Transcription
[Music]
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 nutrition.
Hi, I'm Scott Sell, and I’m going to be your host here tonight at Real Science Exchange. Tonight, we're taking a deeper dive into one of our favorite segments, and that would be the Journal Club. We're joined by Dr. Adam Lock from Michigan State University to discuss his paper titled "Milk Production Responses of Dairy Cows to Fatty Acid Supplements with Different Ratios of Palmitic and Oleic Acids and Low and High Fat Basal Diets."
But before we get started, I'd like to make a few introductions. First, Dr. Bill Weiss. Bill, at the risk of alienating the majority of our audience, I would like to compliment you on your scarlet shirt. It was not a random choice!
And also, I would like to ask you, what did you think of that game last Friday?
They were playing extraordinarily well. It was a great game, exciting, and the right team won. So, it was a great game!
Yeah, exactly! I was in the stands very close to where that last fumble and run back took place. I made it down to Dallas, so that was quite a bit of fun.
So, thank you to our audience for a bit of patience there. You know, I know us Ohio State fans are insufferable, and we’ve got a bad rap, and it’s deserved. But Adam, I promise you, when Michigan State makes it to The Natty, we will do a whole podcast on the Spartans around here.
It's basketball season!
Well, that's true! We celebrate basketball here as well at Real Science Exchange.
With that, why don't we go ahead and introduce Adam? Adam, you're one of our favorite guests. Thank you for joining us here. Anything in your glass tonight?
I do, Scott, thank you! I always have my mug of tea here, so I always have my mug of tea. I just returned from England, so I've got a new stash of tea. But something else I also brought back from England is a little bit of Bushmills whiskey from Ireland. That was one of the last places my dad and I visited on a work trip for me, my late dad, and we bought a couple of bottles that you could only get at the distillery there, so that's kind of got a special meaning to me.
Very nice! Awesome! Any milk in that tea?
Oh, there's no other way to drink tea! I haven't picked up that habit yet, but I must say, being in the dairy industry, I should give it a try.
Bill, I kind of skipped over you. What's in your glass tonight?
Well, I have a beer from Braxton Brewery called Spur American Lager. It's made right across the river in Covington, Kentucky. Very, very tasty!
All right! And I'm enjoying this. This is from a local brewery, and it's called Log Tavern Brewery, and this one's called Hartford Haze. So that's what I'm enjoying tonight. The reason I've got it here is that I'm hosting a party this coming Monday to watch The Natty, and so I've got several growlers of some of the local beer on tap.
Before we get started here, I also need to introduce our co-host. We’ve got Dr. Clay Zimmerman back with us once again.
Yep, welcome Clay!
Thanks, Scott! I was going to say, you keep mentioning The Natty, Bill. That's where you live, right? They kind of got that confused for a while. Sorry about that!
This is our first podcast recording of the year, so before we get started, guys, what I'd like to do is raise our glass to an awesome 2025.
Cheers!
Cheers!
[Music]
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So, Bill, you've picked another great paper, so why don't you just start off by diving right in? Give us an overview of the paper and why you picked it.
Okay, well, this is a shorter paper in JDS Communications, so these are brief and to the point, which I like. I'm getting more into brevity rather than long papers. I think it's an important topic; it's answering an important question. And again, these are limited in scope, but that doesn't mean they're not important because they answer a very specific question.
I used to get this question similar to this: what's the value of supplemental fat when the basal diet is also high fat? So, Adam, I'd start with you. The question I always ask first is, what was your hypothesis and what was the objective of the experiment?
Yeah, thank you, Bill, and thanks for the opportunity to talk about the paper. Well, I think, as you know, we've been working in this area now for probably a decade around different fatty acids, supplemental fatty acids, and milk production. So this specific study is kind of an incremental step from some previous work.
We've done two previous studies where we had looked at high and low-fat basal diets and how they would interact with different fatty acid blends. In both previous studies, we probably took the more practical approach of high and low-fat diets where we either had whole cottonseed or soy hulls.
From a more basic sort of side of that, there was always the concern about whether that also impacted rumen fermentation and having some of the responses. So could we truly call those just low and high-fat basal diets? They were really whole cottonseed and soy hulls.
In this study here, Alicia, and I should mention Alicia Bales here, was the first author on this, and you have seen a number of her PhD papers come out recently as well. She led all of our higher oleic soybean work as well. This is one of her first papers, and in this one, we actually truly wanted to try and make the difference between those basal diets and the fatty acids.
So we either used whole cottonseed or cottonseed meal and cottonseed hulls to try and balance the fiber and protein side of those ingredients as well. So we had the low and the high-fat basal diets, and then we utilized two different commercially available fat supplements that had different ratios of palmitic and oleic acid.
We've done a lot of work on those before with the idea that both of them should increase milk production, but depending on the level of milk production, you could see differences between those. But as you alluded to, the idea of if I have a high-fat basal diet, do I even need supplemental fat? That’s kind of the very applied question there. Or if I don't have access to some of those, am I better off putting in a supplemental fat?
So that's kind of how we got to this point here. Now, the fat you added was about 1.8%, and the difference between the high and low was about two units or so. So with the high fat, it was about two units higher in fatty acids than the control.
So, yeah, it wasn't, you know, the high-fat basal diet wasn't particularly high, but then when you added another 1.5% supplemental fat on top of that, we got up to over 4.5% fatty acids in the diet. In both diets, we added our goal was to add 1.5% supplemental fatty acids.
In the treatment that we called the 6030 blend of palmitic and oleic acid, that was a calcium salt. So the actual amount we were adding was a little bit more than in the product, which was the 810 P blend.
Yeah, I think it was 9% whole cottonseed, so that's a fairly typical level. It's not the highest level, but fairly typical.
And then we just published a recent study doing a dose response of cottonseed, and in the 8% to 16% range, we got some nice production responses. So we're not too high. You know, in hindsight, could we have gone a bit higher? Maybe, but one of my goals here with all this work is to keep it commercially relevant or practically relevant.
We don't like to go into a lot of statistics, but the design, just the experimental design, not the model or anything like that, was a little bit different from what a lot of people use. Could you explain that, and again for non-statisticians?
Well, I'm a non-statistician, so that's an easy one for me! I was worried you were going to ask me some statistical questions there. I always surround myself with good people that are very good at statistics.
Yeah, so this was the third time we'd run a study with this design. The first time we did it was with Jonas Tuser for his first PhD, and actually, Dr. Norman S. Pierre helped us set it up, someone you're all familiar with, of course.
So it's a split plot Latin square. In this case, we had 36 cows, sorry, and we split them into two groups of 18. That's where we had the split plot. We either had 18 cows on the low-fat diet or 18 cows on the high-fat diet, and those cows never changed off those diets across the whole study.
Under each of those split plots, we had a 3x3 Latin square. So we had our control, no supplemental fat, and then we had what we called our palmitic enriched treatment and then our oleic acid blend.
Each cow within that split plot saw all three of those treatments. These were 21-day periods, so very typical sort of Latin square dairy nutrition period length. The idea there is that we can start to look at interactions between basal diet and the different treatments.
We've done that with this now and also when we've had a 4x4 Latin square. One of the benefits here is, you know, if you tried to run every cow through every treatment, we'd be getting up to a minimum of six periods. Cows might be getting too far out in lactation.
So what we often have done in some of these studies, the factor that we think of, which might be the cleanest factor to look at here, low versus high fat, we made that our main split plots. Then our other questions of interest, whether it be different fatty acid profiles or a factorial design, we would put those in the Latin square.
It also reduces the adaptation adjustment; they don't have to switch so much, and so I think that's a big benefit of these things too.
Yeah, that's a very good point.
We'll go into the diets a little bit, not too much. I had this one burning question here, and that is you guys in Michigan like high moisture corn. Do you think—and this was a pretty hot diet—I thought—and you still had really good milk fats. Is that surprising?
Well, 31% starch with high moisture corn, yeah, we formulated a 30, and by the time we got all the ingredients back at the end, we were a little bit higher. This was probably actually one of our last studies that we had high moisture corn in.
You know, we had some storage issues at the dairy farm, so since then, we've not been using high moisture corn. Ever since I came here, a lot of these studies had a pretty even blend of dry corn and high moisture corn, especially in the higher producing cows.
I mean, these cows are up 50 kilos, so what, 110 pounds? So, you know, pretty good producing cows. We have good forage in these diets as well. You know, forage NDF, I guess it's not overly high, but there's some good buffering there in the protein packs we had.
We work with a commercial company; they help put our diets together. So I think this would be a fairly normal milk fat for where we would be seeing. Actually, compared to where we are now, this study was done in what, 2019?
I think 2020, I think it was. You know, our herds are averaging a bit over 4 now in milk fat. It's, you know, between 37 and 39. Again, with that much starch from high moisture corn, I was impressed.
It was a very good milk fat. We've been blessed here, I think, for a long time now with some very good genetic cows here as well, and that's why we've been fortunate to be able to do a lot of these studies on very high producing cows as well.
I was going to say, I think we need to adjust our thinking a little bit on where fat should be, right? Like right there, a month now, the US milk supply is averaging a 4.2.
Yeah, it's amazing how much up! I saw an article in Hoard's recently that 2024 was the first year that the US had averaged over 4% going all the way back to 1924 when records started.
So, yeah, it's amazing what genetics and nutrition can do.
Yeah, they certainly go hand in hand.
Well, I guess we can jump into the production data or the data. And I guess first of all, you know, the first question I always ask is interactions. Was there any substantial interactions between basal fat and fatty acid supplementation?
Yeah, that's always a good question. So, you know, when you design the study, this type of study is designed to look at interactions. If we see an interaction, the main effects aren't certainly as important at that point. You want to start breaking it out and looking at those interactions.
The interesting part of some of these studies, to be honest, we didn't really see too many treatment by basal diet interactions. The only one that was really a trend for significance there or significant was for milk yield and milk lactose.
Even that trend is an interesting one where the fat supplements both increased milk yield in the low-fat and the high-fat diets, but the actual magnitude of that increase was more in the low-fat diet than it was in the high-fat diet.
So, it wasn't an opposite type interaction, which is what you often think of. In the low-fat diet, we actually found the high palmitic diet increased milk yield more than the oleic acid treatment, whereas in the higher producing cows, they gave similar responses.
If you would have asked me, I expected that if you were already feeding a basal fat, a higher fat, then you add fat, I'd expect a smaller marginal effect, and that's what you get. It wasn't as much; they weren't that much different.
I mean, roughly calculating, one was about a half a kilo. The high-fat diet, when you added fat to the diet, you got about a half a kilo of milk. With the low-fat diet, you got about 8.8 kilos. So it wasn't a huge difference, but kind of what I would have expected.
And then when you take that out to sort of fat-corrected energy-corrected milk, we don't actually see the interaction at that point. We see the main effects of those treatments.
Overall, to be honest, the responses to the fat treatments—because nothing ever works exactly how you expect—but the actual overall kilograms or pounds increase weren't as great in this study as what we've seen in some previous studies.
Some of that depends on your starting cows as well.
So if you want to just kind of—oh, go ahead, Scott, sorry.
Go ahead, Adam.
I was curious, what was the days in milk of these cows at the start of the trial?
They were all post-peak, mid-lactation cows. They were about 150 days in milk.
Okay, yeah. You know, and that greater increase with the palmitic versus the oleic in the low-fat cows does fit with some of the work we've done previously with production level and palmitic and oleic.
Because those low-fat cows had lower milk production than what the high-fat cows did, you could see that they were a bit lower on those diets.
So the lower producing cows, we would perhaps expect from our previous work to respond better to the high palmitic.
What was interesting here is that the oleic acid didn't show differences between the two overall, but when we look back at our data, these cows all started around 50 kilos.
That was kind of a range of previously we’ve seen that both of these treatments have a similar production response. I think if we had some very high producing cows, we would have seen a better response to the palmitic blend.
If we had lower producing cows, the oleic would have performed better. You know, maybe that's a case of hindsight on which cows we start with, but also we're always somewhat limited by which cows we have available when we do these studies.
And this was the group we had available. It was a very high group, a good producing group, and you know, both the supplements had a response.
Isn't there, you got, you know, there in that same article you mentioned earlier in Hoard's, they also made kind of—they didn't exactly say this, I'm paraphrasing—but they said, you know, milk yield is almost becoming meaningless; it's component yields.
I think that's not too far from the truth. So, you know, your components went up. I mean, there's statistically increased fat with both the basal treatment and the fatty acid treatment, and protein yield went up with the supplementation.
So what's your opinion on just not quite ignoring milk yield? Because it's still in there, but it's saying it's basically no big deal if milk goes up as long as component yield goes up.
I would totally agree. Probably 90-95% of all markets here in the US are paid for on the pounds of fat and protein.
The reality probably is if you could get more fat and protein and less fluid, the farmer would be better off from a shipping point of view.
You know, I think yield of fat, yield of protein, and then energy-corrected milk is kind of a way to capture the overall responses to those.
But no, I would agree. I'm also hearing more now, you know, a lot of people—I think Miner Institute was one of the first places I saw coin that 7-pound club to, you know, having your cows average pounds of fat and protein.
But now I'm hearing more people looking to push that to 8 pounds. You know, I just saw some data from Michigan recently because our feed manager wanted us to do somewhat better on this.
But there are some herds here, and I know elsewhere, well over 100-pound average with like 4.4 milk fat, you know, 3.2 protein.
As Mike Van Amberg and I were talking about that recently, and you know, as you said, Bill, it's the genetics and the nutrition, and we certainly couldn't be doing this with just one or the other.
But that speed of those generation intervals with that genetic selection and that increase in focus on the components is certainly a huge driver.
And probably to some extent, as nutritionists, we need to keep up with that advancement in some respects.
Now, you guys had kind of mentioned that earlier on. Is that changing the amount of fat that a cow can actually adapt to or assimilate, do you think?
Well, that's a good question. I kind of tongue-in-cheek say sometimes the highest fat diet a dairy cow probably ever sees is one that you throw out under fresh lush pasture. You know, they can be pretty high-fat diets.
I would say in general, we feed probably too lower fatty acid-based diets. A lot of it, as Clay sort of said earlier, is a kind of a hold-up still now from the last 20 years where we were struggling with milk fat depression a lot.
You know, when I first moved over here, over 20 years ago now, 3.5-3.6 was a pretty good milk fat. One of the only ways we could maybe manage it at that time was to come back on dietary fat, especially on available fat in the rumen.
But now we're getting a much better understanding, as Bill just said, feeding a 31% starch high moisture corn diet and still getting good milk fat.
I think we can start to push that more, and probably more and more from the basal diet, right? Not just from a supplemental fat source.
You know, we have access now to oilseeds that could help supply more basal fat in the diet or other sources that I think we can take more utilized more in the future.
But, you know, with these higher production and higher component yields, Scott, we need to be able to supply the building blocks and the nutrients that she needs to make all of that, right?
Yeah, so absolutely! And I'm wondering, do we ever hit a wall? Right? These cows are not slowing down; they're accelerating in terms of what genomics has done and what they can do. How far can we go?
Well, I always refer to a quote Dr. Balman made for a talk a number of years ago now, where basically I think the highest producers of today are going to be the average producers of the future.
So, you know, we know the sheer volume of or yield of components some of these record holders can make or these very high herds can make, and you know, we're probably going to continue going that way, right?
Now we are also doing it much faster than before as well, right? You know, I don't think there's no sign of slowing down right now for sure.
Yeah, Adam, can you remind our listeners what's the relationship between fatty acid level in the diet and crude fat or ether extract?
Well, I would—my recommendation is that we stop talking about ether extract. The most recent N that Dr. Weiss was involved in really promoted using the term measuring fatty acids.
That relationship across a typical diet, I would normally take off at least one unit of ether extract for fatty acids. Now, within individual feed ingredients, that is very different.
If I look at cottonseed, distillers grains, they're almost equal. But when you start looking at the forages, particularly the greener forages, ether extract is basically anything that's soluble in ether, and those forages and grasses contain a lot of chlorophyll-type pigments that are soluble in ether.
So that could be some of those only maybe 50% of that ether extract would be the fatty acids. I was like Jim Dr. used the term that the nutritional currency of fat is the fatty acids.
So, I don't even—I sometimes get asked to report ether extract on our papers, and I was like, no, you know, it's the fatty acids that we have to focus on.
And, you know, I think all commercial labs have ways of doing that now, and the nutrition models that I'm aware of all have fatty acids in. Lontano has a really good chapter on that in the recent N.
So, a basal diet where you're not adding any supplemental fat or oilseeds, I would say is 2% fatty acids pretty typical.
Yeah, two to two and a half, maybe up to 3%. You know, there is going to be some variability in the fat content of your forages.
There are some studies showing that, interestingly, that's the one value we often just use book values for feeds. So, you know, I think it's important that we get some measures there.
But I think that would be, you know, maybe three to 4% ether extract. Some of these byproducts can be really—distillers there can be high. Some corn grains can be 5% fat.
So, it's a lot—we say it's not that variable, but when you look at it as a proportion of the mean, it's actually a lot more variable than people think.
And I think across all of those feeds, the total fatty acid content of those feeds is going to be more variable than the actual fatty acid profile.
Oh yeah, especially forages.
Yeah, the forages, the profile isn't going to change hugely within a forage type, but the content could change more than that.
EXA, and I think we'd even see that in some of our oilseeds and other products with cottonseed. This is something we've been talking with Kevin Hartine and others with lately.
The challenge with cottonseed is sometimes getting an accurate representative sample for wet chemistry of it, so you can see some variability there.
And there's probably some methodology improvements there we could probably get into. It's a feed you hate to have to analyze; you just hate it for anything fat or anything.
So, I want to talk a little bit about energy. You got feed efficiency increase with the high-fat diets. Do you think this is just the fat, you know, more gross energy, or do you think it's in digestibility, metabolizability, or is it just a gross energy thing?
Well, I think the answer is probably yes to both—all of that. But feed efficiency, or milk-to-feed ratio, as some of my colleagues here like to call it, which is actually the better way to say that.
With palmitic, obviously compared to the control diet, we're feeding a more energy-dense treatment. Some people have said to me before, "Why do your diets have to be isoenergetic or isolipid?"
Probably every time we submit a paper, we get that. But as some of our studies here show, I think it's important that you have a non-supplemental fat control because the argument then would be if we had a control that had the same fat level as well, which fatty acids would we use now?
You could pick and choose that almost to see which way your treatments went. So both those treatments, the palmitic and oleic ones, are more energy-dense compared to the control within the set.
Those two have similar energy, so that's part of it. But we also now know that some of those specific fatty acids have specific effects.
So, palmitic acid is a good example. We consistently see improvements in NDF digestibility, and we think it's rumen digestibility.
Actually, Jeff Bins had a nice discussion in his recent ISRP paper around how maybe palmitic acid may help improve fiber digestibility.
And then with the oleic acid, we've shown that it improves fatty acid absorption. Andreas Contreras is looking at this a lot more now and has some effects on adipose tissue metabolism and insulin sensitivity.
So I think part of it is we're simply just giving them a bit more energy, but also it's more biological effects of those individual fatty acids.
So, you know, for example, when we fed palmitic acid in early lactation cows a while ago, I think a nutrition model predicted like, let's say we got one extra Mcal from the diet.
But when we actually did gross digestible energy, it was like three, three and a half because of improvements in fiber digestibility and different aspects like that.
So I have a more philosophical question on feed efficiency. Should, you know, most people, it's kilos of either fat-corrected or energy-corrected milk per kilo DMI. Should we do milk energy rather than kilos?
You'd say this fat has so much energy, the protein has so much energy, the lactose has so much energy, and say total milk energy divided by feed. Is that a better way?
Because I've always said the energy-corrected milk equation doesn't work as well as people think on equalizing energy.
Yeah, and it also depends on what milk energy values you're using in that model. I know Lontano would always ask that you put the actual equation there so you know what your actual values for milk energy were.
So I think there's no single one ideal way of measuring feed efficiency, I don't think. And I think there's a whole range here.
I think the challenge with basic, let's say milk energy over dietary energy, is unless you're doing digestibility and digestible energy, we're guessing at a number for the feed side of it there.
And then the other aspect is my colleagues here are looking at if you're truly looking at feed efficiency, we should perhaps factor in body weight changes as well.
So, you know, I don't think there's one single way of doing that. I think energy-corrected milk over feed intake is a milk-to-feed ratio is pretty good.
As long as readers of the papers know what that is and the limitations of it, I think that's still a valid thing to look at.
But as Scott said earlier on, you know, maybe in the future we're going to do that based on pounds of fat and protein.
I guess my last question I usually ask is, you know, no experiment is perfect, no matter how many you've run. So what would you change if you could go back, knowing what you know now? What would you change about this experiment?
Yes, well, I perhaps would have, based on what we've done more recently with oilseeds, I would have maybe pushed that basal fat level a bit more.
In an ideal world, I would have had cows that were higher production and lower production. We did that in a different study as well.
I think that basal fat level would probably be the main part of it. I'm comfortable with the days; we had 21-day periods. I think that's pretty good.
You know, if the focus had been on body weight changes, longer periods might have been better.
There's a saying in—I think it's more of a British saying—but horses for courses, right? Depending on what your primary interests are, it really sets up how you do the study.
Do you think this brings another—if you use cottonseed, I really like how you balance hulls and meal to the cottonseed.
Let's say if you did distillers or soybeans, do you think you'd have gotten similar results?
There's a lot of factors in that one. Distillers, my analogy with distillers, I think is I could feed the same level of added fat from cottonseed or from distillers grains.
But I think the cottonseed was—we would have had a much greater risk of those lower milk fats of that high moisture, high starch diet just because of that speed that the fatty acids are available in the rumen.
You know, the benefit of cottonseed there is the cow actually has to break that seed, and then there's that slow release there.
So I think we would have probably seen a lot more interactions if we had distillers. But I think we would have had some milk fat depression issues with that at the levels that we were adding.
Now, of course, I know distillers has become probably much less variable than it was a number of years ago.
But you have to have a good handle on what the fat content of it is, and you know, you have to be watching that fermentability of the diet a lot more now with beans.
If we had done conventional soybeans as opposed to here, I think again we probably would have been at higher risk because we would have used roasted and ground beans.
And that again would be much more, I think, more rapidly available in the rumen than the cottonseed.
What I would like to do if I was doing this study right today—if someone wanted to help support this study today—I would do something like this with higher oleic soybeans.
There's a growing interest in many parts of the country here, especially in the Midwest and Northeast. As you know, we've done quite a few studies with them now, but that's lower risk compared to conventional soybeans because they're about 80% oleic as opposed to mostly linoleic.
As we're showing here in this paper, there's probably some good benefits specifically to oleic, but how these treatments, these fat supplements would interact with those higher oleic beans would be interesting.
Because on the one hand, maybe they could replace fat supplements to some extent, certain fat supplements of certain fatty acid profiles.
But you may also get an additive effect of having both in the diet, and then we might start talking about much higher fat diets.
But yeah, that would be what I'd like to do going forward with some of this.
I guess a take-home would be that listeners should be careful in extrapolating these results to other basal fat sources.
I think that's a great way of saying it, yes. Cottonseed is a much slower release of those fatty acids.
Yeah, I think that's a great way of concluding on that one.
So, kind of a follow-up to that, Bill. So, you know, what are some further practical implications of this research, Adam?
Well, I think one take-home is we shouldn't be afraid of feeding high-fat diets, you know, whether that's coming from basal or supplemental or both.
I think these cows, especially these high-producing cows, can handle those high-fat contents of the diet.
As Bill just said, be aware of where those fatty acids are coming from, right? We often hear that debate around is it nutrients or is it ingredients that are the most important?
I think I asked Dr. Weiss that question at Trait last year, and we both said yes, that you know, they're both important, right?
And that cottonseed versus distillers is a good example of that. We could provide the same nutrients, but how those ingredients feed out could be very different.
I think some other take-homes here are that, you know, we're continually showing some benefits of those higher palmitic and oleic blends to these higher producing cows.
And, you know, I think that's probably the main take-home. There are a lot of opportunities going forward.
I think, you know, any study like this is one small step in trying to better understand some of this, right? You know, all of these different studies are incremental little steps.
The one thing that's probably not as practical in this paper as in some of our others with this same study design is here it's a plus and a minus from a pure research point of view.
Comparing cottonseed versus cottonseed hulls and cottonseed meal really pinpoints just that it was the fatty acid effect, whereas in reality here, maybe we might look at cottonseed versus soy hulls, okay?
And I think you can extrapolate what you see here to that same scenario.
Adam, I'm curious, you know, with your sort of your take-home there, what do you consider a high-fat diet?
Well, I would be up over five, I think, you know, six, 6% fatty acids. Yeah, we could—I think we can easily go at that level.
The couple of dose response studies we just published in the Journal of Dairy Science, we went up to 24% whole cottonseed.
Now, we dropped some intake at that high level, and we did the same with higher oleic soybeans. So we can get some very high-fat diets. You're going to see some drop-offs in digestibility, so there's some give and take in some of that.
But one take-home from this discussion here to me as well is that we shouldn't be—that we sometimes maybe feed too lower fat diets for these high-producing cows.
Yeah, just take that just a step further, Adam. I was just kind of curious, so is most of that from—you mentioned digestibility. So is that from a rumen digestibility or a biological maximum of how much a cow can really use?
From a fatty acid standpoint, that's going to be limited reductions in absorption in the small intestine. All these long-chain fatty acids are being absorbed in the small intestine.
The limitation at that point, I think, is emulsification capacity. You know, and that's why, for example, if I fed the same similar level of cottonseed, that's bringing some more unsaturated fatty acids versus another source that may come more straight with saturated fatty acids in a supplement.
Even though most of that linoleic in the cottonseed is going to get biohydrogenated to stearic, some of those unsaturates are getting through.
We've shown, for example, even 20 grams of oleic acid is additional into the small intestine. We can see a five, six percentage unit improvement in absorption.
So that's where another added advantage potential is some of these oilseeds. You know, if you feed a high-fat diet, we want to try and maintain some of that level of absorption.
You know, the goal is we get more of these nutrients into the cow itself, right?
All right, Bill, anything else for us?
One last thing. When I was in graduate school, which was a million years ago, Don Palmquist was one of my professors, and he said—and he said this for years and years—a cow can be fed as much fat as she puts out in milk.
He just said that forever, and I just did a calculation that with this data, that's about 6.5% fatty acids. So, you know, he might be right even at these very, very high levels, much higher than when he was making these statements.
Yeah, I still hear that one a lot, and of course, Don was the leader of pushing this whole fatty acid digestion metabolism in dairy cows for a long, long time there at Ohio State with yourself.
The one interesting thing—and this is something we're getting more interested in now—is we shouldn't just focus in on the fatty acid side in the diet on how she makes milk fat.
This is probably a bigger take-home as well. A lot of those fatty acids in milk are coming from acetate in the rumen, predominantly acetate.
So, I think those farms now that are most successful having those high production and high component milk fat probably are the ones that probably have the best forages as well.
So let's not just—we don't want to just focus on one side of that. You know, these dietary fatty acids are only contributing to 16 carbons and higher in milk.
It's the acetate and butyrate that's contributing that short and medium chain fatty acid. So the mammary gland can make milk fat in multiple different ways; she's very flexible in doing that.
But if we—so we need to think going forward is how do we supply precursors for both sides of that, you know, higher basal fat diets, but can we maybe get more acetate being produced in the rumen?
Is that through better quality forages or other ways that we can get some of that there?
Adam, kind of an off-the-wall kind of a question. You mentioned before that maybe one of the limits was intestinal digestibility due to not enough emulsifiers.
Have we looked at supplementing emulsifiers?
That's a good question. We've done some oleic acid works as an emulsifier. We've also got a couple of studies published where we looked at some polysorbates, some different types of polysorbates as emulsifiers.
Of course, the cow's natural way of doing it is liver lipase coming from pancreatic juices in the liver.
I would be interested in doing some work with some exogenous liver lipase. We've looked at lipase itself; we haven't published this yet, but we didn't see any improvements.
So maybe it is really the liver lipase that's important there. But I think there are ways we can do it that way. Oleic acid, I think, could be important there, and probably some of the polyunsaturates could all help absorption in some of that ways.
But AIC acid is certainly one. And that's again where those oilseeds, I think, have some benefits over like stearic-rich supplemental fats because they both deliver stearic ultimately after biohydrogenation.
But with the oilseeds, we're getting some more of those unsaturates come through as well.
I have to tell you about a herd I came across last week in my travels. This herd's averaging—they're averaging in the high 90s for milk. It's a Holstein herd; they're running a 5.1 fat and a 3.6 protein.
Good God! I'd like to see that diet!
You sure they're black and white and not brown?
They are! It's incredible! I know the nutritionists very well, but I haven't seen the diet.
My only concern with some of those type records is how often is that DHI testing? Is it on a single milking a day or is it on all the milkings?
I know they have equations to—no, this is on what they're shipping. These are bulk tanks.
Oh, shipping! Oh, I see!
Oh wow!
Yeah, the one thing I've heard Dave Barbano and Mike Van Amberg talk a little about is that from a cheese production standpoint, are we starting to get out some of the ratios for the best full producers that can't skim their fat off?
You know, a lot of the big ones are going to take the fat off anyway and use it, right?
So, yeah, I'd like to see that diet, Clay. That sounds interesting.
As far as your fat feeding recommendations, how would it differ in a fresh cow?
My personal recommendations, I'd be going with that palmitic and oleic blend, like a 6030 blend that we used here.
We had—there's that Jonas, I think it's 2021, a couple of papers there showing that we got a better—we got a similar production response compared to the oleic, but we didn't—those cows, even though they were like four kilos more milk, they didn't lose any more body weight than the control cows.
So I think we get the benefits of both sides of that there, and you can do that from blending two commercial products, or there are some commercial products out there now that can do that.
We can talk more about that sometime if you want.
That old Palmquist recommendation you brought up, I used to hear that all the time.
That is—that's an interesting thought with some of what some of these CS are putting out right now.
I would like to go back, and a number of years ago now, we did a dose response with a palmitic pill, and we got up to like 2.5% with it, but we did lose digestibility.
But we know a lot more about how we could avoid that now. But we're doing some work right now where we're feeding higher levels of higher oleic soybeans with and without palmitic acid in the diet.
So we'd be maybe getting up to, you know, 5-5.5% fatty acids.
SATs come through as well.
Yeah, makes sense!
All right, gentlemen, if that's it, I think the ladies did flicker the lights. That means it is last call.
And with that, what I'd like to do is—and Adam, you've already given us some good take-home messages—but I'd like to give the others as well another bite at the apple to give us kind of their take-home messages or what are some of the key things that the audience ought to take from this discussion.
And Clay, if you don't mind, would you start us off?
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Yeah, I mean, I think we hit on a lot of this already. Really great discussion there.
So, yeah, I would reiterate what Adam was saying there, that we should take a fresh look at how much fat we're feeding these cows on a basal diet.
And certainly, the sources make a big difference here. And yeah, I really enjoyed this conversation. A lot of good points in this study.
All right, thanks, CL!
Bill, great paper! You outdid yourself once again. Great guest! Anything you'd like to add to that?
Yeah, it's just repeating what Clay and Adam said. We have to look at total diets, not just supplementation. I think cows can be fed a lot more fat than what historically was considered excess.
And lastly, I really liked what I really liked about this study, even though on practicality it's not that important, but for scientific it is.
And that's the use of—he basically made whole cottonseed without fat, and that just makes the interpretation so much cleaner that you've isolated it as a fat.
I really like that in this. It's hard to do in some studies, so I really think that's a good way to do this if you can do it.
Yeah, appreciate that!
Adam, any final words?
I think we've touched on all of them. I guess my final word here, I think, is—as Clay said, you know, we can be looking at—we can feed higher fat diets, I think.
But the fatty acid profile of any and all of those ingredients that we might be using is going to be key, okay?
And again, what we just talked about, the fatty acid side of it is one side of the milk fat synthesis equation. So we need to keep both sides of that in check.
Kevin Hartine and others, and we've done in one study, have been looking at the de novo side of it as well.
Bringing those together is maybe how we can keep up with that genetic improvement and drive more milk fat yield.
Yeah, good!
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