Slide 1
Hi there. I'm Hans H. Stein, and I'm a professor at the University of 
Illinois. And I'd like to talk to you today about corn and corn 
co-products fed to swine.

Slide 2
First, I'd like to talk a little bit about the composition of corn. And 
a typical corn grain contains about 11.3% water, 8.3% crude protein, 
3.7% fat, 1.3% ash, and 62.6% starch. And then on top of that, we also 
have some fibers, and that is divided into NDF at about 9.1%, ADF at 
2.9%, and then we have lignin at about 0.3%. We feed a lot of corn grain 
to our pigs, and when we feed corn grain we get exactly the composition 
that is shown here. However, corn is also used for many other purposes, 
and as the industry utilizes corn, there is usually a part, or a 
fraction, of the corn grain that cannot be utilized for the primary 
purposes. And those fractions are usually available for the feed 
industry and therefore also for the swine feed industry. What happens on 
most occasions is that industrial use of corn grain results in removal 
of the starch. There are a few exceptions to that, but for most 
purposes, starch is removed and then we end up with the other components 
in the corn grain except for the starch. And if that happens, then 
obviously all the other components will be concentrated because, as 
appears here, starch is almost 2/3 of the corn grain. And therefore if 
you remove that starch, then you end up with a much greater 
concentration of all the other components. So, in most of the corn 
co-products we work with, we have greater concentrations of crude 
protein and fat and fiber than we have in corn grain. Sometimes, some of 
those other nutrients are also removed, and therefore we can have wide 
variety of concentrations of nutrients in the corn co-products that are 
available to us.

Slide 3
If we look at the concentration of metabolizable energy in corn grain, 
then we have here values from nine different experiments that have been 
conducted here at the University of Illinois over the last few years. 
And you'll see here that the concentration of metabolizable energy in 
these nine different sources of corn grain, on average, has been 3,846 
kcal/kg dry matter. And you'll also notice that the variation in the 
energy concentration in corn has not been very big; it's about two 
percentage units, and there's less variation in the metabolizable energy 
in corn than there are in most of our other ingredients.

Slide 4
We can also compare the digestible and metabolizable energy of corn to 
that published from other sources. You'll see here that the nine sources 
that we have worked with at the University of Illinois, on average, 
contain 3,950 kcal of digestible energy and 3,846 kcal of metabolizable 
energy. And if you divide those two numbers, then you'll get an ME:DE 
ratio of 97%. Those values are very close to the values that have been 
published by NRC in 1998 at 3,961 kcal/kg dry matter and 3,843 kcal/kg 
dry matter, respectively. And NRC also reports an ME:DE ratio of 97%. 
And if you go to Europe and look at published values there, then we have 
INRA values that were published in 2004, and the average DE in the INRA 
tables are 3,927 and the ME is 3,844. And it's clear from this table 
that the European values are also very close to the values that have 
been determined here at the University of Illinois, and also that have 
been published by NRC.

Slide 5
Now, if we look at the corn co-products, we can roughly divide them into 
two separate groups. One group of corn co-products are the co-products 
that are produced by the ethanol industry, and the other group consists 
of all other co-products. The co-products from the ethanol industry 
include distillers dried grains with solubles (also called DDGS), we 
have high-protein distillers dried grains (or HP DDG), we have corn 
germ, and we also now have de-oiled DDGS and low-oil DDGS. So we have at 
least five different co-products produced by the ethanol industry. The 
co-products that are available to us from other industries include corn 
gluten meal and corn gluten feed, and both of those products are from 
the wet milling industry. We also have corn germ meal, which may be 
produced by either the wet milling or the dry milling industry, and we 
have hominy feed, which is a co-products from the corn grits industry.

Slide 6
If we look at the composition of the co-products from the ethanol 
industry, then we have here DDGS, DDG, high protein DDG, and corn germ. 
I have also included corn grain in this table here. And we will see that 
the concentration of crude protein is greater in all the corn 
co-products compared with corn. It is about 27.5% in DDGS, 28.8 in DDG, 
and 41.1 in high protein DDG. And then we have corn germ with only 14%. 
Fat is also greater in DDGS than in corn, and it's much greater in corn 
germ than in corn because the corn germ contains the majority of the fat 
that is present in the corn grain. However, HP DDG has a relatively low 
concentration of fat. As we saw before, the corn grain contains 
approximately 65% starch, but most of that starch is removed when we 
come to the corn co-products. So DDGS contains only 7% starch, DDG 3.83% 
starch, HP DDG 11.2% starch, and corn germ about 23.6% starch. The fiber 
can be expressed as NDF, and the corn grain contains less NDF than DDGS, 
HP DDG, and corn germ, and also less than DDG. So we will see that the 
fiber concentration is much greater in these co-products than it is in 
corn. And if we look at lysine, we'll see that all the corn co-products 
contain more lysine than corn, and it varies from 0.78% in DDGS to 1.23% 
in HP DDG.

Slide 7
If we look at the metabolizable energy in the corn co-products, we'll 
see we have corn here at about 3800 kcal/kg dry matter, as we showed 
before. DDGS is very similar to corn in terms of ME concentration, but 
high protein DDG contains more ME than does corn or DDGS. On the other 
hand, corn germ contains about the same as corn and DDGS, but if we take 
the oil out of DDGS and produce a de-oiled DDGS, then we will end up 
with a product that contains much less energy than the original product 
that we had. And we can see here in the green bar that the concentration 
of energy is much lower than it is in any of the other co-products. So, 
the conclusion here is that corn germ and DDGS contain about the same 
amount of energy as corn, high protein DDG contains a little bit more 
energy than corn, but de-oiled DDGS contains much less energy than corn.

Slide 8
We also have fat, or lipids, in all our corn co-products. However, the 
digestibility of that fat is different among different products. And we 
have some data here from extracted corn oil, from corn, from DDGS, from 
corn germ, from HP DDG, and also from soybeans. And it appears from this 
slide that the true ileal digestibility of lipids in these different 
sources varies quite dramatically. Extracted corn oil is very digestible 
and the pig will absorb about 95% of the extracted corn oil if we add 
that to the diet. However, if we don't extract the corn oil and leave it 
in the corn, the digestibility is much less, and only slightly above 
50%. So, there is a big increase in digestibility of corn oil if we 
extract that corn oil out of the corn grain. We can also see that the 
digestibility of lipids in DDGS and in corn germ is about the same as it 
is in corn. So that is also much less than in extracted corn oil. But 
when we come to HP DDG, we do see a slight increase in digestibility; 
but, as we saw before, there is not a lot of oil in HP DDG but whatever 
is there is relatively well digested. Full fat soybeans also have a 
relatively high digestibility of lipids at about 85%. So the conclusion 
from this slide is that, although lipids contain quite a bit of energy, 
there are relatively big variations among different corn co-products in 
the digestibility of these lipids.

Slide 9
As we saw before, we have quite a bit of fiber in DDGS and in other corn 
co-products. And the fiber can be divided into insoluble dietary fiber 
and into soluble dietary fiber. And we have here the insoluble dietary 
fiber in the red bar, and the soluble dietary fiber in the yellow bar, 
and the total dietary fiber -- which is the sum of the insoluble and the 
soluble dietary fibers -- in the blue bar. And when we look at the 
disappearance of fiber in the total tract of a pig, then we can see that 
the insoluble dietary fibers disappear by only approximately 40%. And 
that means about 40% of these fibers in DDGS are fermented in the 
intestinal tract of a pig. So the other 60% of the insoluble dietary 
fibers, they will just pass through the pig and be excreted in the 
feces. However, when we look at soluble dietary fibers, we can see that 
they are much more fermentable, so the disappearance is greater than 90% 
in the soluble dietary fibers. However, the concentration of soluble 
dietary fiber in DDGS is relatively low, so although the pig seems to be 
able to ferment the soluble dietary fiber very well, the influence on 
the overall digestibility or disappearance of fiber in DDGS is not that 
great. So, the disappearance of total dietary fiber in DDGS is only 
about 50%.

Slide 10
When we come to the amino acids, we can see that the digestibility of 
most amino acids in the corn co-products is approximately the same as it 
is in corn. The exception here is corn germ, where the digestibility is 
less than in corn grain. But for most of the other co-products, the 
digestibility of amino acids is similar to that in corn. However, the 
exception to that is lysine, which has a lower digestibility in DDGS 
than in corn, and the reason for that is primarily that there is some 
heat damage going on in DDGS when the ethanol industry is drying the 
product after fermentation. But with that exception, most other amino 
acids have the same digestibility in the corn co-product compared with 
corn.

Slide 11
Over the last five to seven years, there have been numerous experiments 
conducted to evaluate inclusion rates of DDGS in diets fed to sows and 
growing-finishing pigs. And based on all these experiments, we can 
recommend inclusion rates of DDGS in diets for the different categories 
of pigs. And based on that, we recommend about 50% inclusion rate in 
diets for gestating sows, 30% in diets for lactating sows, we don't 
recommend usage of DDGS in nursery diets during the first two weeks post 
weaning but after that, we can use up to 30% DDGS in the diets. We can 
also use 30% in the growing-finishing diets, but during the last three 
to four weeks before harvest, we recommend that the inclusion rate of 
DDGS is reduced to about 20% to prevent development of soft bellies and 
soft fat depots in the pigs. However, there are some systems, in 
particular in the Midwest, where usage of DDGS is much greater than what 
has been recommended and we see maximum inclusion rates going up to 40 
to 45% both for sows and for growing-finishing pigs. And many systems 
report excellent productivity based on these diets. However, the 
research to verify that these greater inclusion rates can be used has 
not been reported at this time.

Slide 12
We also have recommendations for high protein DDG and corn germ, but few 
experiments have been conducted with these co-products compared with 
DDGS. However, based on the reported literature, we can recommend that 
high protein DDG may replace all the soybean meal in diets fed to 
growing-finishing pigs, and corn germ can be included by at least 30% in 
diets fed to growing-finishing pigs. In weanling pig diets, we can 
probably include up to 20% of each of these ingredients; however, there 
still is a lack of published research in this area. For sows, we also 
recommend up to 30% of both HP DDG and corn germ in diets fed in 
lactation in in gestation.

Slide 13
Now, that was a little bit about the co-products from the ethanol 
industry; however, as mentioned in the beginning, we also have other 
co-products available to us.

Slide 14
Some of the other co-products include corn gluten meal, corn gluten 
feed, corn germ meal, and hominy feed. The blue bars on this slide shows 
the crude protein concentration in these co-products; the red bar shows 
the concentrations of acid-hydrolyzed ether extract, or fat; the orange 
bars show the concentrations of fiber, or NDF; and the green bars show 
the concentrations of starch. And we'll see that, although all four 
co-products here are co-products of corn, they vary dramatically in the 
concentration of the different nutrients. Corn gluten meal contains 
quite a bit of protein and very little fat, a medium concentration of 
fiber, and a low concentration of starch. Corn gluten feed has a much 
lower concentration of protein, a very low concentration of fat, but a 
very high concentration of fiber and does not contain any starch. Corn 
germ meal also has a relatively low concentration of protein and fat, 
but a high concentration of fiber and also contains a little bit of 
starch. And hominy feed has a low concentration of protein, contains 
more fat than the other ingredients, low concentration of fiber, and 
contains quite a bit of starch. So of all of these co-products, hominy 
feed is the only product that contains quite a bit of starch, whereas 
the other products are very low in starch.

Slide 15
The amino acid digestibility also varies among these co-products. The 
digestibility of lysine is shown here in the blue bars, methionine in 
the red bars, threonine in the orange bars, and tryptophan in the green 
bars. And we will see that hominy feed has a lower digestibility of 
lysine compared with corn, whereas corn gluten meal has a greater 
digestibility of lysine. The same is true for methionine, where hominy 
feed and also corn germ meal and corn gluten feed have a reduced 
digestibility compared with corn, whereas corn gluten meal has a greater 
digestibility than in corn. When we go to threonine, we see the same 
thing, with hominy feed having the least digestibility and corn germ 
meal and corn gluten feed having a digestibility that is approximately 
the same as in corn, and corn gluten meal have a greater digestibility. 
And finally, when we go to tryptophan, we'll see that hominy feed, corn 
germ meal, and corn gluten feed have about the same digestibility as 
corn, whereas the digestibility in corn gluten meal is a little bit 
greater than in corn. So what we can see here is that although all of 
these products are corn co-products, the digestibility of amino acids 
among these products is not the same.

Slide 16
We also know that the quality of the protein varies among different feed 
ingredients. And here, we can see the concentration of crude protein in 
soybean meal, corn gluten meal, and DDGS. And we can see that corn 
gluten meal contains more protein, and DDGS less protein, than soybean 
meal. However, when we look at the concentration of lysine and 
tryptophan, we can see that concentration is much less in corn gluten 
meal, and also in DDGS, compared with soybean meal. And that is easily 
illustrated if we calculate the concentration of lysine and tryptophan 
as a percentage of crude protein in each of these ingredients. And here 
we can see that soybean meal has a concentration of lysine and crude 
protein of about 6.35% and tryptophan of 1.37%, and these values are 
much greater than in the two corn co-products. The reason is that corn 
protein has a reduced concentration of lysine and tryptophan compared 
with almost all other protein sources and also compared with the 
requirement of the pigs. So every time we use a corn co-product, we have 
a low concentration of lysine and tryptophan in the diets, and we need 
to find a way of compensating that, primarily by use of crystalline 
sources of lysine or crystalline sources of tryptophan to compensate for 
this low concentration in corn co-products.

Slide 17
There are not many data on the concentration of energy in corn 
co-products, but some prelimary data from the University of Illinois for 
the concentration of digestible energy in corn co-products are 
illustrated in this slide. And we can see here that corn gluten meal 
contains more energy than corn. On the other hand, corn gluten feed and 
corn germ meal contain less digestible energy than corn. And hominy feed 
contains almost the same amount of digestible energy as corn. So, if we 
include hominy feed or corn gluten meal in the diets fed to pigs, then 
we will not see a reduction in the diet energy concentration; however, 
if corn gluten feed and corn germ meal are used, then we may see a 
reduction in diet energy concentrations and we may have to compensate 
that by adding fat or other high energy feed ingredients to the diets.

Slide 18
When we look at the digestibility of phosphorus in corn and corn 
co-products, we have here data for corn, DDGS, high protein DDG, and 
corn germ. And we have data both without phytase and with the inclusion 
of 500 units of microbial phytase. We will see here that the 
digestibility of phosphorus in corn and corn germ is relatively low if 
we have no phytase in the diets. However, when we look at DDGS and high 
protein DDG, the digestibility of phosphorus is much greater than in 
corn and in corn germ. And we believe that the reason for this increased 
digestibility is that DDGS and high protein DDG are products that have 
been soaked and steeped, and gone through a fermentation process, and 
therefore some of the phytate molecules have been broken, and therefore 
more phosphorus is available for absorption. However, if we add 
microbial phytase to corn or corn germ, we can increase the 
digestibility quite dramatically and get up to almost 60% digestibility 
of phosphorus. In contrast, if we add phytase to DDGS, we don't see a 
significant increase in digestibility, probably because the 
digestibility already was quite high in DDGS and therefore microbial 
phytase does not result in a further increase in digestibility. And the 
same is true for HP DDG, where we see a very small increase in 
digestibility when we use phytase, and not nearly to the same extent as 
we saw in corn. So the conclusion here is that DDGS and high protein 
DDG, they have a high digestibility of phosphorus, whereas the 
unfermented products, which are corn and corn germ, they have a much 
lower digestibility, but the digestibility in corn germ may be improved 
if we add microbial phytase to the diets.

Slide 19
If we look at the standardized total tract digestibility of phosphorus 
in other corn co-products, we will see here that the digestibility of 
phosphorus in corn gluten meal, corn gluten feed, and corn germ meal are 
all greater than in corn if we don't use any phytase. However, the 
digestibility of phosphorus in hominy feed is about the same as in corn. 
If we use phytase, then we can increase the digestibility of phosphorus 
in corn, as we have seen before, to about 60%, and we see almost the 
same increase in hominy feed. Corn germ meal will also have an increased 
digestibility of phosphorus if we use phytase, and the same is true for 
corn gluten meal. However, corn gluten feed does not see an increase in 
digestibility of phosphorus if we add phytase. But corn gluten feed had 
the greatest digestibility without phytase, so the reason we don't see 
an improvement when we add phytase to the diets is likely that there is 
no room for further improvement of the phosphorus digestibility in corn 
gluten feed.

Slide 20
So in conclusion, we have seen that DDGS may be included in diets fed to 
pigs at relatively high concentrations and, by using DDGS at relatively 
high concentrations, most producers can save on diet formulations. 
However, it is important that we know the lysine digestibility in DDGS 
so we can predict the digestibility in the diet, and therefore can 
formulate a diet that contains enough lysine to meet the requirement of 
the pigs. We have seen that HP DDG may replace all the soybean meal in 
growing-finishing diets and be included by at least 20% in weanling pig 
diets and 30% in diets fed to sows. Corn germ may also be included by 
about 20% in nursery diets and 30% in all other diets. And we have seen 
that the phosphorus digestibility in DDGS and HP DDG is close to 70%, 
whereas it is less in corn germ and in corn.

Slide 21
We do need more research to determine the inclusion rate that may be 
used for corn gluten meal, corn gluten feed, and corn germ meal and 
hominy feed if we include that in diets fed to pigs. We don't know 
exactly how much we can include in these diets, but it appears that all 
of these products have good energy values, have relatively good amino 
acid digestibility, and have excellent phosphorus digestibility. We also 
believe that it is possible to include 20 to 30% of corn gluten meal, 
corn gluten feed, and corn germ meal in diets fed to all groups of pigs, 
but we do need research to confirm this. And finally, we do believe that 
hominy feed may replace at least 50% of all the corn in diets fed to all 
categories of pigs.

Slide 22
With that, I want to acknowledge my students and technicians who have 
helped conduct the research I have talked about here. And we do have 
more information about all our research projects at our website, which 
can be found at nutrition.ansci.illinois.edu. With that, I want to thank 
you for your attention, and I hope you will have good luck using corn 
co-products in diets fed to pigs.