How Dietary Fat and Supplements Impact Melting Properties of Milk Fat

- Okay, I'd like to welcome you today to our "Value Added Dairy Foods" webinar series.

We're excited to have Dr. ‪Kevin Harvatine as our presenter.

He is a professor of nutritional physiology in the Department of Animal Science at Penn State.

And he'll be talking to us today about "Fat Supplements and How Dietary Farm Impacts "Melting Properties of Milk Fat".

Quite a title, he may have changed that a little bit, but that's what I copied from another presentation that he gave recently.

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I'm gonna welcome Dr. Harvatine for joining us, to join us today.

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- Thank you for having me.

Okay. Hopefully you can see my slides now. Great.

So really excited to talk about this.

And I guess I should first kind of, you got the disclaimer that we are not giving vet advice here.

And the other disclaimer should be that I'm a dairy nutritionist and do lactation work and I'm not a dairy foods processing person.

But that's where this project's kind of neat because we're trying to bridge that gap.

So if you think about the dairy industry, we have, I'm gonna call it a problem, that we are very much a commodity industry and we have different segments that don't talk very much to each other and don't really interact or coordinate very well.

So on the side that I work on, on the production side, we're focusing on producing milk and we are watching our amount of fat and protein in that milk because we're getting paid for that.

We're watching what we call milk quality as far as somatic cell and bacteria counts, and we are getting some premiums for that.

But then beyond that, we really don't have much of an understanding on what impacts that milk that provides value to the processor or to the consumer beyond just the amount of fat and protein that we're providing.

So on the processing side, milk is not all the same.

And there there's a lot of things that we probably can impact on the production side that could add value to that product.

So what I wanna talk to you about today is milk fat and what we do on farms that changes milk fat as a profile.

And then some of the new characterization we've done of that resulting milk fat that shows that there are some changes in those physical properties of that milk fat that may have an impact for the consumer.

Wanna recognize that they have a number of students working in this area.

Alanna Staffin is a student that's did quite a bit of work over the last six months, and I'm gonna be using quite a few of her slides to tell you about our newest data.

So I wanna start out talking about what is milk fat?

So we have to first recognize we have a sort of a unique situation that oil and water do not mix, but milk fat does homogenize and does stay in solution, right.

So why is that?

Well, that droplet of milk fat is actually surrounded by phospholipids and proteins, and we call that the milk fat globular membrane.

Really unique, biologically very important in how the cow is secreting that milk fat.

And it also has implications all the way through processing and even possibly human health as far as that milk fat globular membrane actually interacting during digestion absorption.

We're not gonna talk too much about that, but I want to bring that up that there's a lot of unique aspects about milk fat.

When we look at the fat in milk fat, it's mostly triglycerides.

So to take you back to your chemistry days, that triglyceride is a glycerol with three fatty acids attached to it.

And that's usually how plants or oil seeds store fatty acids.

It's how we store fatty acids in our body.

It's how cows store fatty acids in milk.

So they're in that triglyceride.

And where do those fatty acids come from that are put in milk fat?

When we talk about milk fat, we usually talk about three different sources.

We have de novo fatty acids, and de novo means made new.

So these are the fatty acids that the cow is making in the mammary gland.

And they are 16 carbons, or sorry, they're all less than 16 carbons.

So we have starting from four carbons up to 14 carbons, they are 100% made in the mammary gland.

The 16 carbon fatty acids we call a mixed source because about half of those are coming from synthesis in the mammary gland and half of those are coming from uptake from the blood.

And then all of the fatty acids that are 18 carbons or longer, are coming from the blood.

And we have to step back and say, well, where are they coming from in the blood?

Like, where's the blood getting 'em?

Well, 85% of those are coming from the diet, the rest are coming from recycling from other tissues, from storage that we say are coming off of her back.

So if we start thinking about how do we change milk fatty acid profile, if we change the amount of fat that we feed that cow or the profile of that fat that we feed the cow, we can have a big impact not just on the amount of preformed, but definitely on the profile of those preformed fatty acids.

On the de novo side we can have an impact there basically on how much milk fat that cow is able to make in her mammary gland.

We'll talk a little bit, couple details of that coming up.

I wanna mention just a little bit on the chemistry of fatty acids.

So we talk about fatty acids, we talk about the number of carbons, so that's the chain length of the fatty acid.

The number of double bonds, so that could be a saturated fat that is no double bonds.

We have mono and a few polyunsaturated fats in milk, but we really don't have many polyunsaturated fatty acids.

And then the last is the location in the orientation of those double bonds.

The big thing for our melting temperature discussion is gonna be a cis double bond versus a trans double bond.

Very big difference in melting temperature.

So at room temp a trans bond fatty acid is solid versus a cis is going to be liquid.

And just to kind of show what this looks like, we have fatty acids on the left that differ in the number of carbons, that chain length.

We have in the middle fatty acids that are unsaturated, they have those double bonds, but they have 'em in different places.

And then we have that cis versus trans configuration.

And that's a big effect on the melting temperature for that cis versus trans.

The other thing that we have a big challenge in the cow is that the profile of the diet is not the profile that's absorbed by that cow.

And that's because we have the rumen in the middle with all those microbes that metabolize the fatty acids in the diet.

So I like this kind of quick simulation that Dr. Jenkins did a number of years ago, that if you look at in the diet that cow's consuming almost 900 grams of fat, very little saturated fat, so only two grams of stearic acid in this diet: mostly 18:1 and 18:2.

But now if we look at what happens after biohydrogenation, the rumen microbes have converted that unsaturated fat to mostly saturated fat.

It doesn't go to completion, you are going to get some trans fatty acids coming through the rumen.

But from the melting temp-ish side, this is a really big issue for us because we are taking these unsaturated fatty acids, again, liquid at room temp to be saturated fat.

And the rumen microbes are really good at doing this.

So that's the first thing is that we are saturating these unsaturated fatty acids.

The second thing is that if we go in and try to modify fatty acid profile of milk, we have the challenge that we need to get something through the rumen.

And we currently do not really have all that great of approaches to be able to protect fatty acids in the rumen.

Those microbes are pretty good at getting access and doing this metabolism.

So milk fat's really complex.

So there's a old review that summarizes this, that claims there's over 400 different fatty acids in milk and there are, there's a lot of, a lot of unique fatty acids.

We have a lot of different trans fatty acids from the rumen biohydrogenation process.

We also have a lot of microbially synthesized fatty acids.

The odd and branch chain fatty acids that are unique to milk, probably have some beneficial human health properties.

But a lot of those are in low concentrations.

If we look at really 17 fatty acids will make up about 86% of the total fatty acids in milk.

And I have those summarized here showing the fatty acid, the melting temp of that fatty acid, and then the normal range in milk.

So I should mention also that milk is unique in having these short and medium chain fatty acids.

If we look at our plant oils, outside of coconut oil, we really don't have 14 carbon in shorter fatty acids.

So if we look at all of our, you know, soybean, corn, canola, all of those normal plants are going to have 16 carbon and longer.

We have these shortened medium chain fatty acids that are synthesized in the mammary gland and are very unique to milk.

Even when adipose tissue fat cells synthesize fatty acids, they synthesize 16 carbon.

They don't really make these short and medium chain fatty acids.

So that's one unique thing.

And if we look at the melting temp of those short chain fatty acids, they're actually quite low.

So if we look at what's impacting melting temperatures, we increase chain length, we increase melting temperature, and then if we go up and we look at stearic acid at 70 degrees C versus oleic acid at 16 degrees C in 18:2 and 18:3 at minus -5 and -10, you see that we increase cis double bonds, we decrease that melting temperature.

So it's really important for us to keep in mind that as we want to change melting temperature of milk fat, we have a couple opportunities; we can increase those short and medium chain fatty acids and that's going to decrease our melting temp, we can increase cis double bonds and we can decrease melting temp that way.

If we increase the saturated long chains, we're going to increase melting temperature, okay.

So now that's on the melting temp side.

If we look at the concentration in milk, these short and medium chain fatty acids, I'm gonna call these moderate levels, right, they're not trace amounts, but they're not huge, huge levels.

We start getting up to 14:0 and especially 16:0, we have a lot of 16:0.

And I'm not sure why that's jumping on me, but we have, you know, just gonna call this 22 to 35% palmitic acid in milk fat.

9 to 14% stearic acid.

So those are two very high melting temp fatty acids that are making up, you know, 30, 40 some percent of our total fatty acids.

Trans fatty acids, there's a big range there, if your cows are milk fat depressed, they're gonna be on the high end of these trans levels.

And then let's look at oleic acid, 20 to 30%.

So very large amount of oleic acid and its melting temperature is quite a bit lower than palmitic and stearic acid, which were our other major fatty acids, right.

So if we think about this combination of how much of it's there and how different is its melting temperature, we'd quite quickly be looking at, that if we add up all these short and medium chain fatty acids, that's gonna have an impact that they're quite low in melting temp.

Palmitic and stearic acid are a large part of our fat and they're high melting temp.

Oleic acid, big contributor and it's a lower melting temp.

So those are fatty acids for us to keep in mind.

How variable are these?

Well they're reasonably variable, you know, milk fat kind of has its limitations that we can't take these to zero and they're not gonna be 99% of the fatty acids, there is some limits to the biology.

But there's also some reasonable variation in the concentration that we see.

So this is, the fatty acid profile reported in the literature.

And I'll say, you know, these are gonna be more extreme than what you'll see on normal farms in the U.S.

because sometimes nutritionists do crazy experiments, you know, using, not real-world type diets or things like that just to test boundaries, right.

So if we look at some of these shorter chain, short and medium chain fatty acids, you know, you're 8, 10 on the lower side, over 20% on the high side.

Palmitic acid, you know, 18, 20% on the lower side, almost 40% on the higher side.

18.0.

18.0, same thing, 4% up to 18%.

This is gonna depend on how much of that you're feeding. how much fat in the diet.

And oleic acid, big range there also, 14 to 28%.

So again, we're not going 0 to 100%, but we have some pretty significant ranges here that we can modify through nutrition management type opportunities.

So as a nutritionist, we can think about where we're getting these fatty acids?

Well those de novo synthesized fatty acids, those short and medium chain are coming from acetate and beta-hydroxybutyrate that are VFAs are made by the microbes in the rumen.

So we can decrease this if we get diet-induced milk fat depression.

We can also decrease these by not having good rumen fermentation in general.

Saturated fatty acids, they're absorbed.

Again, these are coming from unsaturated fat in the diet that's biohydrogenated, but also feeding saturated fatty acids.

Some of these are put straight into milk and they're gonna be saturated fats and milk, but the mammary gland also has an enzyme that we call a desaturase enzyme that can convert that saturated fatty acid to a monounsaturated and that's going to be a big decrease in melting temperature, right.

Microbial-derived fatty acids.

Those trans fatty acids odd and branch chain fatty acids are just gonna be put right into milk, and same that trans and unsaturated, if they get absorbed will be transferred into milk and we'll show that, we'll see them show up in milk.

Again, our challenge with unsaturated fatty acids is getting them through the rumen.

So why do we feed fat to cows?

Number of reasons.

The first would be to increase diet energy density.

We have high producing cows, we wanna support that milk production, we need to get energy intake.

We also want those cows regaining body weight so they rebreed, and in increasing energy density diet's gonna help with that.

So why do we do this by feeding fat rather than additional grain?

Well, by feeding that fat, we're not taking the risk of ruminal acidosis in rumen upset.

So it's really an opportunity to get some extra intake or some extra energy intake without risking acidosis.

It is not cheap, especially now our fat market has gone up in price from mostly competition with renewable fuels.

We also feed fats that support or increase milk fat yield palmitic acids, the most consistent in doing that.

And some specialty fat supplements are fed to provide essential fatty acids.

So where is this fat coming from?

I like to look at feeding fat as different levels depending on how much fat you're feeding.

So all of our feeds that we are going to feed the cow are going to have a little bit of fat in them.

So that corn silage, that alfalfa corn grain, you know, it's gonna be 1 to 3% fat, so quite low in concentration, but the cows are eating a lot of it.

So that's actually quite a few grams of fat coming into the diet that way.

When we want to increase dietary fat above those basal levels, we usually start feeding what I call rumen available in economical fat.

So a good example of that would be oil seeds.

So we'd have things like cotton seed or whole soybeans.

We have to be careful because that unsaturated fat from those sources do put us at risk for milk fat depression.

And then if we're going to try to increase dietary fat above the levels that we can feed there, we're going to start feeding what we call rumen inert fats.

So some of these are gonna be highly saturated fats that the rumen, that don't disturb rumen microbes.

There'd be other fats that we bind to a calcium salt and then that slow release in the rumen and makes them have less of a negative impact on rumen fermentation.

So I would, we do need to point out that, you know, all cows have a very low fat diet compared to us.

You know, they're not going to Burger King and getting 30% fat, but they're, you know, we can see pretty significant differences in the cow when we're going from 3, 4, 5% fat.

You know, I know my chart's going up to six, there'd be experimental diets going to that, but really in the real world we're probably topping out 5 1/2% percent or so fatty acids.

So I really need to mention on the producer side, you know, why are producers worried about fat and increasing milk fat?

Well, if you look at what farmers are being paid for, they're mostly being paid for fat and protein.

So this graph is showing the value of milk, the different milk components for an cow making 85 pounds of milk with a 3.9 fat, and a 3.1 protein.

Over the past five years, fat's averaged 2.44 pound; protein, 2.70 other solids 27 cents.

So farmers are being paid for the fat and protein that they're producing and very little for that lactose in the water.

So this has put a lot of interest and a lot of focus on increasing milk fat yield.

So how do we do that?

Well, I like to look at this as nutritional factors and non nutritional factors.

So let's start with non nutritional factors.

So there's affected genetics, highly heritable trait.

There's effective season, we have highest milk fat in January, lowest in July.

Effective stage lactation parody, those things we don't have a lot of influence in the short term, right.

Longer term we are breeding cows for higher milk fat, but in the short term we usually use these to set our goals or our expectation on that farm.

On the nutrition side, we can reduce milk fat by what we call classic diet induced milk fat depression.

I already mentioned this a couple times without explaining it very well, but what happens with milk fat depression is that you disturb rumen fermentation and you shift the microbial population in the rumen and the microbial population that you have produces some bioactive fatty acids that can reduce milk fat up to 50%.

So since farmers are being paid for milk fat, that is not a good deal, and farmers are trying to reduce the amount of milk fat depression that they have.

The challenges is that, what causes milk fat depression are dietary factors that increase energy intake and help help sustain high levels of milk production, right.

So when we feed, start feeding grain, that puts us at risk.

We start feeding additional fat that puts us at risk.

So our challenge is always kind of balancing the diet to maintain normal rumen fermentation, but at the same time balancing it so we have as much energy intake as we can.

So a lot of the work that's been done over the past three decades really has been focused on reducing that risk for milk fat depression and understanding what goes on there.

More recently, what we've spent some more time looking at is what we think of as the additional substrate for making milk fat.

So that cow is metabolically making fat if she's short on what she needs to make that fat, you can limit milk fat production.

So acetate is a VFA that she uses mainly to make those de novo fatty acids.

And we have quite a bit of work showing that if we increase the amount of acetate, we can increase milk fat a little bit.

There's also a good bit of work recently showing that if you feed additional fat, especially palmitic acid in a lot of conditions, in a number of places, you can increase milk fat, and we'll show some data on that.

So what's been happening at the farm level?

Are we managing to maximize milk fat?

Well, we certainly are.

This is the 12-month running average for milk fat in the Northeast milk market in blue and in Florida in the orange over the past 20, 23 years.

And you see since 2010, we've been on a linear increase in milk fat.

Our average milk fat now is pretty close to 4.1%.

This has been happening in every milk market, but Florida, and likely this is because the increase, a lot of this is being driven by genetic selection that we're selecting for cows with higher milk fat percent.

But we're also feeding cows and managing cows so that they can make higher milk fat.

Why is that not happening in Florida?

Well, they have some unique things about their diet and heat stress that make it a lot harder to do this.

So this really shows that we have a cow that can make more milk fat, but we have to manage her and feed her so that she can do that.

So just to quickly talk about this rumen metabolism issue and milk fat depression so that those rumen microbes are trying to convert that unsaturated fat to a saturated fat, and in that process they make some trans fatty acids.

Normally they're gonna make trans-11.

If you get that altered microbial fermentation that change that microbial population you end up with microbes that make trans-10 intermediates.

And some of those are bioactive and reduce milk fat.

An important implication for a discussion of melting temperature is that it doesn't decrease all fatty acids equally, it decreases those short and medium chain fatty acids more than the long chain fatty acids.

And we get an increase in these trans, total trans, and again, those are higher melting temp.

So that's talking about milk fat depression and we, again, want to manage to minimize the amount of milk fat depression that we have.

The other part of this is mentioned that if we feed fat, sometimes we can get additional milk fat.

And sometimes we don't get additional milk fat, but when we change dietary fat, we certainly change fatty acid profile of the milk.

So just wanted to kind of walk through this scenario a little bit.

So we have dietary fat concentration on our x-axis and quite quite often we can go from a low fat diet to a high fat diet and total milk fat will not change.

Sometimes it'll go up a little bit, but sometimes it won't change.

But when we look at fatty acid profile, what we see is that as we start feeding more fat, the amount of de novo fatty acids go down and the amount of preformed fatty acids go up.

So what's happening here, I at least like to talk about this as the mammary gland being lazy, that it's a lot of work and takes a lot of energy to make that fat from scratch.

If that mammary gland can take a fatty acid out of blood and use that, that's a lot easier.

So you get this swapping.

So in this case, as you feed more dietary fat, you generally expect to decrease de novo fatty acids.

And again, on the melting temp side, these de novo fatty acids are quite low melting temp, that preformed fatty acid now it depends what fatty acid that is, and this is where we need to think about that 16 carbon versus an 18 carbon fatty acid.

And we're gonna have some differential effects on milk fat.

The other thing is that sometimes when we feed lower fat diets, the cow simply cannot make up for that fat deficit that they run into a maximal level of de novo fatty acid synthesis and then that total milk fat starts dropping off.

And remember we said that producer's being paid for milk fat, they want to get as much milk fat as they can.

This is the scenario where we need to start supplementing more fat.

And that's the reason we are supplementing fat is that that cow cannot make up for that, she can't make it all on her own, okay.

So the fatty acid profile changes the effect that we see on milk fat if we feed unsaturated fat supplements, so this is what we'd be getting from cotton seed and soybeans.

Quite often we can feed a little bit of that with no issue, but we are taking the risk for diet-induced milk fat depression.

And that's why we have a limited on the amount of that that we can feed.

There's a nice meta-analysis, recent meta-analysis, that looked at what was the effect of increasing saturated fat supplements?

And we really have two choices in the industry; we can feed a combination of palmitic and stearic or we can feed a high palmitic.

So when we feed 16.0 and 18:0, for each one percentage unit increase in the diet, milk fat increased 23 grams per day, and milk preformed fatty acids increased 1% unit and the de novos decrease 1% unit.

When we increase palmitic acid, so for 1% unit increase in the diet, you got 67 grams per day.

So this is where you got almost threefold more milk fat.

These palmitic supplements are quite consistent in increasing the amount of milk fat.

And when they did that, the 16 carbon fatty acids increased 3.6% units and de novos decreased 1.8% units.

And this is gonna have an impact on that melting temp as we'll discuss coming up.

So in our commercial diets, I would say in the U.S. of 1% unit is a reasonable feeding rate of these supplements, experimentally we'll go to 2%, but that gives you an idea of the magnitude of the change.

So let's kind of switch and talk about the importance for dairy products.

And we're really gonna focus on butter here, and this is where I'm not the dairy foods person, but my understanding is that a big implication for this is the temperature that the consumer is experiencing the product.

And we'll show some of these melting curves coming up, but what's important is that a lot of our butter we're experiencing at room temperature, which is a more dynamic area for the melting properties of butter.

If you are eating soup that has milk fat in it, it's already warm.

If you're eating pizza, it's warm.

At those temperatures you're sort of more out of the dynamic range and there's not as much of a difference.

But with butter is where the consumer is going to have a bigger relationship with this.

So my understanding of how we should be thinking about butter is that really it's a combination of solid in liquid at all points.

So, you know, we see melted butter and it's 100% liquid.

You see butter that's in your refrigerator and it looks like a solid to you, but it's still a mixture of solid in liquid.

It's just that when it's in the refrigerator it's a lot more solid.

So then it is solid to us visually, right.

So if we can look at this as a percent solid as we go across temperatures and we can go to very cold where it's very hard, very solid.

We heat it and it's still to us visually a solid, but it's softer because a smaller percentage of that is solid and more of it is liquid.

And then we take that to fully melted and now it's all liquid.

But we really have to think about this as that combination and what percent solid fat is it and what percent liquid, and how can something be solid and liquid at the same time?

Well, you have a very heterogeneous mixture, so it's all milk fat, but remember that milk fat's triglycerides, and each of those triglycerides is different from the others.

So that triglyceride is three fatty acids and there's a possibility of each of those positions being one of 400 different fatty acids.

So if you think about how many different triglycerides we can make, it is a lot of different triglycerides.

So that's why we end up with this really dynamic nature is that, yes, it's all fat, it's all triglycerides, but they're all different triglycerides, and each triglyceride has its own melting temperature that's mostly dependent on the fatty acid that's there, and then also the position of that fatty acid within the triglyceride.

So it becomes pretty complex.

Okay, so we've seen this already that the melting temperature is lower for those short chain, higher for the long chain, and our unsaturated fatty acids decrease melting temperature.

So what kind of sparked us to look at this was the Buttergate controversy in 2021.

So this started with a tweet from a cookbook author in Canada, and here's the tweet.

"Something is up with our butter supply.

"I'm going to get to the bottom of it.

"Have you noticed that it's no longer soft "at room temperature? Watery? Rubbery?" And then this tweet went viral and people were questioning has butter properties have changed.

And then also this in what they came out of this is that people thought, "Well maybe cows that are fed palmitic acid," and this is a practice that had been increasing over the past, probably 15 years in Canada, maybe this palmitic acid was having an impact.

And then the other spinoff to this that we won't talk about very much is that palmitic acid that we feed to cows is a byproduct of palm oil manufacturing.

And there's a number of environmental concerns that some people have about palm oil manufacturing.

So that's also part of this viral news storm, was not just the physical properties of the butter, but also this concern that people did not realize that palm products were being fed to dairy cows.

So just to kind of show how this took off, you know, it went through the media cycle and hung there for a little while.

You probably remember some of these headlines.

So what was the dairy industry response?

Well, I would say generally it was defensive and I can appreciate that when people are attacked and feel like you're being attacked, that normal reaction is to be defensive.

But I'd like us to kind of think back on this and think what we can learn from this and look at it that these are our consumers and maybe that we should look at this as a consumer expressing a need or a desire that maybe we could be better at meeting.

So the dairy industry had said nothing had changed in the last year about feeding cows.

That's probably true, but over a dozen years we certainly were feeding a lot more palmitic acid.

Many claim no science to back this up.

And there were a couple papers out there, but I think this really comes from sort of our silos that our dairy foods people were not so familiar with the nutrition, and our nutrition people were not familiar with the dairy processing side.

Some processes in Canada did ask producers to stop feeding palmitic acid until they could figure this out.

And I'm not sure how far that really went.

I did publish a summary of what was known in the literature in the "Journal of Dairy Science" back in 2001.

And I'll point you there if you'd like to know kind of the data that we had and I gonna show just a little bit of that right now.

So one of these papers in 2000 looked at infusion of palmitic or stearic acid in cows and then looked at percent solid fat at different temperatures.

And you can see that at 24 degrees C you had quite a big increase.

So from 29% to 39% being solid at 24 degrees C.

That stearic acid did not have an effect.

So you might be wondering how is palmitic acid increasing so much versus stearic acid when actually stearic acid has a slightly higher melting temp than palmitic acid?

And we'll get to that answer coming up.

There's also some physical properties work in a newer paper 2016 looking at, here's hardness, and I'm not really familiar with these units.

And I think, that's part of our issue again, not as a dairy nutritionist not being familiar on the processing side, but some pretty big differences in the numbers between high palmitic versus low palmitic fed.

We can look at this peak melting temp is over two degrees difference.

Basically every one of our metrics of hardness and melting is being changed by palmitic acid.

So our current objective is to determine the effective diet in fat supplements on milk fat melting properties.

And we're doing this work in collaboration with Greg Ziegler and Kerry in the Department of Food Sciences.

So really to me, a neat collaboration that we have going on.

So most of the data I'm gonna show today is from this recent experiment where a student did a dose escalation study where we feed from zero to 750 grams per day of either palmitic or stearic acid.

And this is part of another project where we're looking at the mammary biology of this, but we want to also see what's this doing to milk fat.

If we look at the production data, the gray is the controls, the green is the palmitic, and then the orange is the stearic.

And you can see why do we feed these?

Well we get increased milk fat yield, 193 grams more milk fat when we fed the palmitic.

We did get a milk fat yield response in this study with the stearic also.

Look at 16 carbon and 18 carbon fatty acids in milk, they also increased as we do this.

But when we increase the palmitic, it's mostly an increase in palmitic acid in milk versus when we give stearic, it's an increase in stearic acid but also oleic acid, which the mammary gland makes from stearic acid through that desaturase enzyme.

So we did differential scanning calorimetry, which is basically a machine that's melting is heating the sample looking at how much energy it takes to heat that sample.

And you get these curves.

So the red curve, just jumping around on me, the red curve is our, as we're heating that sample and when you see a big dip is where there's a lot of fat melting right at that temperature.

So you can see here around 19 degrees that we have a lot of fat melting.

That is our high melting temp group of triglycerides.

We can also integrate and we can look at the amount of solid fat or amount of fat that's melted up to that 20 degree C point.

So to show this data, this is looking at percent solid at room temperature.

Our palmitic acid is increasing from 32 up over almost 35 degrees or 35%.

And Kerry is telling me that this is a really big difference in percent solid that would be noticeable to the consumer.

What's interesting, if you look at stearic acid in this experiment, we actually decreased the percent solid at this highest dose.

And this is because that even though we're giving stearic it's being converted into oleic, and that's reducing our melting temp.

We can also, and actually here's our numbers on that, so palmitic is increasing palmitic from 30 to almost 37%, but when we give stearic, we only get 2% unit increase in stearic, but we get this 3% percentage unit increase in oleic, and oleic is much lower melting temperature.

We can also, we've also looked at peak melting temp and our palmitic is increasing that peak melting temp, stearic is not.

We can look at endset, which is basically when it's fully melted and we're increasing that in our palmitic and not in our stearic also.

So what's going on here?

Well, palmitic and stearic acid are both being taken up by the mammary gland, but we have this desaturase enzyme that is really active for stearic acid, it's converting almost 60% of that stearic acid to oleic dropping melting temperature almost 50 degrees C in that area versus for palmitic acid that desaturase enzyme is not very active, it's only converting 5% to the unsaturated form.

So this is the difference in the biology is palmitic acid is not being desaturated, it's maintaining as that higher melting temp fat.

We've also done some other work, so this is looking at 2% of a high palmitic acid supplement.

We see similar increases in percent solid endset and peak milk in that experiment.

We've also looked at feeding increasing amounts of high oleic soybeans.

And when we do that we decrease percent solid at 20 degrees C.

And again, it's not that we're getting much oleic passed the rumen, but we're increasing, that stearic's being converted back to oleic.

So to wrap up our key takeaways.

Feeding practices will influence melting properties of butter.

Palmitic acid supplements increased percent solid at room temperature substantially, stearic decreased to a lesser extent.

These differences are likely noticeable because, likely noticeable, but really would need to do some consumer taste test type panel work to demonstrate that.

So consumers are expressing preferences for higher quality butter through purchasing.

And I think you could argue this in showing the graph for Irish butter on the right.

And to me this is our risk in the dairy industry is that, you know, we have a lot of Irish butter coming in, competing with our butter.

There's a number of attributes to that the consumer might like, it's a different color.

Taste may be a little bit different.

There's certainly some marketing to it.

But this is, you know, $350 million worth of butter that we are not selling from U.S, farms.

So we have the opportunity to modify butter melting properties through dietary strategies.

And what I would like to see as our long-term outcome is to be able to say, if consumers have a desire for certain melting temperature, that we can make that butter and hopefully they will pay us a premium for that product.

Need to recognize the lab members that do the hard work in the lab.

We also have greatly benefited from funding from USDA and Northeast SARE specifically in this project.

Some of these experiments are also primarily funded by USDA or industry partners and then we're using that milk fat to do this further characterization.

Thank you, and hopefully we have some time for questions.

- Thank you very much Dr. Harvatine. Very interesting.

I don't see any questions in the chat yet, but we'll give people a couple minutes or if you'd like to ask a question, just raise your hand and we can unmute you and you can ask a question as well.

There we go, there's a question in the Q&A.

It says, "How does the composition of margarine compare?" - Oh, that would be, maybe Kerry could help me with that one.

I've not looked at margarine in a long time.

Margarine would not have the short and medium chain fatty acids.

So it classically it was soybean oil that's been partially converted to saturated fat.

So my guess it's mostly palmitic, stearic and oleic.

Is that right Kerry?

- Yeah, it's gonna be a lot more of the longer chains, a combination of the saturates and unsaturates.

But the other thing about margarine is they mix oils and they'll kinda blend those solid fat content properties so that that melting profile where milk fat, Kevin, you showed that great slide of it being solid at refrigerator temperature then kind of semi-solid in the middle.

Margarine profile, they'll blend oil so that that's much more flat all the way across different temperatures, so you don't see that difference.

So you hold it at refrigerator temperature, you hold it at room temperature, you don't see a lot of melting and resolidification because they just kind of select and it's much more of a homogenous fatty acid profile.

But most of them are the longer chain 16, 18, getting into the 22s and 24s because of the vegetables with multiple levels of unsaturation.

- Yeah, and Kerry can correct me on this, but we might wanna say that really there's no perfect butter, right, that there would be a preferred butter for different types of applications.

So when you're buttering your toast in the morning and you don't want it all squished in, ruined, right, you have a certain ideal temperature.

But then someone who's manufacturing croissants may have a different preferred, but it's kind of to me a neat opportunity where maybe we could do a better job there.

- I will back you up on that Kevin.

There's a lot of different, if you look into the fats and oils industry, they can start to get really specific on different types of butters for pastries, for croissants, for puff pastry, for other baking applications, for the confectionary applications versus home applications.

So we do look at different spreadability and different characteristics depending upon the application.

- If there's no other questions, I'll throw a question out to Kerry.

So I guess I'm not in tune to this, but, you know, we hear a lot about artisan cheeses, but I don't really see artisan butter, and I guess maybe two questions there, how much is this going to impact the artisan cheeses?

And then is there opportunity maybe for artisan butter?

- The work that we're gonna do?

I don't know if it'll affect the cheeses very much.

It may affect some of the artisanal butters for the people that are feeding with a smaller herd where you're kind of, same with cheese, if you're using a smaller herd, you're obviously more affected by the properties of the herd.

If you're a larger processor where you're bringing in a lot of commingled milk, you don't see those changes.

We do see some, a reasonable amount of artisanal butter and they don't tend to work it on machines as much as the larger companies.

So they may be a little bit more affected.

If it gets a little softer, they're going to have more oiling off.

If it gets a little bit harder, they're not gonna have as much water droplet distribution.

So I could see seeing some impacts of that depending on how they're manufacturing.

Again, the larger companies, they're using such big machines, you're gonna get really good water droplet distribution during churning.

I will say it's interesting that you've got the Kerrygold butter up on your slide at the moment and in the, when I did the nutrition conference talk last year and we demonstrated the difference in spreadability, Kerrygold is the butter that I use that you can actually take and make a thin slice and you can take it and twist it and bend it without it breaking.

So if you just do this in your home kitchen Kerrygold, you can get in the grocery stores worldwide, just take a little slice of that and a little slice of U.S. butter and you'll see a really big difference in what we call plasticity and spreadability.

- Yeah, and just to mention a little bit more on this to recognize that like what we're characterizing here, I would call like the fundamental properties of the butter oil that's there.

My understanding is there are these implications of how people are processing that, that there may be opportunities where through a certain manufacturing you could alleviate or modify some of this effect.

But, but to me it seems like processors would like to know what we're doing on the dairy industry side, just so that they know how they can can best handle that product.

- Think so. Good.

I think we've got a good project going.

- [Harvatine] Yeah.

- I'm not seeing any other questions.

Thank you again.

And there were, well one of the comments is from Kerry, but I echo her comment in helping to bridge that gap between production and processing.

We appreciate your time today and sharing your research with us.

Thank you.

- Yeah, thank you for having me.