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Corn Gluten Feed as an Alternative
Ingredient in Finishing Diets for Senepol- and Angus-sired Steers
M. Poore, J.
Cassady, and G. Benson
Background
In most
situations in North Carolina, beef producers own brood-cow herds and sell
calves at, or shortly after, weaning. This practice limits their ability to
determine how their calves perform after entering the feedlot phase of the
conventional beef industry. This structure hinders the flow of information
back to producers about consumer acceptance of the final product. At the
Center for Environmental Farming Systems (CEFS) beef unit (located near
Goldsboro, NC), we have sought to develop alternative channels for our
calves that would allow us to collect more complete data on the finishing
and marketing of our beef and better serve North Carolina beef producers.
The cow herd
at CEFS is an Angus-based commercial herd with about 110 cows calving each
year. For the last 6 years we have
bred half the mature cows to Angus bulls and the other half to Senepol
bulls. We have followed the
performance of the ˝ Senepol calves, and are now beginning to evaluate the
˝ Senepol cows.
We recently
used the steer calves from CEFS in a two year study to determine the value
of a corn byproduct that is produced in Winston Salem, NC. The wet corn
milling process yields corn syrup and corn germ (which is further processed
to corn oil), and corn gluten meal, a high quality protein feed for poultry
and swine. The primary by-product is corn gluten feed, which has a moderate
protein level (18 to 24%) and is composed of corn bran and condensed steep
liquids that result from soaking the grain in a mild sulfurous dioxide
solution. Because of its fiber content, corn gluten feed is not of much
value as a feed for poultry or swine, and is mostly used in cattle feeding.
Corn gluten
feed is initially wet (approximately 60 to 65% moisture), and in some cases
marketed as “wet corn gluten feed.”
Because not all of the byproduct stream can be marketed in the wet
form, it may also be dried. The goals of our study were to compare wet and
dry forms of corn gluten feed to a conventional corn and soybean meal based
diet and to determine how our Angus- and Senepol-sired steers respond to
each diet.
Method
Over the two
years of the study 40 Angus-sired and 25 Senepol-sired steers were fed one
of three finishing diets. The control diet was typical of an industry diet
and consisted of 10% corn silage, 77% corn and 11.4% soybean meal (dry
basis). The two corn gluten feed
diets had wet or dry corn gluten feed at 35% of the dry matter as a
substitute to the soybean meal and a portion of the corn. Protein and
mineral levels were maintained at similar levels for all three diets.
The steers
were born in February and March at CEFS, weaned in September, and then
shipped to Butner in December where they began their designated diet in
January. Calves were fed for 138 days in the first year and 147 days in the
second year and went to harvest at 15 to 17 months of age. Health,
performance, and carcass data were collected for all calves in the study.
Results and discussion
Feed composition. The corn gluten
feed was fairly consistent over the two years of the study. Wet corn gluten was 35% dry matter and
17% protein (dry basis) in year 1 and 39% dry matter and 19% protein in
year 2. Dry corn gluten feed was
90% dry matter and 26% protein (dry basis) in both years. Each of the diets averaged 14% protein
and 80% TDN on a dry matter basis.
Performance and carcass data. Performance and carcass data
are shown in Table 1. Health and performance of the calves was good throughout both
years. Each type of steer responded to the different diets in a similar
manner. Contrast information listed in the last column of Table
1 indicates which major comparisons indicated differences beyond what
would be expected based on random chance.
The three comparisons we made were (1) Angus- vs. Senepol-sired
calves, (2) control diet vs. corn gluten feed diets, and (3) wet corn
gluten vs. dry corn gluten feed diets.
Note that a comparison is significant when a P value is less than
0.05, which means there is only a 5% chance that the difference observed
between values was simply due to random chance. Representative steers from
the Angus- and the Senepol-sired groups a few days before harvest are shown
in the pictures.
Senepol-sired
steers weighed the same as Angus-sired steers to start the study, but they
gained weight slower and had a lower final weight than Angus-sired calves.
This is consistent with our earlier observations from the western
feedlot. We usually have higher
weaning weights for Senepol-sired calves at CEFS, probably due to their
heat tolerance, but they give up that advantage during the finishing phase.
The main reason for reduced gain in Senepol-sired calves is that they ate
less feed than the Angus-sired calves. The Senepol-sired calves also were
slightly less efficient at converting feed to beef than Angus-sired calves.
Senepol-sired calves had slightly less marbling than the Angus-sired calves
and also had slightly less backfat. Ribeye size and USDA quality grade were
not significantly different between the sire breeds.
There was no
difference in average daily gain between diets with an overall average of
3.3 lbs/day. Calves on dry corn
gluten feed diet ate more feed than those on the other two diets, resulting
in a lower efficiency of converting feed to beef. Carcasses from steers on
all three diets weighed the same, and they had a similar backfat thickness
and ribeye size. Calves on dry corn
gluten feed had slightly more marbling in the meat than the other two
diets. Calves on wet corn gluten
feed had a lower USDA quality grade than those on the other dry corn gluten
feed.
These results indicate that either
dry or wet corn gluten feed can be used in this kind of finishing diet with
minimal effects on either the rate of gain, feed efficiency or carcass
characteristics.
Economics. To determine the
economics of a feeding system, feed prices must be determined. We used market value of ingredients
delivered to the Butner Beef Cattle Field Laboratory which is about 100
miles from the plant in Winston-Salem that produces the corn gluten
feed. Based on our feed costs, it
turned out to be more economical to put gain on the calves using either of
the corn gluten feed diets as compared to the control diet, with no
difference in feed ingredient cost per pound of gain between the wet and
the dry corn gluten feed. We also
found that it was more expensive to put gain on Senepol-sired calves than
as compared to Angus-sired calves.
Economics of
wet vs. dry corn gluten feed will depend on the distance the producer is
from the plant, because of the difference in freight cost for the wet and
dry ingredient. This is because a
tractor trailer load of wet corn gluten feed has about 9 tons of dry matter
while a load of dry corn gluten fed has about 21 tons of dry matter and the
delivery cost per mile is similar.
The relationship between distance from the plant, freight cost, and
the value of wet and dry corn gluten feed is shown in Figure
1
The cattle on the wet corn gluten feed
ration had a lower USDA quality grade, which affects market value and
points to the need to include carcass characteristics in the evaluation of
alternative rations. There were
breed differences in carcass characteristics that affect market value but a
complete evaluation of profitability is beyond the scope of this report. This study demonstrates clearly that
byproducts can be an economical part of the ration when cattle are finished
in our area but that you have to consider the cost of ingredients along
with animal performance.
Conclusions
Our study
indicates that corn gluten feed is a viable alternative feed for finishing diets
in North Carolina. Relative value of wet and dry corn gluten feed, however,
will depend on the distance the producer is from the corn processing plant.
The growth
and carcass data with our Senepol-sired steers confirms our earlier
observations that they grow slightly slower and don’t have quite the
carcass quality of the Angus steers. However, it is important to note that
they did grow quite well and produced very good quality carcasses that are
very acceptable to the conventional beef industry. While Senepol-sired steers did not quite
perform up to the level of the Angus-sired steers we have observed other
advantages with Senepol-influenced cattle including heat and fly resistance
that are desirable in our environment.
Work with
finishing the CEFS steers on alternative feeds at the Butner Beef Cattle
Field Lab will continue in the coming years. We will also continue to study
the F-1 Senepol cows, and how other breeds may be used in crossbreeding
programs with Angus to optimize beef production on North Carolina’s many
cow/calf farms.
Acknowledgements.
We wish to
thank Eddie Pitzer, Andy Meier, Earl Toler and the rest of the crew at
CEFS, and Dean Askew, Greg Shaeffer and the rest of the crew at the Butner
Beef Cattle Field Lab. Also, thanks
go to April Shaeffer in the Department of Animal Science at NCSU who
managed the data and ran the lab work on the feed samples and
ingredients. Without the help and
cooperation of a lot of folks, this project would not have been possible.
Table 1.
Performance and carcass characteristics of CEFS steers finished on a
control diet with corn and soybean meal, or on diets containing dry corn
gluten feed (DCGF) or wet corn gluten feed (WCGF).
|
Item
|
Angus
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˝ Senepol
|
|
Control
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DCGF
|
WCGF
|
Contrasta
|
|
Number of animals
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40
|
25
|
|
21
|
22
|
22
|
-
|
|
Initial weight, lbs
|
746
|
748
|
|
746
|
746
|
748
|
-
|
|
Final weight, lbs
|
1228
|
1173
|
|
1184
|
1214
|
1201
|
1
|
|
ADG, lb/d
|
3.48
|
3.10
|
|
3.19
|
3.39
|
3.28
|
1
|
|
Dry intake, lb/d
|
22.4
|
20.9
|
|
20.4
|
23.3
|
21.2
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1, 2, 3
|
|
Feed/Gain
|
6.46
|
6.79
|
|
6.46
|
6.91
|
6.51
|
1, 3
|
|
Carcass wt, lb
|
770
|
737
|
|
744
|
763
|
755
|
1
|
|
Yield Grade
|
3.00
|
2.85
|
|
2.89
|
3.00
|
2.89
|
-
|
|
Marbling scoreb
|
6.01
|
5.60
|
|
5.76
|
6.14
|
5.51
|
1, 3
|
|
Quality gradec
|
17.5
|
17.2
|
|
17.3
|
17.8
|
17.0
|
3
|
|
Backfat, inches
|
0.52
|
0.42
|
|
0.47
|
0.50
|
0.45
|
1
|
|
Ribeye area, sq. in.
|
12.7
|
12.3
|
|
12.5
|
12.6
|
12.3
|
-
|
|
Feed cost, $/lb gain
|
0.47
|
0.50
|
|
0.52
|
0.46
|
0.47
|
1, 2
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a Contrasts: 1 =
Angus and ˝ Senepol differ, P < 0.05; 2 = Control and corn gluten feed
rations differ, P < 0.05; 3 = dry corn gluten feed and wet corn gluten
feed differ, P < 0.05.
b Marbling
scores: 4 = slight, 5 = small, 6 =
modest, 7 = moderate.
c USDA Quality
grade: 16 = high select, 17 = low choice, 18 = choice, 19 = high choice.
Figure 2. A and B are
representative of Senepol-sired steers. C and D are representative of
Angus-sired steers.
 
Steer
A Steer C
 
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