a transition there.
Dr. Bill Weiss (00:36:18):
It would be, once the rumen starts functioning, it'd be sooner rather than later. But because the rumen is making all these changes, but again, is it a week after they transition or a month? And it, it can have a big, you know, do we feed it like a calf and have very low copper because we assume they absorb a lot, or do we feed her like a cow because we, and feed them a lot because they don't absorb much? And, and that has consequences, deliver accumulation and other things. So I think we just took the average. I think that's pretty much what we did cause we didn't know what to do!
Dr. Jim Drackley (00:36:53):
I think we punted down that one. Yeah.
Dr. Mike Vandehaar (00:36:56):
I think the other thing that the next NRC will probably have more on is how to feed the calf in the first few days. The whole idea of transition milk, there's specific things we could feed to enhance immune function, gut development in those first few days. Yup. And I just want to make one comment about the calf chapter, which Dr. Drackely did a lot of the work on the calf chapter, is I think it has more references than any other chapter.
Dr. Bill Weiss (00:37:31):
It's got a lot!
Dr. Mike Vandehaar (00:37:32):
It's got a lot, so it's a very thorough review.
Dr. Jim Drackley (00:37:38):
Well the whole, the whole NRC, the whole book as we're calling it, it's going to be like reading War and Peace, I think for people.
Dr. Jeff Elliott (00:37:47):
So, so with all that, those references and that, apparently, then research that we'd done. One thing that just drives me nuts in the field is that a farmer or a dairy producer will spend so much time and effort and money to select that perfect semen match for that cow, and then as soon as that calf is born, they forget about it.
Dr. Mike Vandehaar (00:38:13):
Some farmers.
Dr. Jeff Elliott (00:38:15):
Yeah, I should say that.
Dr. Mike Vandehaar (00:38:17):
I was, I tried to do research on a farm two years, last two years ago or something, that was a large farm. 60 cows calving a day. And I, we were looking at a way to improve immunity in the first few days. Their calves were so well taken care of. I mean, there was no way we could, we could- we had 60 calves per treatment. We couldn't show any positive benefit of anything, probably because they were doing such a fantastic job. Colostrum within 15 minutes, another batch of colostrum within the next 10 hours. So there are some farms that are really doing it right.
Dr. Jim Drackley (00:38:57):
No, I agree.
Dr. Jeff Elliott (00:38:59):
Definitely getting better.
Dr. Jim Drackley (00:39:01):
But there's still too many, like you say, Jeff, that, that are not doing the job that we know can be done. Right.
Dr. Mike Vandehaar (00:39:09):
And how do you fix that? I don't, I don't know. Yeah.
Dr. Jeff Elliott (00:39:14):
Yeah. One last question on the, on the calves. Any, any discussion on the individual feeding versus the group feeding and how that might affect requirements?
Dr. Jim Drackley (00:39:27):
Oh, there is, there is a section in the text about that. As far as how it affects requirements, probably not greatly, if you look at an individual calf basis, it's still, you know, nutrients in and and so on. But some of the other issues that behavioral issues, the management of auto feeders, the environmental issues, ventilation, and so on. We, we touched on all of those that are outside of the scope of nutrition per se, but certainly important to make a system like that work.
Scott Sorrell (00:40:04):
And Jim, I have one final question as well. Is, can you talk a little bit, bit about the NASEM recommendations for minimum milk solid feeding rates to calves?
Dr. Jim Drackley (00:40:12):
Yeah. So we came up with a recommendation that calves should be fed a minimum of one and a half percent of their body weight as milk solids of their body weight at birth. So, you know, whether or not that makes a huge difference in the field is, is it's hard to say. If you're looking at a, like a, an 87 pound calf, which is the average of a lot of people's work, it may, it raises the recommendation from a pound and a quarter to 1.3 pounds. So it's not a big deal. But if you're looking at a little heavier calves or, or take a little more broadly, then it, it, it might might mean that it's an appreciable increase for some people.
Scott Sorrell (00:40:55):
All right. Thank you. Before we transition over to heifers, any final comments or thoughts we might want to share on calves?
Dr. Bill Weiss (00:41:04):
It's a big change, is all I'm gonna say. It's probably one of the biggest revisions of every, every thing we did. It's major, major changes.
Scott Sorrell (00:41:15):
Very well.
Dr. Mike Vandehaar (00:41:17):
And your predictions are really quite remarkable. Using the data sets you have, you know. Whether that all proves out in the field, I don't know, but for the data that you have, the equations do a nice job,
Scott Sorrell (00:41:33):
Mike, we're going to transition then to heifers. As we dig into that, maybe you can just kind of outline some of the biggest changes there and, you know, the implications that's going to have for, for feeding heifers.
Dr. Mike Vandehaar (00:41:44):
Probably the biggest change we made was that the composition of gain is based on data from Holsteins instead of data from growing beef cattle. We've been using beef cattle as our reference animal for a lot of years. And now we have enough data from Holsteins that we could use dairy data. We increased the maintenance requirement for heifers, consistent with what the NASEM model in 2016 said for beef. What the NASEM beef said about dairy breeds, and consistent with what we did for cows. Do we have a lot of data in heifers to say from our side that, that we looked at that that really supports that? No, but you know, I think between the NASEM model for beef and what we did for cows, I think it makes this a reasonable thing to do. The intake equations are definitely better than the last model.
Dr. Mike Vandehaar (00:42:52):
They aren't in the heifer, the growth chapter, they're in the intake chapter. But they are equations that are more recent and they include feed factors or at least NDF. We made them so they're size scaled. So they should hopefully work okay for Jerseys as well as Holsteins. That's true for all of the, the growth chapter is everything was size scaled so that, that it should hopefully work for Jerseys as well as Holsteins. Although everything we have is really based on Holsteins, not Jerseys. There just is not, there's not much data with Holstein heifers; there certainly isn't much with Jersey heifers. We simplified the size scaling system, and I think that was a big improvement. So, so it's a lot easier to understand how we expect the requirements to change as animals get as, as animals grow.
Dr. Mike Vandehaar (00:43:51):
And we just fixed a few problems in the last ones. For example, in the last model, empty body gain was assumed to be nearly the same as average daily gain in a heifer- 95.6% of average daily gain, which we know that's not true. And so to, to start building a better model, at least we got to have some of our basic fundamental facts right. So I, you know, will this make a dramatic change in how we feed heifers? I don't know that the diets are going to be that much different. In fact, there will be times that I'm sure that there that is probably not going to work. Okay. We don't have enough data to say that this is going to be accurate, especially in all situations. But, but in terms of looking at relative changes, you add forage, what do you expect to have happen? You add non forage NDF, what do you expect to have happen? You add grain, what do you expect to have happen? How growth rate might change? I think it'll do a better job of that. And we have a system we can build forward on.
Scott Sorrell (00:44:59):
Do you have any thoughts or opinions on- we'll go back to the concept of optimal growth, right? We know that first calf heifers, even in even second calf cows, they're still growing. And so is it, is it more optimal to have them put on that growth before calving? Or do you have any thoughts or opinions on that?
Dr. Mike Vandehaar (00:45:21):
Well, if so regarding the optimal body size at first calving, there's not- surprisingly, there's very little data to say, very little research to actually say one thing or the other on that. The few studies- and by that, I mean, there are studies that are correlations, but they're not causative. So there are a few studies that actually show that if you have heifers calve at a heavier body weight. And I don't mean fat, I mean, sound growth, normal body condition, animals that come into their first calf being larger, closer to mature body weight will produce more milk than those that are smaller. But of course there's, there's costs both ways, right? So if you can get an animal into the milking stream earlier, that's less time that you have her in a non-productive state. So there's that in terms of profitability, I'm not sure what the answer is for, and what we have in, in the, the chapter is that somewhere around 82% of mature body weight is a good time to get her into the, to the milking stream. You want to talk about optimal growth earlier in life, that's a different question. We do have a section on that.
Scott Sorrell (00:46:37):
So let's talk about that then.
Dr. Mike Vandehaar (00:46:38):
So there is a section on optimal growth rates for heifers, and the critical time is between probably sometime after weaning- I don't know when- and about the time of puberty or maybe breeding. It's not clear cut then either, but there's a time when the mammary gland is growing at an allometric growth rate. So it's growing faster than other body tissues. There's really good data to show that. Somewhat controversial about whether you can grow animals too fast during this time. But I think everybody who does this work, probably even though publicly, we sometimes disagree with each other. There's less a disagreement when we get together with each other. And right now there's no study that has shown that if you grow heifers faster than about 900 grams, certainly a kilogram per day during that critical time period before puberty and after weening, that you're going to get as much milk from them as a cow.
Dr. Mike Vandehaar (00:47:52):
If they grow with proper, it's probably related to the fact that when heifers grow really fast during that time period, they often grow too fat. And that might be a bigger issue, but there's not a lot of data to say one way or the other. But it's probably when they grow too fat. So if you can get a heifer to grow nice and lean, and she's growing fast, she might be okay. But in the chapter, we suggest that at least you use some caution when you do that, because we don't know. And I have friends who feed heifers who'll say, oh yeah, we can get them grow three pounds a day, you know, in that five, six month range. And so then they produce milk like crazy as cows. Well, sure. How do you know they wouldn't have produced more if you had slowed them down? We don't know.
Scott Sorrell (00:48:45):
Yeah. And I got to believe there's a lot of variation depending on breeds, right. And there's more breeds and just Jerseys, you know. 25% of our audience on our webinars, they'll come from Europe and there's a lot of different breeds that they use over there. So yeah I'm wondering how we get our arms around that. Do you talk about-?
Dr. Mike Vandehaar (00:49:03):
We will just say that for optimal growth. We, we tried to put everything in perspective related to the mature body weight of the animal. So I don't remember that number off the top of my head, but we talked about the gain per day as a percent of mature body weight, so that you're looking at a different number for Jerseys than for Holsteins or for some of these other breeds as well.
Dr. Jeff Elliott (00:49:28):
Did a lot of...you said that previous data prior to this version came from beef animals. So, so I almost laugh. It makes me wonder if that's why, when I'd used, you know, when I used to walk those heifer yards and see those puberty to, you know, almost ready to calve animals, they were so fat, you know, if you were using the beef numbers. So now if we've got the Holstein numbers, is that the reason also for the increased maintenance energy? Is there..?
Dr. Mike Vandehaar (00:50:03):
Yeah, so the maintenance energy is higher for dairy breeds than beef breeds. I think there's not much question about that. Why? You know, perhaps because we've been breeding our animals to be really metabolically active and superstars. Superstars at making milk, but then they also have all the right hormones to grow faster, too. Our animals don't put on as much fat. Their composition or their gain is more protein and less fat compared to beef breeds. So that's probably related to it, as part of it anyway. In fact, you know, even with ours, if we simply used the, the gain, the protein gain as our sole determinant of deciding how much protein to put in a heifer diet, the protein content of our diets would be lower. We ended up putting in a minimum metabolizable protein to metabolizable energy ratio for heifers. And that minimum ratio comes into play for, for most of the heifers once you're past about four months of age, I think.
Dr. Mike Vandehaar (00:51:26):
There's data to support that, okay. There, we cite the papers to support that in the chapter. Why might that exist? Well, it's possible that that protein during that critical time of mammary development is doing more than just helping to support muscle tissues grow, right? Maybe it's doing something at the level of the mammary gland we just don't understand. That it's helping the gland get ready to be active cells that will someday be able to really start to turn into the cells that make milk.
Scott Sorrell (00:52:06):
Mike, we were talking about research gaps previously. What do you think some of the biggest research gaps are related to heifers?
Dr. Mike Vandehaar (00:52:15):
Yeah, so we, we do list that in the chapter. And the problem with a lot of the studies that are in the literature is that they often seem to be missing some critical component that we really need to be able to put into our models. So maybe they do a good job of describing growth, and maybe even composition of gain, but they don't have anything about the composition of the forages. And the diets aren't well-describe. They might have been studies that were done by somebody who wanted to look at how diets affect future milk production. And they figured, well, it's not so important to put all the details in regarding the nutrition part. So it just seems like they're often holes in any study you find to be able to use this to really help build a model. And, and the problem is we don't have a lot of data to say what the conversion of metabolizable energy should be to net energy. Net energy, for maintenance or energy, net energy for gain.
Dr. Mike Vandehaar (00:53:27):
We don't have a lot of good data to say what the ratio or what the conversion of metabolizable protein is to retain protein or net protein. And so we had to rely on either old versions, or the NASEM beef model, or some combination of the two to come up with those numbers. And that's, so that's the biggest hole we have. And we really need more studies with heifers where all of the important information that goes into a model is put into the paper. And sometimes that means you're going to have, that research, you will have to fight with the editors. Because sometimes the editors are going to say, why is this in there? And then the people say well, because NASEM, the next NASEM needs it. And sometimes we don't know what the next NASEM is going to want. So maybe we need to. You know, dairy, dairy science now gives us the option of putting in tables or information that just go into an electronic supplement and we should include that stuff. Yeah.
Scott Sorrell (00:54:29):
Bill, Jim. Anything you'd like to ask Mike on this topic?
Dr. Jim Drackley (00:54:35):
I might just make a comment, kind of back to the unknowns or things that we need more research on. That we had hoped to make the calf requirements blend seamlessly into the heifer requirements. And they don't. There's, there's still a gap there based on the, the two different systems where they come together at about 125 kilos of body weight. And that's, again, it's because Mike's extrapolating back on the heifer end to the low rates, and I'm extrapolating up on the calf side to those body weights, and there's no real good data to make those connections. So that there, there's still going to be a kind of a crossover for, for people at some point when you stop using the heifer- or the calf model, and start using the heifer model.
Dr. Mike Vandehaar (00:55:31):
Yeah. Really good point. Because when you get to that crossover period, you'll see the protein percent of the diet suddenly jumps up, as I recall. Which I'm sure is probably it's probably jumps up too much. I'm sure the heifer model is probably wrong right there. One of the reasons there is that we put in a crude protein requirement. The model is really based on metabolizable protein. And in the tables, it has a crude protein requirement, but that's pretty much irrelevant when you start to use the software. And probably in those younger heifers that convert, we used a con- in the tables, we said, CP is converted to NP with like 62% efficiency. And for those younger heifers, it's probably higher than that.
Dr. Jim Drackley (00:56:18):
We used, we used 70%. Yeah.
Dr. Mike Vandehaar (00:56:21):
So that's part of it. And maybe we should have dropped it from 70% to, gradually, to 62% as the animal got older. Right. But it's, you know, it's kind of a guess on how you do that. So, yeah.
Scott Sorrell (00:56:35):
Very well, gentlemen, I just finished my bourbon. So that, that means it's last call. And so, what I'm going to do for last call is just kind of ask each of you to kind of wrap it up with, you know, 1, 2, 3 things that the audience should take away from the discussion this afternoon. And Jeff, I'm going to start with.
Dr. Jeff Elliott (00:56:55):
Okay. You know, great conversation. Appreciate it. Appreciate being on here. Few things I took away, and we started with the term directionally correct. And that, that's what I, when I did more nutrition work, that's what I always tried to do. I knew I wasn't ever spot on, but anytime I made a change, I wanted to be directionally correct. And that's kind of what I heard from these guys, that we still got some changes that need to be done. We need more research, but we're, we're going in the right direction. So I think that's key. I think also that the, for the last month of pregnancy, that the there was the increased energy and protein requirements. So just putting more pressure on that cow, that everything that we can do for that animal is key. And then I liked this, I like this last conversation about the heifers. And, and getting really close or really being directionally correct with them. Getting away from the beef side, having more Holstein data. I think that's going to help a lot more than we realize.
Scott Sorrell (00:58:09):
Yeah. Thanks Jeff. Jim, what thoughts do you have?
Dr. Jim Drackley (00:58:14):
Oh, I think I'm proud of the calf chapter, the calf model, because I think it does a good job of predicting at least research data. And I'm anticipating that it's going to do a good job in the field. I think it is directionally correct. I would also point out, and I didn't mention before, but the the requirements in the calf section are based actually on composition of gain data from slaughter studies with Holstein and Jersey calves. So we're like, like Mike's discussion on the heifers, we actually have good data now to, to base the requirements on for a typical typical growing dairy heifer or beef steer based on these data. So I think the requirements and the, the conversion of nutrients into gain are much improved. And I look forward to see how the, how it works in the industry.
Scott Sorrell (00:59:22):
Hmm, good. Mike.
Dr. Mike Vandehaar (00:59:26):
Yeah, I think I agree. I'm, I'm happy with what happened in the heifer chapter. I'm not quite as confident about how it will always work in the industry. And I'm anxious to see how that works, because I know we had some, some, just some shortcomings in the data that are available to us, but, but I at least feel good that the composition of gain equations are now based on Holsteins and we have a platform which we can build upon.
Scott Sorrell (00:59:55):
And Bill's a Chair, I'm going to let you put a final bow on this.
Dr. Bill Weiss (01:00:00):
Well, on the transition cows, I just, you know, it's better than- we made improvements, but there's still a lot of art in feeding a transition cow. It's not all science. And you can't just use the computer to feed these cows. And again, I want to urge people to read the book because there's a lot in there on stuff people should, it may not tell you what exactly to do, but it's going to tell you what to think about. And again, there's still a lot of unknowns in this, how to feed these cows correctly. There's a lot of ways to feed them correctly. And they just, again, use, there is a lot of art to feeding a transition cow correctly?
Scott Sorrell (01:00:37):
Yeah. So there's a lot of different avenues we could've gone down today, a lot of great conversation. Unfortunately, we didn't get to everything. So, well, I'm going to just look forward to the next time we're together in a real pub, we're going to have to do this all over again. So, won't have the empty glass anymore. So I want to thank you gentlemen, for a delightful afternoon here at the pub. Also want to thank our loyal listeners for stopping by once again to spend some time with us here at the Real Science Exchange. As a reminder, we will continue breaking down the new 2021 8th revised edition of the Dairy NRC over the coming weeks. Be sure to subscribe. So you don't miss any of the new episodes. If you'd like to pre-order a copy of the the new NASEM and receive a 25% discount visit balchem.com/realscience, and
Scott Sorrell (01:01:28):
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