Tim's Take Episode 31 | Derek Brake | Does Animal Physiology Impact Feed Requirements? - Tim’s Take

Episode Transcript
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(00:00):
[♫]
(Tim Reinbott) Well, welcome to Tim's Take! And today we have the pleasure of having Dr. Derek
Brake over in the Division of Animal Science, and he's a Assistant Professor in Ruminant
Nutrition. (Dr. Derek Brake) Yes, sir. (Tim) And you and some of your colleagues just got a

(00:22):
nice NIFA grant. (Derek) We sure did! (Tim) And not only though is it the animal science folks,
you've got an engineer involved in this. (Derek) Yes. (Tim) So what the heck are engineers and,
uh... animal scientists doing together? (Derek) Yeah, I know. You need to find a good joke.
I mean, the real... the real joke's like, what happens when a nutritionist, a geneticist, and an
engineer all go into a bar? What happens, right? (Tim) Right. (Derek) Like I've figured out the

(00:43):
answer to that. I'm not a very good comedian. But, um... but you know, really the way we all ended up
together, what we're... what we're all trying to work towards is find more efficient cattle.
Come up with a way that really, um... improves efficiency through the entire supply chain, um...
both for beef... it can extrapolate to some other things. What we're trying to do is,
we're really trying to capture the ability to... to measure some things that are hard to measure,

(01:08):
but we know are what really drive ultimately the feed bill,... (Tim) Right. (Derek) ...or how much
we... how much different cattle need to eat. And so, um... functionally, what we're trying to do is
come up with a way to, in real time, uh... measure the surface area... surface area of individual
animals. (Tim) Not just weight? (Derek) No, not just weight. (Tim) Weight is easy. (Derek) Which

(01:29):
is what we do. Yeah, so... and in fact, the... what's exciting about this work is... is... is,
we know some of this stuff. The... the, you know, the... the energy requirements of individual
animals is really, really important to, uh... to determining wh... which animal needs more feed
or... or less feed to stay alive, or which animal needs more feed or less feed to grow, so it... it

(01:51):
drives our feed efficiency. Now, the... the folks who first figured this stuff out, this happened
hundred... hundred years ago or more that this was really getting figured out, and they understood
that this was really related to surface area. Now the problem, however, and what they recognized was
it's really, really hard to measure surface area 100 years ago. And so they kind of threw their

(02:14):
hands up in the air, and they say, "Well, you know what? Body weight, we could use that instead.
We know that it's not as good, and we know that there's kind of some... some flaws to doing that,
but we're willing to accept that." Because at the time, it's a heck of a lot easier to put
a cow on a scale than... than it is to do a lot of different things to measure surface area. And

(02:37):
nowadays with the various sensors that have been created, um... that integrate with computers every
day, um... that are really integral in what they call "robotic vision," um... it's... it's actually
quite easy to... to get what my engineering colleague calls, uh... "the surface area of

(02:57):
a three-dimensional, non-uniform, deformable object," which is what an engineer likes to
call a cow. Um... but what... what we're hoping to do is actually tie way back to... to all of
that initial discovery work that... that was done and recognized and... and quit, or maybe move away
from, or add some more information to come up with a much more accurate way of identifying individual

(03:24):
differences in efficiency, or ultimately, of... of feed requirements of individual animals as
they're moving through the supply chain, or as they exist in a farm. Um... and then,
you know, you can feed that information back to producers, and they can make management decisions,
try and optimize the value of those individuals, and then ultimately, you maybe make more efficient

(03:49):
cattle in the long run (and this is where the geneticist comes in) where we can feed that
information back. We can try and figure out some of these genetic mechanisms that correlate back
to some of the bioenergetic requirements and... and make improved mating decisions and move the
whole US herd in... in the right direction. (Tim) So if you have a... an efficient animal, they're
going to use less energy to... for... for... for maintenance, so you can put more of that

(04:13):
into milk production, to growth, and everything. And when we get our... our... our forage analysis,
or grain analysis, we have, what? Net energy, gain, maintenance, and lactation. (Derek) Yes,
sir. (Tim) And TDN. (Derek) Yep. You got it. (Tim) But you said that net energy,
maint... net energy/maintenance is the... is the big one? (Derek) Net energy/maintenance is what

(04:35):
we use in all of our current model. So you talk to a nutritionist like me, that's... that's the
value that we're going to take, and we're going to use that to predict what your... what your
intake is going to be when... when the forage quality isn't so low that... that the size of
the stomach is what literally limits how much they can eat. Um... so, we typically think that cattle

(04:56):
eat to a common energy end point. Typically we relate to... that to net energy available for
maintenance. The energy available. And also the body uses calories and other nutrients. Um...
they don't get used evenly for all processes. So essentially, every time a cow eats something,
the first piece of that is going to go first to stay alive. So... (Tim) Maintenance. (Derek) Like,

(05:19):
yeah... maintenance. And so, that's... that's where that comes from. And so, right off of the
top, that... that portion of the feed is going to be used to meet that requirement. And then,
what's left, well... they take that piece out of that bin, and then that's going to be used
for whatever it is we want them to do, right? (Tim) Grow... (Derek) Grow, support of pregnancy,

(05:39):
lactate... things that... things that we actually as cattle producers capture value off of. Right?
So... because those are the marketable products, right? Pounds of beef, pounds of calf per acre,
pounds of milk per cow. And, so... (Tim) So when we start seeing animals losing weight during the
winter, they're not even getting the maintenance, are they? (Derek) Yeah! Well, absolutely! In fact,

(06:00):
that's nested into a lot of beef production cycles. That's... and that's not always a
bad thing. So we talk a lot about, um... when we're managing cows out in a pasture setting,
um... we're really sensitive to looking at their body condition. (Tim) Mhm. (Derek) And the reason
why we talk about looking at their body condition is, it's not a bad thing if... if, you know,
we're coming off of summer grass... spring or fall grasses, and maybe she had a little bit extra...

(06:21):
was able to eat a little bit over maintenance energy requirements, she put on a little bit of
extra fat in body condition in there, and then what we asked her to do is, we get into this
time of the year maybe a little bit further into January/February, the grass goes into a dormant
state, the energy and protein value drop off, there's not as much out there for her to eat,
and then so what she's going to do is, she's going to... when she goes below maintenance,

(06:44):
she's going to access that... that energy that she stored up from earlier in the year
in a pretty highly efficient process (that's why it's so stinking hard to lose weight sometimes,
right?). You got to go to the gym... (Tim) I'm too... I'm too efficient! (Derek) Yeah! That's
the whole thing, right?! Yeah, we're all rewarded for being efficient. That's the stinkin'... that's
the problem, right? I mean, and... and so anyways, that's pretty efficient. So... so

(07:05):
we're okay with our cows losing body condition, um... to a point. If... if we... if they get too
thin on us then we'll run into some train wrecks when it comes time to breed them again. (Tim) Or
she's pregnant. Is that okay if she's losing a little weight? (Derek) Uh... to a point. That's
actually a good... that's a great... that's a very researchable question. I work with some
colleagues that are really interested in that. And so, um... there's probably some things that aren't

(07:29):
recognized, some influences of changing, um... nutrition later in pregnancy that will influence
the calf, perhaps for its lifetime. (Tim) Right. (Derek) And so, um... that's a great question.
However, under... you know, there's an awful lot of management practices where, currently, where
that's, um... not being considered whether they ought to or not. (Tim) Right. Or like you said,

(07:52):
even or coming back in to pregnancy, that's... to be bred back... (Derek) A lot... a lot of
things... yeah, when you're talking about... when you... you're talking about the cow,
um... a lot of it has to do with, uh... trajectories too. So sometimes it's not
all absolute amounts, but kind of whether you're moving in the right direction or
the wrong direction kind of deal. Because the body will kind of shut down, um... you know,

(08:16):
things like, if she's not getting enough groceries, and... and it's... and it's a
taxing process to achieve a subsequent pregnancy, make another calf... well, all of a sudden,
we might decide biologically (it's a subconscious thing), but... but there's biological mechanisms
that effectively influence so that we're going to prioritize using the limited amount of groceries

(08:40):
we have to support the calf that's on the ground, or making milk to support that calf, or staying
alive ourselves before we try and achieve another pregnancy. (Tim) Sure. (Derek) And so that's a...
that's certainly a thing. So sometimes it's just as important, even though they might be thin,
just getting them back into a place where they have a little bit of excess because that'll

(09:01):
trigger some things that'll help you basically end up with a better pregnancy rate, which is... which
is what you're after. (Tim) Sure... sure. Now you mentioned, we... we talked about net energy,
but TDN is kind of that gross measurement that we can compare, like you said earlier,
if we're looking at hay, you can compare hays. (Derek) Sure, yeah. So TD... TDN is,

(09:21):
uh... so total digestible nutrients is what that typically refers to. It's a unitless value. It's
actually percentages is what it's referred to. Um... you know, TDN, there was a big push,
um... you know, really in an Extension and Outreach effort in the mid, uh... 1900s. So
about 1940 to 1960 there was... there was between about the 40s and 60s there was a big push to try

(09:46):
and educate a bunch of producers that, "Hey, you ought to be looking at this because it plays,
you know, the energy content of different things, plays an awful big role in... in your feed costs."
Right? And differences in efficiency. And at the time, um... what was pushed was TDN. Um...
what we know now is the way TDN is calculated, it actually uses some... not to get too in the weeds,

(10:13):
there's... there's just some factors in there that it uses to kind of standardize some things that
aren't always the same thing, so they're variable. So TDN's kind of one of those things like 60% of
the time it's right all the time. And so, but that being said, typically when you work within
the same class of feed, um... it's... it still works. Right? So like if you do... I mean,

(10:35):
you can use TDN still to rank hays, right? (Tim) Like if I'm buying tall fescue hay, and you've got
68 and I've got some 62, that 68 is going to be better. (Derek) Yeah, exactly. And so if... and so
when we extrapolate that, I mean, now is... does that mean that it'd be on... does the nutritionist
still want the net energy for maintenance and energy for gain so I can predict your, you know,

(10:56):
what the cows are going to do off of it? Yeah, absolutely. I want to know things like that. But,
that difference, um... in TDN is probably also going to be the same difference, or very similar
difference, that you're going to see in net energy available for maintenance and energy available
for gain. As long as you're within that similar nutrient, right? Like... or that simal feed...

(11:18):
similar feed type. Where you get into trouble is if all of a sudden... well, I want to say,
"Well, okay. Should I be feeding this... this 62 fescue hay versus... (TDN hay) versus soybean hulls?"
Because now all of a sudden, it's a little bit apples and oranges when you get into some stuff
like that. And so that's where... (Tim) The high protein? (Derek) Yeah. And so what you can do is,

(11:41):
you can get into the... the way to make better decisions there is to start using one of your
net energy values when you want to do things like that because the body basically handles
excess protein differently. And so... (Tim) We pee it out, don't we? (Derek) Yeah! Well,
yeah! Exactly! Well, it's the keto diet, right? I mean, that's the whole thing is the,

(12:03):
um... and there's... there's actually a higher caloric cost when you overeat protein. That's
the whole concept behind the... the keto diet. Um... the... but, it... you also need protein.
So the closer you are to that protein requirement... well, there's a lesser energetic cost associated
with overeating protein. So... so that's where, not to get really complex, but that's... it's...

(12:26):
it really is like a sliding scale. And... and... and so when you move into different feed types,
it... that's where kind of TDN doesn't... isn't the best way to make... make your best feed
purchases when you get into some things like that. That's where net energy maintenance and
energy gain are better. (Tim) So people like me skip over those three, go right to that one easy
one. I mean, I do that a lot. (Derek) Yeah, you're not the only one. (Tim) So I need really need to

(12:50):
pay attention and compare those... those three that... that also get net energy gain, lactation
and maintenance. Uh... the other thing is, I've heard Extension agronomist say that energy is
the hardest thing to get in the winter time. It's the most expensive. Well, protein's easy. Energy
is harder. Is that... is that how animal scientist looks at it too? (Derek) Yeah, so... yeah. I mean,

(13:13):
energy is what drives the boat almost always. So, I mean, so... a lot of the times when we're
talking about cattle, energy or... energy is what drives all of the performance responses, all of
the feed intake requirements once the animal's achieved puberty. So, which is really close to
weaning typically. (Tim) 400 - 500 pounds? (Derek) Yeah, when you... yeah. So it's somewhere in that

(13:37):
4 to 600 pounds is pretty... pretty common for when we'd classify that. Before then, protein's a
lot higher of... a lot closer in importance to... to calories. But what happens is some of these
same guys, um... that did some of the work that kind of figured out this relationship of energy
requirements and surface area, well, some of them also defined things like puberty to a guy who's

(14:03):
talks in bioenergetics. One way to define puberty is actually the point at which that next pound of
gain, when there's a greater caloric amount of gain associated with adipose, or fat, than there
is with protein. And so that's what happens as the animal matures. So as they... as they get
more physiological mature, um... a greater amount of gain becomes fat. And so... (Tim) That's what

(14:27):
happens in the feedlot! (Derek) That happens in the feedlot. It actually happens a lot earlier
than in the feed lot, but... but... but because of that, that's why calories are so important.
Because fat, or adipose, has about 225% the amount of calories in it than carbohydrates or protein to
some extent. Um... probably closer to 200%... 180. But the, um... but anyways, it... it's much more

(14:54):
caloric dense. And so because gain, or composition of gain, changes more towards adipose as the
animal gets older, that's what makes calories so much more important. So a lot of times when...
when we talk about the multiple segments of the beef industry, uh... that's why... well, and even,
even when you want to go to dairy and everything else, most of the animals that we're mostly

(15:16):
focused on are post pubescent animals. So the animal, that... that stocker background or
calf is typically at that point where... where they're starting to put more calories in gain
for adipose than they are for... for lean tissue. The dairy cow's doing exactly that. Now, they're a
little bit of a different case because they're... they're making milk, and so there's an awful lot

(15:37):
of... that's actually a very efficient process to lactate, so they... they put a lot of those
calories right... directly into milk. (Tim) Yeah, sure. Sure. So but what you're doing though is
that you're looking at efficiency... (Derek) Yes, sir. (Tim) ...that... that we don't get too big of
an animal cuz she's probably inefficient. (Derek) Mhm. (Tim) Or... or too small because you're not
going to get the end product. And... and when we were talking about this, I was thinking, okay,

(16:00):
yeah! Like the doctor said to lose weight, 200... 2,000 calories a day for right now, you can lose
weight. But as you lose weight, you have to have 1,800 calories. (Derek) Yes, sir. Yeah! (Tim) So
same way with an animal? (Derek) Yeah, so it changes. And it changes as your shape changes,
too. That's part of the reason why this is so hard when it comes. And so, you got to take multiple
measure, if... if you have a way that you can easily capture this data in real time because it

(16:25):
becomes a moving mark. That's where some people might criticize maintenance energy requirements
is because they'll say, "Well, yeah. What he's saying is right. That's accurate, but the thing is is it
changes for tomorrow." Right? And so, what the heck? You know, I'm... I'm changing a moving...
or I'm... I'm chasing a moving mark. It's like... well, if I've got an easy way to... to capture
that on a day over day regular basis, well... I can continue to adjust things like that. But

(16:48):
you're 100% correct. As your as your body size changes, so too is your caloric requirements.
And... and it's more, it's... it's really related to shape. So really what... what we're chasing
here is we're kind of trying to chase the more spherical cow. Um... because a sphere is typically
has the optimal, uh... ratio of volume to surface area, and so if... if... if a cow, or a feedlot

(17:16):
steer... whatever, has the same density, so there's the same pound of cow in per cubic meter,
then... then a sphere will optimize the amount of cow with a minimal amount of surface area
related to it. And... and so... in fact, that kind of represents itself in... so we use right now,

(17:39):
because we haven't figured out a way or, um... previously to use surface area in a realistic way
to measure these things, what we do instead is we measure body weight. Right? And so the way... what
we do with body weight is we take body weight, then we take out the amount of body... amount of
that body weight that we think's associated with just digested that's in the digestive tract

(18:00):
(we call that shrunk body weight), and then we raise that to the 3/4 power. Right? Or the 0.75
power. So, and... and that... that's figured out... that's been figured out previously from a bunch
of experiments that were done where people just looked at those relationships of ener... fasting
or maintenance energy costs relative to... to body mass. The... if cattle were spheres, we'd raise it

(18:25):
to the 2/3 power because... (Tim) More efficient. (Derek) Yeah, and be more efficient. Now the
problem is, is right now if I, when we do things on a body weight basis, I'll go get animals that
are all the same body weight and... because that's how we market cattle a lot of times. It's just, I
need a calf of this size, or of this body weight, and it's presumably the same age, but we don't

(18:48):
know that a lot of the times, um... and we know hide color. (Tim) Yeah... yeah. (Derek) That's...
that's about, you know, that's about it. So I mean, I need want heifers or steers, you know...
black or red hided, black white face... whatever it is that a person wants to get. We know those
things, and we know... and we know body weight, so I can... I can work with buyers to get those animals,

(19:08):
um... pretty, within certain thresholds. Problem is, when I close those cattle out,
or if I look at their subsequent performance when all other things are being equal,
well, some of them are going to... some of these animals are... are going to perform,
or they're going to need about two to three... the cost to feed them might be two to three times less
than other animals than they all start... they all seem to start in the same place. Well, that's...

(19:31):
that's... that... that kind of really demonstrates some of the inefficiencies associated with doing
things on a body weight basis. (Tim) So are we looking then at lower or higher surface area
to be optimal? (Derek) So the... so generally, surface. So we call it the law of surface area, so
essentially, we think that there's a fixed amount of caloric loss per square meter of surface area.

(19:52):
So what you really want is you want that animal that has lesser surface area per unit body weight
than... (Tim) Okay. (Derek) ...than the other way around because... the really cool thing
about this, because energy is really important. We also know energy's conserved. No more of it's
getting made in the universe. And so, you've got to get it from somewhere, and what you lose,

(20:14):
you got to account for. And so effectively, warm-blooded critters, like humans and cattle,
we have to get energy every day from something else. And... and because we live in an environment
that's too typically cooler than our internal body temperature, that means we're radiating heat right
now. So you've all seen this if you ever look at a... one those FLIR cameras... (Tim) Yeah. (Derek) So

(20:38):
I mean, you can always pick something out... a warm-blooded critter out against that, and that...
that's because the surface... or the surface temperature of the body is greater than the
surrounding environment. (Tim) We're using like... we're using energy. (Derek) Yeah. (Tim) So...
so we think about muscling then. So a highly muscled animal is going to have a... two animals
that weigh the same but one's more muscled, they're going to have a lower surface area

(21:00):
on the highly... highly muscled one, probably. (Derek) Perhaps. It's... that... that gets into a
composition of gain question which is, that's... that's different. Um... maybe, but... but you
probably could end up in a scenario where you get a lot more adipose in there. Well... actually,
the animal that has more adipose is going to be... (Tim) Or fat. (Derek) ...more efficient. Yeah...
yeah, or fat because, I mean, the double-edged sword of that is, um... that actually provides

(21:23):
some insulative property,... (Tim) Oh, sure. (Derek) ...reduces... reduces feed... or reduces
heat loss and some things like that. That's ultimately where we really want to go with
some of this stuff is we want to get towards... so what we know to date is this law... it was pretty
well accepted concept of this law of surface area that basically, the... the... the cow...
the caloric requirements, which really drive the bus for feed efficiency and feed requirements,

(21:46):
are directly proportional to the surface area of the body. However, we still see some variance even
around that when we correct for that. And so, the reason for that is because we see changes in what
we think is different surfaces of the body lose heat at different rates. And we know things like
this. Like, so cattle that are more acclimated to higher, uh... heat tolerances and things like

(22:10):
that, they have ways to dissipate heat better (Tim) The Brahmans. (Derek) The Brahman cows.
He's got the big, long ears. (Tim) Yes. (Derek) Has got a, you know,
larger naval a lot of the times. More ex... excess skin around the, uh... uh... um... around the...
the brisket and some other parts of the surface. It's... it's really increasing its surface area,

(22:31):
and it's doing that so it can dissipate heat... (Tim) Right. (Derek) ...in... in the face of... of
greater thermal stress, or heat stresses. (Tim) So what you're doing, you... that you mentioned that
you saw your... your son's or somebody's game, and... and... and they were doing this 3D imaging,
we could do that with cattle, too! (Derek) Yeah! So, yeah. That... yeah. What really, yeah... kind

(22:51):
of what really got us... got... got us thinking about this as I was having this conversation with
some of my colleagues where... so my son likes to play video games, and back then he had an
Xbox with an Xbox Connect (which is just a camera sensor on... on a game console). And essentially,
it works where, you know, um... you can play games, you move around, the camera kind of figures

(23:13):
out how you move around, it moves the character around on the screen, kind of thing like that. But, and
that's all fine and grand, but as... as we were setting that thing up for him, you had to, uh...
you have to go into this kind of backend system to calibrate the camera. And so when that happens,
you actually... for some time, see what the camera is actually seeing in the environment. And so as

(23:34):
we're calibrating this thing, I'm realizing this sensor is like wrapping pretty well around the
surfaces of his body in relationship to other things in the room, right? And it can clearly
delineate him, and it's like, holy smokes! It's like, if you can just, I mean, that's a computer,
and it's pretty easy if I can just have that computer capture that image, and then take that

(23:57):
image and then have it count the... the square centimeters... whatever, now all of a sudden,
I've got a way to rapidly, and hopefully pretty accurately, measure... measure surface area of...
I mean, you could do that on... on him when he was calibrating it. And I was like... well,
the real thing is like they're doing... they're using this for entertainment, video games! Man,

(24:19):
if we could do this for... we could... we could put this stuff to work if we could
actually use it in a... in a meaningful sense to measure the surface area of a thing like a cow,
or really any other warm-blooded animal. (Tim) And you would do this all through their
lives? (Derek) Oh, yeah! Absolutely! That's... yeah! And so, what you can do... so essentially,
it's... it's a snapshot in time, right? So if I essentially look at an animal, it's like... okay,

(24:42):
well, I... I have... here's the surface area of that animal. Now I have a more accurate way than
just using its body weight to figure out what it maintenance energy cost is. What that does is,
that tells me effectively how many pounds of feed. So if everybody's getting fed the same thing,
how many pounds of feed the animal with higher caloric requirements going to need more pounds of
feed that it uses for maintenance, which is going to get used first, which means the amount of feed

(25:04):
that's left over to support growth or lactation is less. And so... and so, functionally, that's that
animal that has that higher maintenance energy cost, and every... all things else are equal.
It eats the same... eats the same type of diet, then... then that animal is going to make less
product per pound of feed... (Tim) Right. (Derek) ...that they eat. And so, if we can identify those

(25:26):
animals, then we can make management decisions with those animals, right? So like,
if we talk about like the growing beef calf... well, I can look at those animals, and I can say,
"Okay. Well, this one has a higher surface area relative to its body mass right now. That means
it's going to have higher energy costs." I can either change the type of diet that I'm going
to feed it, or I might move it into a different type of management systems that already have some

(25:47):
inherent losses in efficiency. Maybe I move into like a grass fat program where the animal grows
slower, um... but I'm not using some higher cost feeds associated with what I typically see in a
confinement setting. Um... so I can capture, maybe I can optimize values in those type of settings.
Maybe I can go into a non-hormone kind of treated, um... system where I also have some things that I

(26:09):
give up, but maybe I have less to give up because that animal's already going to be a little bit
less efficient. And what we can do is we can... we can consistently measure this. And ultimately,
we can get to a place where maybe we can even make informed marketing decisions. Because a
big challenge right now, if you move off of like a heifer, and you go into just... like if you go
to like the terminal animal, um... identifying in providing information to producers in a

(26:35):
way that allows them to accurately identify when that animal's effectively done growing,
when I've... when I've reached physiological maturity or that highest carcass value, if I can do that
within a pen setting, target that animal and then subsequently market it, there's tremendous

(26:56):
value in doing that right now. Cuz a lot of the ways that cattle are marketed right now
is we optimize loads, and it's tedious to... and a lot of times our pen sizes are greater than...
than a truck load. And so, either pens are closed out, and so some animals that still had some grow
left in them get go, or I make them all go, but then some of those calves in that pen... well,

(27:16):
they were done a couple weeks ago! So essentially... (Tim) You waste a lot
of money. (Derek) You waste a lot of money! They were eating feed, and they weren't really
giving you much... much more back in carcass value or anything like that. (Tim) All right.
(Dr. Derek Brake) If you want to start an argument amongst a bunch of cow people, or a bunch of... at least a bunch
of nutritionists and management type of people, is you start talking about what the best cow size is,
um... because there's... you go to some parts of the country and people tell you, "Oh,

(27:40):
you need small frame, moderate size cows." You go to other parts of the country, "No, I need biggest
cow I can get," type of deal like. (Tim) Depends on where you're at! (Derek) Well... well, just,
so... so environment plays a big piece of it, right? But... but really, um... it's... it's where
you have to match it, right? Like so, what you're really trying to do is you're trying to match the
cow that can fit within the environment that you have. Right? And you're trying to optimize... I

(28:05):
mean, the other... another good way to start a really... or start a pretty heated debate
is you can also talk about how do we measure the best efficiency in that cow/calf system because
it... should it be... should it be number of calves? Should it be pounds of calf per acre?
You know, all sorts of other type of metrics in there. At the end of the day, what this
all really alludes to is it's really difficult to optimize, um... in... in kind of pastoral settings

(28:32):
more extensive systems, which is the modern US beef cow/calf model. It's really really hard
to identify efficient and inefficient animals. A lot of times the less efficient cow... well,
she sneaks along inside of that system because what we really use is the metric that's typically
the culling metric is... is the ability to achieve a pregnancy. (Tim) Yes! (Derek) So as long as she

(28:54):
gets pregnant again, then she doesn't get culled, um... even though she might be taking more acres
to... to make that calf for you. Right? And so, what we're really hoping to do with this specific
study is we're trying to come up with a system or a solution that would allow feedback information
into... into that cow/calf production system that allows for individuals to optimi... you know,

(29:21):
identify this... this heifer or cow is more efficient than that heifer or cow. And so, if I
can... if I can manage these type of... these type and kind of heifers or cows, and I can do that
within my system, then what I'll ultimately end up realizing is a greater amount of pa... greater
pounds of calves... marketable calf, within my farm. Which I... like I said, we can talk about,

(29:46):
you can argue about efficiency, but I don't think anybody will argue with me that ultimately,
I mean, what you end up doing, the salable product from a... from a cow/calf system is pounds a calf
weaned on a farm basis. Right? (Tim) So would this efficiency affect milk production then? I
mean, are you looking at that, too? (Derek) Possibly. This study's focused on develop...
the developmental heifer. (Tim) Okay. (Derek) And so, um... and so what we're really trying to do is

(30:10):
we want to come into heifers, um... right around that age of weaning, um... early in their life,
and then we're going to do some things nutritional that we think actually influence mature body size,
and so we're going to feed some of them a diet that lets them grow faster... (Tim) Through
grains? (Derek) ...versus other diet. Yes, so may... a higher grade. A higher caloric density
type of diet. Um... not anything too excessive, but on the... on the faster end of what you'd

(30:35):
probably see in a commercial environment. And then we'll feed a more traditional,
kind of a slower developmental type of diet. And we'll mix and match this across different heifers
within the cohort. And then we're going to look and see how... how those nutritional treatments
influence their surface area. We're going to directly measure, um... their maintenance energy
costs. We do that, um... we have systems. We have, um... some equipment on campus that they're

(31:00):
called "open circuit indirect calorimeters." So you... you measure respired air. So for those of
us old enough to remember what a telephone booth looks like, these basically look like a telephone
booth, um... that, um... the animal's head is placed inside there and, um... and then that
allows us to capture all the respired air for a pretty short period of time. It doesn't take that

(31:25):
long to capture this type of data. And... and we measure how much oxygen they need. How much CO2
they produce. How much methane they produce. And from that, we can actually figure out, um... their
caloric energy losses. And so if you do that in... in a state, um... where they're below maintenance,
then you can figure out essenti... you can directly measure the maintenance energy cost. And

(31:48):
so what that allows us to do is take our current surface area measures, so this system that we've
developed using a bunch of computer sensors, which is in place to capture surface area. So we'll...
we'll capture surface area of the animal using that system, and then simultaneously, we'll...
we'll put it in... into these indirect calorimeters, we'll measure their... we'll directly measure
maintenance energy cost, and we can study that relationship and see how that changes in response

(32:13):
to different planes of nutrition and also in changes. So changes in growth size, and at the end
of this study, what... what's going to happen is, so we take... we take all of our heifers, we're
going to put them through a different programming type of a system, then we're going to breed them
all. And then at later... later in gestation, right before they calve, we're going to do this

(32:33):
again. We're going to say, "Hey, how do these changes during growth relate to when... when they
were in late... mid to late stages of pregnancy?" So when they were developing a calf in utero. And
then we're going to follow it 30 days after they calve as well. And so, ask that question when
they're lactating and... and when they've got a calf at their side. And so in order to do that,

(32:56):
we actually have to... so we got to milk a bunch of beef heifers, um... because you got to count
for the amount of calories that are spent in milk. (Tim) Oh, really?! (Derek) Yeah. So...
so you got to do things like that. So, um... but, yeah. So we're going to do this at multiple points
throughout these... throughout these animal's life so we can... so we can better understand
this relationship. Ultimately, be able to take that information, make it more accurate,

(33:19):
so that what we can do is you can take animals and you can ask these questions as they change
different things that they're doing with their body, different products that they're making.
Whether they're making calf, whether they're making milk, whether they're making body tissue,
and say, "What's this? How's this all relate to these surface area measures?" And the... the goal
is that you come up with a system that, you know, is pretty easy, pretty passive. I mean,

(33:41):
we can basically set this up, and... and you can capture... surface area scans pretty, you know,
pretty passive sense. So it's not very laborious to actually collect this type of data, and... and
then you... and then you can feed this back. You can translate it into a... into a number that a
lot of... a lot of producers can understand. Like you know, I mean... you can put it... because...

(34:03):
because calories are so important, I mean, I could tell you, "Well, here's the caloric requirement
of this one relative to that one, and so you might want to make selection decisions on that."
You might want to make selections, I mean... you can take it to other things. You can say, "Well,
this is the type and kind of grass that I have, or this is the season that it is. So functionally,
this is how many acres of forage this critter is going to need in my production system,

(34:24):
or... or this is the... this is the amount of... this is the feed cost, the direct feed cost, of
this one versus that one. (Tim) Because you might even say, "I need to switch from a spring herd to
a fall herd" (Derek) You could... you certainly look at that. (Tim) Just... just to... just to
make... make use of the better efficiencies for example. (Derek) That gets... that gets really
complex. (Tim) Yeah, it does. But it gets on everybody's, uh... uh... different farm. Now, will you also follow

(34:48):
her off... her offspring to see how herit... heritable this is? (Derek) So... so for this
tra... so, so Dr. Decker, Jared Decker, um... he's going to... so he's the geneticist in this role.
So I mean, I'm... I'm the guy who's doing the... the nutrition/bioenergetics piece. Gui DeSouza is
doing... he's the one who makes the... our... who facilitates our ability to collect, to capture,
these three-dimensional images. Dr. Decker is going to come in, and we're going to... we're

(35:12):
going to genotype these animals. And so we're going to... we're going to try and identify the
genes associated with the more efficient and less efficient animals as deter... and... and
as it relates to surface area. So hopefully, what you can actually do is come up with better genetic
predictions of efficient and inefficient cows. Because ultimately, you want to do two things.
So I mean, a lot of times... I'm the... I'm the nutritionist, right? So I mean, the way I like

(35:37):
to tell a lot of people when you think of like nutritionists and geneticist for the most part,
nutritionist's kind of like car mechanic, and geneticist's kind of like the engineer,
right? (Tim) Sure. (Derek) So the engineer makes the problems, and the... and the...
and the mechanics got to fix them, right? And so, really what I... what I hope to do is, you know...
I mean, I... I got the cattle that I got, and I'm just trying to make them the best thing that they
possibly can be, right? Because that's in real time what I'm trying to capture value off of,

(36:02):
right? I'm not in... I'm... I'm not insensitive to the fact that we also need to make the next
round of them as well. (Tim) Right. (Derek) And so... and so what we're hoping to do is two-fold,
right? So we can figure out how to optimize the value and... of... of what we got with a system
like this, but hopefully we also are improving the tools that we have available to make a better

(36:24):
next round. So then the next round that comes by... well, they're even better than the last
one. (Tim) Right. (Derek) And so we get better as time goes along as well. (Tim) Cuz all you do...
I mean, it's not all you're doing, but they... when they go up to, uh... to, uh... drink, you
get their weight, and also you have this little machine scans them really quick. (Derek) Yep, you
got it. It's just a... it's just a... it's just a whole bunch of sensors that we put around

(36:46):
them and there's various ways that we can... we can trigger it right now. Um... and so... but, yeah...
you can certainly use... you can use waters as a location. You can use bunks as a location. You can
use working facilities. It just depends. That... that can all be adapted quite easily from, um...
with the system that we have... so. (Tim) And like you said, the average is 44 cows... average,

(37:09):
nationwide. (Derek) Yes, sir. (Tim) So this could be used on all sizes of... (Derek) Well,
yeah. So that's what we're really trying to hope for. The average of the US beef herd's 44 cows,
um... per operation. And... you know, and your cows are obviously very valuable, but you know,
a lot of times that... that's not enough when we... even... even with the price of calves
where they're at right now, a lot of times that... that's not enough to cash flow some

(37:32):
really expensive equipment, some real laborious type of things, right? That's why, you know,
we see a lot of people use cows... you know, I got cows on the side type of thing, right? You know,
I got some cows at home, and I do this thing, but you know, also... I'm also working in doing things
like that. And so, what we're hoping to do is come up with some systems that you can actually provide
solutions for producers like that, that... that aren't very intensive. They're based on some...

(37:57):
some... maybe some intensive biology, but... but from the... the ability to capture the data,
and the accuracy of the data, are... are... are not... the accuracy is very good, but the ability
to capture the data is maybe not too hard. And so what we can do is you can provide some
real-time feedbacks for some folks who otherwise don't have that information at their fingertip

(38:17):
right now. (Tim) Or I could be a... if I'm a small... smaller producer, but I want to buy your
heifers to breed cuz I know they're efficient. (Derek) Sure! Yeah, so that... so marketing is...
at the point of marketing is one of the places where I think of this as being one of the most,
uh... critical times to be capturing this type of data. I mean, basic... and you know, for the most

(38:38):
part you know, cattle are marketed traditionally two to three times at least in their lifetime,
um... at least terminal animals are... and, um... non-terminal animal... well, they're... all of
them are two to three times in their lifetime, some of them just happens within a year or two.
Um... the... the... the heifer, you know, we can do exactly like what you just suggested.

(39:01):
I've got her weaned off, and you know, maybe you want to buy her to breed her. Maybe you want to
look into a different development type of things. So you might target a different animal, one type
of animal versus another type of animal because it fits within your resources. Or you might make some
informed management... maybe... maybe you decide, "Well, I like the genetic makeup up of those,
but you know, right now they don't look like... it looks like for me to really capture that for

(39:22):
those animals to be successful, maybe I need to manage them in this way versus that way,
um... to really set them up for success so that I can have a higher pregnancy rate, so that I can,
you know, either first or second calf pregnancy rates (which is a lot of the times the biggest
challenges that you run into in... in keeping a heifer around in your herd). That's where a

(39:43):
lot of times they'll... they'll fall out, um... because they just... they don't fit in the system,
right? (Tim) Right. Because a lot of people if they don't breed back that first cycle,
they're gone. (Derek) Yeah, that's typically the, uh... that's typically the number one,
uh... culling metric that a lot of folks use in their... (Tim) So would it be worth if I'm trying
to build my herd good genetics to purchase some of those? I'll put up with that just to get that

(40:08):
good genetics to get something started? (Derek) Sure, I mean, it's... it's optimums, right? Like
I think that's... that's... and... and this is no different from all of it like, you know... I
think we get our se... it's a very human thing to kind of to focus on the extremes, right? The best.
The worst. Right? (Tim) Right. (Derek) Um... but you know, for... for a lot of things in biology,
particularly with managing cattle, sometimes it's... it's kind of like that Goldilocks type

(40:31):
of deal. It's like, you know, this one's too hot. This one's too cold. This one's just right. And
so, it's... sometimes it's really hard to, when... when we're not looking for the extremes, right?
To... to really look for the one that's... that's optimal, right? And so, if it was easy to do,
we'd already be doing it, right? And so... and so we're trying to actually kind of give people that

(40:52):
information that... that, you know, you... you... you couple that with some other information about
your operation, you can really figure out what you're doing. (Tim) So if... here in Missouri,
I'm seeing a lot more folks talking about grass-fed, grass finished. (Derek) Yep. (Tim) Is
there a different type of animal for each... for a feedlot versus a grass finished? (Derek) Well,

(41:13):
so I think so. So like I said, like so drawback to the, so... so grass... so... so if you got the
forage out in the pasture, so that's typically one of the cheapest ways to get calories into a cow is
to let them go graze it, right? Because the energy content of stored forages, like a hay, is about
a third of other types of feeds that we harvest, like corn, um... but hay doesn't cost a third of

(41:40):
the price of corn. (Tim) Right. (Derek) A lot of times feeding things like hay is really expensive.
So, you can do grass finished as a system to do that. A challenge to grass finish is, while it's
cheap from a standpoint of getting calories into the animal, it takes them longer to grow. Right?
Because there's less calories per blade of grass, or per acre, out there than there is in maybe some

(42:02):
traditional finishing diets. And so, there's... there's probably animals where you can optimize
their... their ability for growth in those systems versus other systems. What happens right now in a
finishing scenario is basically we're treating all cattle like they're race cars, right? So
we've got all this... I mean, the beef industry's been great at develop... as really learning how to

(42:25):
optimize the way we feed the best calf. How we... we've got various technologies like, uh... uh...
implants that we use, beta-agonist, some other feeds, uh... type of additives that... that really
optimize growth. And so we use these things, and those things all work really, really well

(42:46):
at getting the most out of the best calf. But the average calf, sometimes those things don't pay off
quite as well, right? Because maybe some of those, they just... they can't capture the value in all
those technologies. So that's where... but the... but the consumers, uh... beef consumers are very
interested in other types of production systems. Some like grass fat program, non-hormone treated

(43:08):
programs. The... the challenges with some of those programs are is that we give back some production
efficiency, right? They... they grow a little bit slower, um... and things like that. And so,
there's... at the producer level, there's always this kind of conflict. It's like... well, I can
do this type of system and... but am I losing some value that I could have otherwise captured? Well,

(43:30):
if we can identify the animal that maybe had less value anyways because it had a less...
had less potential to... to capture all the value in our current fish... finishing systems... well,
maybe we can optimize the value that we can capture out of those animals by putting them
into some of these other production systems, into the grass fat system, into a non-hormone treated

(43:50):
system... things like that. (Tim) Yeah, cuz if you put a race car in... in the... in the grass fed,
they may not benefit there as well. (Derek) Yeah. You're not going to win too many Nascar
races with a 1984 Yugo, right? (Tim) That's right. That's right. You know, the other thing
that intrigued me is that you put them over in... in these... I can't remember what you called them.
Where you measure CO2 and methane emissions. (Derek) Sure. (Tim) Efficiency becomes... comes

(44:11):
into that, too, to play, doesn't it? (Derek) Yeah. So... well, so that's a big piece on how we change
things. Um... you know, cattle... there's a lot talked about with their methane... the amount
of methane that's lost, so that that gets into some more of the internal mechanisms of... of how
things are happening within the rumen, in other parts of the body as well. So I mean, CO2 roughly
represents basically fuel in the body that's been oxidized, and then... and then methane is itself

(44:37):
has energy content in it, and that happens from... that's a consequence of fermentation, a pregastric
fermentation. Um... the cool thing about this is... so there's a lot of really complex things
that happen within the body that are what lead to differences in energy requirements, and...

(44:57):
and those... and those can be going in lots of different ways, and they can go... be in a lot of
different ways across different individuals. But, because energy is neither created nor destroyed...
(Tim) There's a thermodynamic law about that, isn't there? (Derek) Yeah. Even... even though...
even... even though they might... we might have all these different complex things going on inside the

(45:17):
body that contribute to that, if I can measure the heat loss from the surface of the body... well,
it doesn't matter that if one calf has a higher maintenance cost because this stuff's going on
versus this other calf has got an elevated, uh... maintenance cost for other reasons, those should
both be directly proportional to heat losses from the body. (Tim) Yeah. (Derek) And right now,

(45:41):
we think that those are directly proportional to the surface of the body. So... so...
so really what we can do is, we don't have to get lost all the time in some of the... in some of
these other things that are happening within the body because we can just... we can capture some
things that we know about thermodynamics and how energy works in the universe,

(46:02):
and we can relate that in a real practical way to... to cattle production systems by... by
looking at differences in surface area associated with the body. (Tim) So the surface area gets...
gets into efficiency of feed, but also... then also, maybe even the emissions. (Derek) Oh,
yeah! Well, so we... we're... we're hoping to learn... we'll figure that out right?! Like
that's one thing... that's... that's actually... so there's an awful lot talked about when it comes

(46:25):
to methane production... (Tim) Right. (Derek) ...um, because of its... you know, concerns over,
um... environmental impacts associated with... with cattle production. There's some data actually
out there that would actually suggest that under some circumstances, methane production is not all
that bad of a thing because it actually optimizes how much things can be fermented within the rumen.

(46:48):
So what happens is hydrogen... so when in fermentation systems like the rumen,
you end up with excesses of hydrogen, so it kind of slows down how fast things can be fermented.
So when I'm in like a forage system, and you can only ferment so much forage, and that limits the
cow from taking its nex... next bite, then, um... the... the ability to take this extra hydrogen

(47:11):
that's coming off of this fermentation (and that's what's slowing all this down), and put that on
CO2 that gets converted to methane. So you go CO2 (which is the most oxidized form of
carbon) to CH4 (which is the most, what we call "chemically reduced form of carbon"),
and... and so it's the most efficient at a molecular scale at moving hydrogen out

(47:34):
of a system. And if you can do that, that allows enzymes in the rumen to function more efficiently,
more rapidly ferment forages that are in there. So actually, it's probably... we probably don't
want to chase the cow that makes no methane. I mean, that's maybe a little bit controversial.
I mean, there's some folks who disagree with me. (Tim) Wouldn't be very efficient. (Derek) But...
but... but that's the thing, you might end up with a system where... especially where we're

(47:56):
asking a beast to capture the most amount out of a... out of a fibrous feed, because that's
really cattle's special power, right? Is they go out there, and they get a bunch of forage,
and they turn it into stu... some things that you and I would be on a pretty hard
diet if we were trying to eat that stuff, right? (Tim) Right. (Derek) Um... and, but you know,

(48:17):
we can let cattle go out there and they capture all the nutrients in that stuff,
and they convert into something that's actually really high nutrient value for us, right? And so,
we're definitely going to learn how methane emissions relate, um... with these differences
in surface area. Um... and we're going to measure things like intake because we have

(48:38):
feed monitoring systems here at the University of Missouri that let us measure daily intakes.
And we're going to relate all those things, and we can look and see how all of this relates at
the end. So hopefully, that... that gives us better insight into... into things like that,
into methane emissions and other things as well. (Tim) So it looks like this project can help small

(48:59):
producers, large producers... it's going to help efficiencies with... with... with feed, but also,
we'll... the next step would be we'll find out how it does on... on environmental impacts. (Derek) Sure.
That's the whole thing. (Tim) That's... that's what neat. (Derek) We're really trying to optimize
the efficiency of the whole system. The beauty is, is when we can optimize the efficiency, which
really optimizes our feed costs. It... it... it... it also, we're trying to help carbon capture as

(49:22):
well because we want more carbon from... which is the primary element in the feed, we want most of
that to go into tissues of the animal versus other things, right? Because... or the more of that that
we can make occur, then what that does is that results in more salable beef, more pounds of milk,

(49:44):
more things that... reason why folks feed cattle, right? (Tim) Who knows? Even maybe less time on
the feedlot? Less time. (Derek) Yeah! Yeah, so you can end up with less days on feed. There's...
there... there's a lot of different things that, you know, maybe we don't know. I mean... or a lot
of these different things can happen simultaneous to one another. It's just kind of figuring out,
um... what... what we're really trying to do is come up with a system that gives us a

(50:08):
way to more accurately figure those things out in a... in a real time setting. So basically,
go from painting with a really broad brush and maybe go just a little bit... little bit narrower
one so we can paint by numbers or something like that. (Tim) Yeah, exactly. All right. Well, Derek,
this has been... this has been fantastic, uh... conversation. And congratulations on this grant!
It's going to go a lot of different directions. (Derek) Yes, sir. I think so. (Tim) Which is

(50:31):
really neat. Which is really neat. (Derek) We're excited to do it. (Tim) All right. Well,
thanks. This is it for Tim's Take! And tune in to us next time. We'll see you. Bye. (Derek) Thanks.
[♫]

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Tim's Take Episode 31 | Derek Brake | Does Animal Physiology Impact Feed Requirements?

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.css-14f5ked{margin:0;word-break:break-word;display:-webkit-box;-webkit-box-orient:vertical;box-orient:vertical;-webkit-line-clamp:2;overflow:hidden;}Tim's Take Episode 31 | Derek Brake | Does Animal Physiology Impact Feed Requirements?