The relationship between organic matter digestibility and total digestible nutrients is unestablished for diets containing distillers grains. Three cattle digestion studies were used to evaluate the relationship between total digestible nutrients and digestible organic matter. Results suggest digestible organic matter is consistent relative to total digestible nutrients content for traditional, corn based diets. In finishing and growing diets containing distillers grains additional digestible energy supplied by distillers grains is not accounted for when evaluating only digestible organic matter. Measuring digestible energy content of diets used in digestion trials is essential

Erickson, Galen E.

Gramkow, Jana L.

Hamilton, Hannah C.

Klopfenstein, Terry J.

MacDonald, Jim C., Donald

Watson, Andrea K.

English

DigitalCommons@University of Nebraska

University of Nebraska - LincolnDigitalCommons@University of Nebraska - LincolnNebraska Beef Cattle Reports Animal Science Department2017Relationship between Dietary Total DigestibleNutrients and Digestible Organic Matter in BeefCattle Finishing and Growing Diets With orWithout Distillers GrainsHannah C. HamiltonUniversity of Nebraska-Lincoln, hhamilton6@unl.eduJana L. GramkowUniversity of Nebraska - LincolnJim C. MacDonald DonaldUniversity of Nebraska-Lincoln, jmacdonald2@unl.eduGalen E. EricksonUniversity of Nebraska - Lincoln, gerickson4@unl.eduAndrea K. WatsonUniversity of Nebraska-Lincoln, awatson3@unl.eduSee next page for additional authorsFollow this and additional works at: http://digitalcommons.unl.edu/animalscinbcrPart of the Large or Food Animal and Equine Medicine Commons, Meat Science Commons, andthe Veterinary Preventive Medicine, Epidemiology, and Public Health CommonsThis Article is brought to you for free and open access by the Animal Science Department at DigitalCommons@University of Nebraska - Lincoln. It hasbeen accepted for inclusion in Nebraska Beef Cattle Reports by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln.Hamilton, Hannah C.; Gramkow, Jana L.; MacDonald, Jim C. Donald; Erickson, Galen E.; Watson, Andrea K.; and Klopfenstein,Terry J., "Relationship between Dietary Total Digestible Nutrients and Digestible Organic Matter in Beef Cattle Finishing andGrowing Diets With or Without Distillers Grains" (2017). Nebraska Beef Cattle Reports. 939.http://digitalcommons.unl.edu/animalscinbcr/939AuthorsHannah C. Hamilton, Jana L. Gramkow, Jim C. MacDonald Donald, Galen E. Erickson, Andrea K. Watson,and Terry J. KlopfensteinThis article is available at DigitalCommons@University of Nebraska - Lincoln: http://digitalcommons.unl.edu/animalscinbcr/93976 · 2017 Nebraska Beef Cattle Report©  Th e Board Regents of the University of Nebraska. All rights reserved.stover, solubles, DDG, and supplement. Th e corn stover for this treatment was harvest-ed using a single pass round baler pulled behind the combine. Th e corn residue that was left  was raked into wind rows and baled with a conventional square baler. Th e third experiment used fi ve dietary treatments comparing an 80% DRC- based diet (Corn) with one of two supplemental fat sources (Tallow or Cornoil) to diets with 25.5% distillers solubles (Solubles), or 56% wet DGS (WDGS).RegressionRegression was used to relate digestible OM to TDN. Th e initial model included experiment, animal within experiment, and treatment within experiment. Individual points were used to represent animal within period for each experiment in Figures 2– 4. For Exp. 1 and 2, a combined treatment average was used for each experiment and experiments will be henceforth referred to as 45% HMC and 18% MDGS, respective-ly. Regression models for the relationship between the diff erences in DIGOM, TDN, and GE were developed used treatment average as the observation.ResultsIntercepts for a unifi ed regression model were not signifi cant (P = 0.316). A signifi -cant treatment within experiment eff ect (P < 0.01) resulted in independent regression models for each experiment. An isopleth was indicated with a dotted line to show relative diff erences of slope. Treatments for Exp. 1 were signifi cantly diff erent (P < 0.01) for DIGOM relative to TDN. However, Exp. 1 showed no treatment eff ect for DIGOM. Th erefore, a single slope with a linear rela-tionship was used (Figure 1) and designated as a treatment average (45% HMC) for further analysis. Treatments for Exp. 2 were signifi cantly diff erent (P < 0.01) for DIGOM relative to TDN. However, Exp. 2 showed no treatment eff ect for DIGOM. Th erefore, tent of the feed and feces can be measured using bomb calorimetry to directly measure DE. Th e objective of this study was to com-pare digested organic matter (DIGOM), determined by previous digestibility trials utilizing diets with or without distillers grains, DE, and calculated TDN values using bomb calorimetry.ProcedureTh is study utilized three previously conducted digestion trials where total tract collection and OM analysis of feed and fe-ces were measured to determine OMD. Or-ganic matter digestibility values were then multiplied by dietary OM content to deter-mine digested organic matter (DIGOM, % DM). Dietary DE was calculated from heat of combustion of feed and feces, measured using a bomb calorimeter. Conversion of DE to TDN was assumed to be 2.0 Mcal DE / lb TDN. Regression models were developed using GLM Procedures of SAS. Digestion data were analyzed using the Mixed Procedures of SAS with treatment as a fi xed eff ect and steer as experimental unit. Comparisons were made across and within experiments.Description of ExperimentsTh e fi rst experiment fed a basal diet consisting of 40% Sweet Bran®, 45% high moisture corn (45% HMC), 10% corn silage, and 5% supplement (DM basis) with or without enzyme. Th e second experiment (18% MDGS) had four dietary treatments. Th e negative control (negcontrol) contained 60% untreated corn stover, 18% MDGS, 18% distillers solubles and 4% supplement (DM basis). Th e positive control (poscon-trol) consisted of 60% CaO treated corn stover, 18% MDGS, 18% distillers solubles, and 4% supplement. Th e third treatment (pelletC) was a pellet containing the same proportions of CaO treated corn stover, sol-ubles, MDGS and supplement. Treatment four (pelletS) was also a pellet containing the same proportions of CaO treated corn Hannah C. HamiltonJana L. GramkowJim C. MacDonaldGalen E. EricksonAndrea K. WatsonTerry J. KlopfensteinSummary and ImplicationsTh e relationship between organic matter digestibility and total digestible nutrients is unestablished for diets containing distillers grains. Th ree cattle digestion studies were used to evaluate the relationship between total digestible nutrients and digestible organic matter. Results suggest digestible organic matter is consistent relative to total digestible nutrients content for traditional, corn based diets. In fi nishing and growing diets containing distillers grains additional digestible energy supplied by distillers grains is not accounted for when evaluating only digestible organic matter. Measuring digest-ible energy content of diets used in digestion trials is essential.IntroductionTotal digestible nutrients (TDN) are directly related to digestible energy (DE). Th en, TDN can be converted to DE using 1 lb of TDN equal to 2 Mcal of DE. Previous-ly, TDN was based on proximate analysis, which is no longer commonly used. Th ese analyses were also based on diets contain-ing primarily corn, fat, and alfalfa, but none containing distillers grains. Organic matter digestibility (OMD) is related to TDN and is commonly measured in digestion studies to estimate feeding values. However, the relationship between OMD and TDN is unestablished for diets containing distillers grains. When the amount of wet distillers grains plus solubles (WDGS) is increased in a diet there is an increase in feed effi  ciency but a decrease in OMD. Total energy con- Relationship between Dietary Total Digestible Nutrients and Digestible Organic Matter in Beef Cattle Finishing and Growing Diets With or Without Distillers Grains2017 Nebraska Beef Cattle Report · 77 a single slope with a linear relationship was used (Figure 2) and designated as a treatment average (18% MDGS) for further analysis. In Exp. 3, there was a tendency for a treatment eff ect (P > 0.14). Th erefore treatments were evaluated using separate regression lines (Figure 3) and treatments remained separate for further analysis (Corn, CornOil, Tallow, Solubles, WDGS).Th e diff erence between TDN (% of DM) and DIGOM (% of DM) was greatest for the 18% MDGS (Exp. 2) with 11.1 percent-age units (PPT) diff erence (Table 1). Th e WDGS treatment followed with 10.0 PPT diff erence. Th e solubles, 45% HMC (Exp. 1), and Tallow treatments were 5.9, 3.6, and 0.3 PPT diff erence, respectively. Corn oil and corn treatments had greater DIGOM than TDN showing a PPT diff erence of- 0.4 and- 4.0, respectively.Th ere were no signifi cant diff erences for OM intake (kg) across all treatments (P = 0.88; Table 2). Th ere were no signifi cant diff erences in energy intake (Mcal) across all treatments (P = 0.28). However, OM excreted (kg) was signifi cantly diff erent (P < 0.01), with WDGS and 18%MDGS treatments having the greatest OM excreted, Corn, 45% HMC, Corn Oil and Tallow being intermediate, and solubles having the least OM excreted. Th ere were signifi cant diff erences (P < 0.01) in energy excreted (Mcal) with WDGS and 18% MDGS having the greatest energy excreted, Corn, Corn Oil, Tallow, and 45% HMC being intermediate, and Solubles having the least energy excreted. Th e ratio for consumed energy relative to consumed OM was diff erent across treatments (P < 0.01), with WDGS and 18% MDGS having the greatest ratio, solubles the next greatest ratio, followed by 45% HMC. Corn oil and tallow had the fourth greatest ratio and Corn had the lowest ratio. Th e ratio for excreted OM relative to excreted energy was signifi cantly diff erent (P < 0.01), with solubles and WDGS having the greatest ratio, corn, corn oil, tallow, and 45% HMC being intermediate, and 18% MDGS hav-ing the lowest ratio (Table 2).Th e DIGOM is consistent relative to TDN content of traditional corn based diets. Results from Exp. 2 and 3 with diets contain-ing DGS showed there was some portion of DE that was not accounted for when using only DIGOM. Additional DE is likely due to the protein and fat content of DGS which 95908580757065605555 60 65 70 75 80 85 90 95ControlEnzymeTDN, % DMDIGOM, % DM959085807570656055TDN, % DM55 60 65 70 75 80 85 90 95OMdig, % DMnegcontrolposcontrolpelletCpelletS959085807570656055TDN, % DM55 60 65 70 75 80 85 90 95OMdig, % DMTallowWDGSCorn OilCornSolublesFigure 1. TDN vs DIGOM in 2 fi nishing diets without DGS (Exp. 1). Control (diamonds) and enzyme (squares) data are shown in the graph where individual data points indicate animal as the experimental unit. Th e regression equation for the data was TDN = [0.967 (±0.106) × DIGOM] + 6.16 (±8.20) % (R2 =0.892).Figure 3. TDN vs DIGOM in 5 fi nishing diets (Exp. 3). Tallow (circles), WDGS (squares), Corn Oil (triangles), Corn (exes), and Solubles (asterisks) data are shown in the graph where individual data points indicate animal as the experimental unit. Th e regression equation for the Tallow treatment was TDN = [0.990 (±0.0433) × DIGOM] + 1.09(±3.44) % (R2 =0.994). Th e regression equation for the WDGS treatment was TDN = [1.15 (±0.0471) × DIGOM]- 0.887(±3.49) % (R2 =0.995). Th e regression equation for the Corn Oil treatment was TDN = [1.10 (±0.0712) × DIGOM]- 7.70(±5.44) % (R2 =0.987). Th e regression equation for the Corn treatment was TDN = [1.11 (±0.0519) × DIGOM]- 12.5(±4.12) % (r2 =0.993). Th e regression equation for the Solubles treatment was TDN = [1.24 (±0.0833) × DIGOM]- 13.9(±6.72) % (R2 =0.987).Figure 2. TDN vs DIGOM of growing diets with DGS (Exp. 2). NEGCONTROL (diamond), POSCONTROL (square), pelletC (triangle), and pelletS (exes) data are shown in the graph where individual data points indicate animal as the experimental unit. Th e regression equation for the data was TDN = [1.10 (±0.0786) × DIGOM] + 4.59 (±5.14) % (R2 =0.852).78 · 2017 Nebraska Beef Cattle Reportsupplies additional energy relative to OM content. All treatments consumed the same amount of OM but varied in energy intake. Th is was more apparent when expressed as a ratio with energy intake. Th e average of all treatments in Exp. 2 had the greatest ratio for energy intake relative to OM intake. Conversely, the average of all treatments had the smallest ratio for energy excreted relative to OM excreted. Th ese data suggest that there is more energy being consumed but not being excreted in the feces. Th e fi ber content of DGS could reduce energy supplied, but would remain in feces as OM, which is why greater OM was excreted from treatments containing DGS.ConclusionsTh e diff erence between TDN and DIGOM is much greater for diets con-taining DGS. When the percent diff erence between TDN and DIGOM is expressed in terms of GE within an individual experi-ment, the relationship becomes uniform across diets. Th erefore, it is essential to measure digestible energy content of diets in digestion trials, especially diets includ-ing distillers grains.Hannah Hamilton, research technicianJana L. Harding, research technicianJim C. MacDonald, associate professorTerry J. Klopfenstein, professor, Animal science, LincolnTable 1. Average TDN and DIGOM for treatments for experiments 1– 3.Treatments1 TDN2, % of DM DIGOM2, % of DM Diff erence3Exp. 145% HMC 80.5 76.9 3.6Exp. 218% MDGS 76.4 65.3 11.1Exp. 3Corn 75.2 79.2 - 4.0CornOil 75.9 76.2 - 0.4Tallow 79.7 79.3 0.3Solubles 86.6 80.7 5.9WDGS4 83.7 73.8 10.01Treatments from Exp. 1; Contains control and enzyme treatments which both contain 45% HMC; HMC: High moisture corn; Treatments from Exp. 2; Contains poscontrol, negcontrol, pelletS and pellet which all contain 18% MDGS; MDGS: Modifi ed distillers grains; Treatments from Exp. 3; WDGS: Wet distillers grains2Treatment average across animal and period; TDN: Total digestible nutrients; DIGOM: Digested organic matter3 Percentage unit diff erence4 56% inclusion (DM basis) of WDGS in the dietTable 2. Diff erence in diet and fecal energy relative to OM1 content for all experiment treatments.TreatmentCorn 45% HMC2Corn OilTallow Solubles WDGS3 18% MDGS4SEM P- ValueConsumedOM, lb 10.7 9.53 9.34 10.0 9.34 10.0 9.93 0.84 0.88Energy, Mcal46.4 44.9 42.7 45.6 45.1 51.0 50.9 4.23 0.28ExcretedOM, lb 1.92bc 1.80bc 2.01bc 1.87bc 1.35c 2.32ab 2.71a 0.30 <0.01Energy, Mcal9.61bc 9.17bc 10.5bc 9.58bc 7.30c 12.4ab 13.5a 1.49 <0.01Energy, Mcal/lb OM 5Con-sumed4.32e 4.72c 4.56d 4.56d 4.83b 5.07a 5.11a 0.025 <0.01Excreted 5.00bc 5.11bc 5.25ab 5.18abc 5.40a 5.36a 5.00c 0.087 <0.011 OM: Organic matter2Treatment average for Exp. 1; Contains control and enzyme treatments which both contain 45% HMC; HMC: High moisture corn3 56% inclusion (DM basis) of WDGS in the diet4 Treatment average for Exp. 2; Contains poscontrol, negcontrol, pelletS and pelletC which all contain 18% MDGS; MDGS: Modifi ed distillers grains5 Consumed: Consumed energy (Mcal) was divided by consumed OM (lb). Excreted: Excreted energy (Mcal) was divided by consumed OM (lb).

Relationship between Dietary Total Digestible Nutrients and Digestible Organic Matter in Beef Cattle Finishing and Growing Diets With or Without Distillers Grains

UNL | Libraries

University of Nebraska - Lincoln
DigitalCommons@University of Nebraska - Lincoln
Nebraska Beef Cattle Reports Animal Science Department
2017
Relationship between Dietary Total Digestible
Nutrients and Digestible Organic Matter in Beef
Cattle Finishing and Growing Diets With or
Without Distillers Grains
Hannah C. Hamilton
University of Nebraska-Lincoln, hhamilton6@unl.edu
Jana L. Gramkow
University of Nebraska - Lincoln
Jim C. MacDonald Donald
University of Nebraska-Lincoln, jmacdonald2@unl.edu
Galen E. Erickson
University of Nebraska - Lincoln, gerickson4@unl.edu
Andrea K. Watson
University of Nebraska-Lincoln, awatson3@unl.edu
See next page for additional authorsFollow this and additional works at: http://digitalcommons.unl.edu/animalscinbcr
Part of the Large or Food Animal and Equine Medicine Commons, Meat Science Commons, and
the Veterinary Preventive Medicine, Epidemiology, and Public Health Commons
This Article is brought to you for free and open access by the Animal Science Department at DigitalCommons@University of Nebraska - Lincoln. It has
been accepted for inclusion in Nebraska Beef Cattle Reports by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln.
Hamilton, Hannah C.; Gramkow, Jana L.; MacDonald, Jim C. Donald; Erickson, Galen E.; Watson, Andrea K.; and Klopfenstein,
Terry J., "Relationship between Dietary Total Digestible Nutrients and Digestible Organic Matter in Beef Cattle Finishing and
Growing Diets With or Without Distillers Grains" (2017). Nebraska Beef Cattle Reports. 939.
http://digitalcommons.unl.edu/animalscinbcr/939
Authors
Hannah C. Hamilton, Jana L. Gramkow, Jim C. MacDonald Donald, Galen E. Erickson, Andrea K. Watson,
and Terry J. Klopfenstein
This article is available at DigitalCommons@University of Nebraska - Lincoln: http://digitalcommons.unl.edu/animalscinbcr/939
76 · 2017 Nebraska Beef Cattle Report
©  Th e Board Regents of the University of 
Nebraska. All rights reserved.
stover, solubles, DDG, and supplement. Th e 
corn stover for this treatment was harvest-
ed using a single pass round baler pulled 
behind the combine. Th e corn residue that 
was left  was raked into wind rows and baled 
with a conventional square baler. Th e third 
experiment used fi ve dietary treatments 
comparing an 80% DRC- based diet (Corn) 
with one of two supplemental fat sources 
(Tallow or Cornoil) to diets with 25.5% 
distillers solubles (Solubles), or 56% wet 
DGS (WDGS).
Regression
Regression was used to relate digestible 
OM to TDN. Th e initial model included 
experiment, animal within experiment, and 
treatment within experiment. Individual 
points were used to represent animal within 
period for each experiment in Figures 2– 4. 
For Exp. 1 and 2, a combined treatment 
average was used for each experiment and 
experiments will be henceforth referred to 
as 45% HMC and 18% MDGS, respective-
ly. Regression models for the relationship 
between the diff erences in DIGOM, TDN, 
and GE were developed used treatment 
average as the observation.
Results
Intercepts for a unifi ed regression model 
were not signifi cant (P = 0.316). A signifi -
cant treatment within experiment eff ect (P 
< 0.01) resulted in independent regression 
models for each experiment. An isopleth 
was indicated with a dotted line to show 
relative diff erences of slope. Treatments for 
Exp. 1 were signifi cantly diff erent (P < 0.01) 
for DIGOM relative to TDN. However, Exp. 
1 showed no treatment eff ect for DIGOM. 
Th erefore, a single slope with a linear rela-
tionship was used (Figure 1) and designated 
as a treatment average (45% HMC) for 
further analysis. Treatments for Exp. 2 were 
signifi cantly diff erent (P < 0.01) for DIGOM 
relative to TDN. However, Exp. 2 showed 
no treatment eff ect for DIGOM. Th erefore, 
tent of the feed and feces can be measured 
using bomb calorimetry to directly measure 
DE. Th e objective of this study was to com-
pare digested organic matter (DIGOM), 
determined by previous digestibility trials 
utilizing diets with or without distillers 
grains, DE, and calculated TDN values 
using bomb calorimetry.
Procedure
Th is study utilized three previously 
conducted digestion trials where total tract 
collection and OM analysis of feed and fe-
ces were measured to determine OMD. Or-
ganic matter digestibility values were then 
multiplied by dietary OM content to deter-
mine digested organic matter (DIGOM, % 
DM). Dietary DE was calculated from heat 
of combustion of feed and feces, measured 
using a bomb calorimeter. Conversion of 
DE to TDN was assumed to be 2.0 Mcal 
DE / lb TDN. Regression models were 
developed using GLM Procedures of SAS. 
Digestion data were analyzed using the 
Mixed Procedures of SAS with treatment as 
a fi xed eff ect and steer as experimental unit. 
Comparisons were made across and within 
experiments.
Description of Experiments
Th e fi rst experiment fed a basal diet 
consisting of 40% Sweet Bran®, 45% high 
moisture corn (45% HMC), 10% corn 
silage, and 5% supplement (DM basis) with 
or without enzyme. Th e second experiment 
(18% MDGS) had four dietary treatments. 
Th e negative control (negcontrol) contained 
60% untreated corn stover, 18% MDGS, 
18% distillers solubles and 4% supplement 
(DM basis). Th e positive control (poscon-
trol) consisted of 60% CaO treated corn 
stover, 18% MDGS, 18% distillers solubles, 
and 4% supplement. Th e third treatment 
(pelletC) was a pellet containing the same 
proportions of CaO treated corn stover, sol-
ubles, MDGS and supplement. Treatment 
four (pelletS) was also a pellet containing 
the same proportions of CaO treated corn 
Hannah C. Hamilton
Jana L. Gramkow
Jim C. MacDonald
Galen E. Erickson
Andrea K. Watson
Terry J. Klopfenstein
Summary and Implications
Th e relationship between organic matter 
digestibility and total digestible nutrients is 
unestablished for diets containing distillers 
grains. Th ree cattle digestion studies were 
used to evaluate the relationship between 
total digestible nutrients and digestible 
organic matter. Results suggest digestible 
organic matter is consistent relative to total 
digestible nutrients content for traditional, 
corn based diets. In fi nishing and growing 
diets containing distillers grains additional 
digestible energy supplied by distillers grains 
is not accounted for when evaluating only 
digestible organic matter. Measuring digest-
ible energy content of diets used in digestion 
trials is essential.
Introduction
Total digestible nutrients (TDN) are 
directly related to digestible energy (DE). 
Th en, TDN can be converted to DE using 1 
lb of TDN equal to 2 Mcal of DE. Previous-
ly, TDN was based on proximate analysis, 
which is no longer commonly used. Th ese 
analyses were also based on diets contain-
ing primarily corn, fat, and alfalfa, but none 
containing distillers grains. Organic matter 
digestibility (OMD) is related to TDN and 
is commonly measured in digestion studies 
to estimate feeding values. However, the 
relationship between OMD and TDN is 
unestablished for diets containing distillers 
grains. When the amount of wet distillers 
grains plus solubles (WDGS) is increased in 
a diet there is an increase in feed effi  ciency 
but a decrease in OMD. Total energy con-
 Relationship between Dietary Total Digestible Nutrients and 
Digestible Organic Matter in Beef Cattle Finishing and 
Growing Diets With or Without Distillers Grains
2017 Nebraska Beef Cattle Report · 77 
a single slope with a linear relationship 
was used (Figure 2) and designated as a 
treatment average (18% MDGS) for further 
analysis. In Exp. 3, there was a tendency 
for a treatment eff ect (P > 0.14). Th erefore 
treatments were evaluated using separate 
regression lines (Figure 3) and treatments 
remained separate for further analysis 
(Corn, CornOil, Tallow, Solubles, WDGS).
Th e diff erence between TDN (% of DM) 
and DIGOM (% of DM) was greatest for the 
18% MDGS (Exp. 2) with 11.1 percent-
age units (PPT) diff erence (Table 1). Th e 
WDGS treatment followed with 10.0 PPT 
diff erence. Th e solubles, 45% HMC (Exp. 
1), and Tallow treatments were 5.9, 3.6, and 
0.3 PPT diff erence, respectively. Corn oil 
and corn treatments had greater DIGOM 
than TDN showing a PPT diff erence of- 0.4 
and- 4.0, respectively.
Th ere were no signifi cant diff erences 
for OM intake (kg) across all treatments (P 
= 0.88; Table 2). Th ere were no signifi cant 
diff erences in energy intake (Mcal) across 
all treatments (P = 0.28). However, OM 
excreted (kg) was signifi cantly diff erent 
(P < 0.01), with WDGS and 18%MDGS 
treatments having the greatest OM 
excreted, Corn, 45% HMC, Corn Oil and 
Tallow being intermediate, and solubles 
having the least OM excreted. Th ere 
were signifi cant diff erences (P < 0.01) in 
energy excreted (Mcal) with WDGS and 
18% MDGS having the greatest energy 
excreted, Corn, Corn Oil, Tallow, and 45% 
HMC being intermediate, and Solubles 
having the least energy excreted. Th e ratio 
for consumed energy relative to consumed 
OM was diff erent across treatments (P < 
0.01), with WDGS and 18% MDGS having 
the greatest ratio, solubles the next greatest 
ratio, followed by 45% HMC. Corn oil and 
tallow had the fourth greatest ratio and 
Corn had the lowest ratio. Th e ratio for 
excreted OM relative to excreted energy 
was signifi cantly diff erent (P < 0.01), with 
solubles and WDGS having the greatest 
ratio, corn, corn oil, tallow, and 45% HMC 
being intermediate, and 18% MDGS hav-
ing the lowest ratio (Table 2).
Th e DIGOM is consistent relative to 
TDN content of traditional corn based diets. 
Results from Exp. 2 and 3 with diets contain-
ing DGS showed there was some portion of 
DE that was not accounted for when using 
only DIGOM. Additional DE is likely due 
to the protein and fat content of DGS which 
95
90
85
80
75
70
65
60
55
55 60 65 70 75 80 85 90 95
Control
EnzymeTD
N
, %
 D
M
DIGOM, % DM
95
90
85
80
75
70
65
60
55
TD
N
, %
 D
M
55 60 65 70 75 80 85 90 95
OMdig, % DM
negcontrol
poscontrol
pelletC
pelletS
95
90
85
80
75
70
65
60
55
TD
N
, %
 D
M
55 60 65 70 75 80 85 90 95
OMdig, % DM
Tallow
WDGS
Corn Oil
Corn
Solubles
Figure 1. TDN vs DIGOM in 2 fi nishing diets without DGS (Exp. 1). Control (diamonds) and enzyme 
(squares) data are shown in the graph where individual data points indicate animal as the experimental 
unit. Th e regression equation for the data was TDN = [0.967 (±0.106) × DIGOM] + 6.16 (±8.20) % 
(R2 =0.892).
Figure 3. TDN vs DIGOM in 5 fi nishing diets (Exp. 3). Tallow (circles), WDGS (squares), Corn Oil 
(triangles), Corn (exes), and Solubles (asterisks) data are shown in the graph where individual data 
points indicate animal as the experimental unit. Th e regression equation for the Tallow treatment was 
TDN = [0.990 (±0.0433) × DIGOM] + 1.09(±3.44) % (R2 =0.994). Th e regression equation for the 
WDGS treatment was TDN = [1.15 (±0.0471) × DIGOM]- 0.887(±3.49) % (R2 =0.995). Th e regression 
equation for the Corn Oil treatment was TDN = [1.10 (±0.0712) × DIGOM]- 7.70(±5.44) % (R2 =0.987). 
Th e regression equation for the Corn treatment was TDN = [1.11 (±0.0519) × DIGOM]- 12.5(±4.12) % 
(r2 =0.993). Th e regression equation for the Solubles treatment was TDN = [1.24 (±0.0833) × 
DIGOM]- 13.9(±6.72) % (R2 =0.987).
Figure 2. TDN vs DIGOM of growing diets with DGS (Exp. 2). NEGCONTROL (diamond), 
POSCONTROL (square), pelletC (triangle), and pelletS (exes) data are shown in the graph where 
individual data points indicate animal as the experimental unit. Th e regression equation for the 
data was TDN = [1.10 (±0.0786) × DIGOM] + 4.59 (±5.14) % (R2 =0.852).
78 · 2017 Nebraska Beef Cattle Report
supplies additional energy relative to OM 
content. All treatments consumed the same 
amount of OM but varied in energy intake. 
Th is was more apparent when expressed as 
a ratio with energy intake. Th e average of all 
treatments in Exp. 2 had the greatest ratio 
for energy intake relative to OM intake. 
Conversely, the average of all treatments 
had the smallest ratio for energy excreted 
relative to OM excreted. Th ese data suggest 
that there is more energy being consumed 
but not being excreted in the feces. Th e 
fi ber content of DGS could reduce energy 
supplied, but would remain in feces as OM, 
which is why greater OM was excreted from 
treatments containing DGS.
Conclusions
Th e diff erence between TDN and 
DIGOM is much greater for diets con-
taining DGS. When the percent diff erence 
between TDN and DIGOM is expressed in 
terms of GE within an individual experi-
ment, the relationship becomes uniform 
across diets. Th erefore, it is essential to 
measure digestible energy content of diets 
in digestion trials, especially diets includ-
ing distillers grains.
Hannah Hamilton, research technician
Jana L. Harding, research technician
Jim C. MacDonald, associate professor
Terry J. Klopfenstein, professor, Animal 
science, Lincoln
Table 1. Average TDN and DIGOM for treatments for experiments 1– 3.
Treatments1 TDN2, % of DM DIGOM2, % of DM Diff erence3
Exp. 1
45% HMC 80.5 76.9 3.6
Exp. 2
18% MDGS 76.4 65.3 11.1
Exp. 3
Corn 75.2 79.2 - 4.0
CornOil 75.9 76.2 - 0.4
Tallow 79.7 79.3 0.3
Solubles 86.6 80.7 5.9
WDGS4 83.7 73.8 10.0
1Treatments from Exp. 1; Contains control and enzyme treatments which both contain 45% HMC; HMC: High moisture corn; 
Treatments from Exp. 2; Contains poscontrol, negcontrol, pelletS and pellet which all contain 18% MDGS; MDGS: Modifi ed 
distillers grains; Treatments from Exp. 3; WDGS: Wet distillers grains
2Treatment average across animal and period; TDN: Total digestible nutrients; DIGOM: Digested organic matter
3 Percentage unit diff erence
4 56% inclusion (DM basis) of WDGS in the diet
Table 2. Diff erence in diet and fecal energy relative to OM1 content for all experiment treatments.
Treatment
Corn 45% 
HMC2
Corn 
Oil
Tallow Solubles WDGS3 18% 
MDGS4
SEM P- 
Value
Consumed
OM, lb 10.7 9.53 9.34 10.0 9.34 10.0 9.93 0.84 0.88
Energy, 
Mcal
46.4 44.9 42.7 45.6 45.1 51.0 50.9 4.23 0.28
Excreted
OM, lb 1.92bc 1.80bc 2.01bc 1.87bc 1.35c 2.32ab 2.71a 0.30 <0.01
Energy, 
Mcal
9.61bc 9.17bc 10.5bc 9.58bc 7.30c 12.4ab 13.5a 1.49 <0.01
Energy, 
Mcal/lb 
OM 5
Con-
sumed
4.32e 4.72c 4.56d 4.56d 4.83b 5.07a 5.11a 0.025 <0.01
Excreted 5.00bc 5.11bc 5.25ab 5.18abc 5.40a 5.36a 5.00c 0.087 <0.01
1 OM: Organic matter
2Treatment average for Exp. 1; Contains control and enzyme treatments which both contain 45% HMC; HMC: High moisture 
corn
3 56% inclusion (DM basis) of WDGS in the diet
4 Treatment average for Exp. 2; Contains poscontrol, negcontrol, pelletS and pelletC which all contain 18% MDGS; MDGS: 
Modifi ed distillers grains
5 Consumed: Consumed energy (Mcal) was divided by consumed OM (lb). Excreted: Excreted energy (Mcal) was divided by 
consumed OM (lb).


https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1957&context=animalscinbcr

Relationship between Dietary Total Digestible Nutrients and Digestible Organic Matter in Beef Cattle Finishing and Growing Diets With or Without Distillers Grains

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