An experiment was conducted to evaluate the effect of supplemental urea in dry rolled corn based finishing diets containing low inclusions of distillers grains. Treatments were set up in a 3 × 3 factorial arrangement. The first factor was wet distillers inclusion at either 10, 15, or 20% of diet DM. The second factor was urea inclusion at either 0, 0.5, or 1.0% of diet dry matter. Increasing inclusion of distillers linearly improved feed conversion and linearly reduced dry matter intake. An interaction for feed efficiency was observed where there was no effect of added urea when 10% or 20% distillers was fed and a quadratic effect was observed when 15% distillers grains was fed where 0.5% urea appeared to be optimum. Added urea in a finishing diet with 20 or 10% distillers has minimal impact on finishing performance; however, feeding 0.5% urea in a 15% distillers diet may be beneficial

Boyd, Bradley M.

Erickson, Galen E.

Luebbe, Matthew K.

MacDonald, James C.

English

UNL | Libraries

University of Nebraska - Lincoln
DigitalCommons@University of Nebraska - Lincoln
Nebraska Beef Cattle Reports Animal Science Department
2019
Effects of Urea and Distillers Inclusion in Finishing
Diets on Steer Performance and Carcass
Characteristics
Bradley M. Boyd
University of Nebraska-Lincoln, bboyd4@unl.edu
James C. MacDonald
University of Nebraska - Lincoln, jmacdonald2@unl.edu
Matthew K. Luebbe
mluebbe2@unl.edu
Galen E. Erickson
University of Nebraska - Lincoln, gerickson4@unl.edu
Follow 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.
Boyd, Bradley M.; MacDonald, James C.; Luebbe, Matthew K.; and Erickson, Galen E., "Effects of Urea and Distillers Inclusion in
Finishing Diets on Steer Performance and Carcass Characteristics" (2019). Nebraska Beef Cattle Reports. 1018.
http://digitalcommons.unl.edu/animalscinbcr/1018
2019 Nebraska Beef Cattle Report · 97 
©  The Board Regents of the University of  
Nebraska. All rights reserved.
the morning prior to feeding. These same 
three animals were used for both blood col-
lections. The first blood collection was on 
d 28 of the finishing period after all cattle 
had been fully adapted onto their respective 
finishing diet. The second blood collection 
was on d 92 of the finishing period.
Cattle were implanted with a TE- IS 
(Elanco Animal Health) on d 28 and 
reimplanted with a TE- S (Elanco Animal 
Health) on d 90 of the finishing period. 
The Heavy block was on feed for 153 days 
and the light and mid blocks were on feed 
for 167 days. Cattle were slaughtered at a 
commercial abattoir (Cargill Meat Solu-
tions, Fort Morgan, CO) and carcass data 
collected.
Data were analyzed using the mixed 
procedure of SAS for performance, car-
cass and blood variables with block and 
treatment as fixed effects. Blood data were 
analyzed as a repeated measure over time. 
Due to missing carcass data on the heavy 
block, data from that block were omitted 
from the carcass and carcass adjusted 
analysis of performance leaving 36 pens 
with 4 replications per treatment for these 
observations.
Results
Performance data are presented in Table 
2. There were no significant interactions 
between distillers and urea inclusion (P 
≥ 0.11) with the exception of F:G so only 
the main effects are presented. There was 
a significant quadratic interaction (P = 
0.05) between distillers and urea inclu-
sion for carcass adjusted F:G (Figure 1). 
At 10% distillers, F:G appears to remain 
consistent as urea is increased in the diet. 
When feeding 15% distillers added urea 
appears to have a quadratic effect on F:G 
with lower F:G at 0.5% urea inclusion. For 
20% distillers in the diet adding urea at 
0.5% of the diet appears to have a negative 
impact on F:G while1.0% urea resulted in 
similar performance to the 0 urea control. 
This interaction would suggest that when 
Effects of Urea and Distillers Inclusion in Finishing Diets  
on Steer Performance and Carcass Characteristics
Bradley M. Boyd
James C. MacDonald
Matthew K. Luebbe
Galen E. Erickson
Summary with Implications
An experiment was conducted to evaluate 
the effect of supplemental urea in dry rolled 
corn based finishing diets containing low 
inclusions of distillers grains. Treatments 
were set up in a 3 × 3 factorial arrangement. 
The first factor was wet distillers inclusion at 
either 10, 15, or 20% of diet DM. The second 
factor was urea inclusion at either 0, 0.5, or 
1.0% of diet dry matter. Increasing inclusion 
of distillers linearly improved feed conversion 
and linearly reduced dry matter intake. An 
interaction for feed efficiency was observed 
where there was no effect of added urea when 
10% or 20% distillers was fed and a quadrat-
ic effect was observed when 15% distillers 
grains was fed where 0.5% urea appeared to 
be optimum. Added urea in a finishing diet 
with 20 or 10% distillers has minimal impact 
on finishing performance; however, feeding 
0.5% urea in a 15% distillers diet may be 
beneficial.
Introduction
Distillers grains are a good source of 
protein containing around 30% CP with 
63% of this CP being rumen ungradable 
protein. With inclusions of distillers grains 
in finishing diets being greater than 25% 
over the past 10 years, protein has been 
over fed; therefore, meeting protein re-
quirements (RDP and MP) hasn’t been an 
issue. Previous research would suggest that 
when feeding distillers grains in dry rolled 
corn (DRC) based diets at greater than 25% 
of diet DM, no additional urea supple-
mentation is needed to maintain animal 
performance. However, with increasing 
distillers grain price, inclusion of distillers 
has decreased to a level where adding sup-
plemental urea may be beneficial. A recent 
survey suggested that, in the Midwest, the 
average inclusion of distillers in commer-
cial feedlots is 19.9% of diet DM. Previous 
research has evaluated feeding 10 or 20% 
dry distillers with or without urea and they 
observed no performance response with 
added urea. However, there was a numer-
ical improvement in feed conversion in 
the 10% distillers diet (2005 Nebraska Beef 
Cattle Report, pp 42– 44).
With limited research on the topic, the 
objective of this research was to determine 
the effects of supplementing urea in dry 
rolled corn based finishing diets containing 
low inclusions of distillers grains.
Procedure
Four hundred and thirty two cross-
breed steers were utilized in a study at the 
Panhandle Research and Extension Center 
near Scottsbluff NE. Treatments were set up 
in a 3×3 factorial arrangement with factors 
consisting of three distillers inclusions (10, 
15, or 20% of the diet DM) and three urea 
inclusions (0, 0.5, or 1.0% of diet DM). 
Diets were dry- rolled corn (DRC) based 
using corn silage as the roughage source 
(Table 1). A liquid supplement was utilized 
and contained either 0 or 1% urea and the 
0.5% urea treatment was accomplished by 
mixing a 50:50 blend of the 2 supplements. 
Cattle were fed once daily in the morning 
and managed on a slick bunk protocol. 
Rumensin (Elanco Animal Health) was 
supplied to the cattle at 360 mg/hd/d and 
Tylan (Elanco Animal Health) was supplied 
at 90 mg/hd/d added to the diet using a mi-
cro machine (Animal Health International). 
Three blocks were used with one replication 
in the light block, three replications in the 
middle block, and two replications in the 
heavy block. This design totaled 54 pens 
with 6 replications per treatment.
Blood was collected twice during the 
finishing period for plasma urea nitrogen 
(PUN) analysis. Blood was collected from 
three randomly selected animals per pen in 
98 · 2019 Nebraska Beef Cattle Report
mg/100 mL to be necessary for optimum 
performance to be maintained. The values 
for the current trial are more than double 
(> 17.8) this value suggesting that there was 
more than enough excess nitrogen in the 
blood to maintain performance across all 
treatments.
Conclusion
Based on these results, when feeding 10 
or 20% distillers grains in a finishing diet 
added urea is of limited benefit for animal 
performance. However, when feeding 15% 
distillers grains in the diet adding 0.5% urea 
to the diet appears to improve feed efficien-
cy. However, it is difficult to explain the 
variation across 10, 15, and 20% inclusion. 
Our conclusion is that urea supplementa-
tion was unnecessary. Increasing inclusion 
of distillers grains in the diet even from 10 
to 20% improved gain and reduced intake, 
thereby improving feed conversion.
Bradley M. Boyd, graduate student
James MacDonald, professor, University of 
Nebraska– Lincoln, Lincoln NE
Matthew Luebbe, associate professor, 
University of Nebraska– Lincoln, Scottsbluff 
NE
Galen E. Erickson, professor, University of 
Nebraska– Lincoln Department of Animal 
Science, Lincoln NE
not significant (P = 0.26) F:G appears to be 
quadratic with a plateau appearing at 0.5% 
urea. There was no difference (P = 0.49) in 
DMI observed for increasing urea levels. 
Average daily gain and final live weight 
increased linearly (P < 0.03) as distillers 
grains increased in the diet; however, ADG 
and final live weight tended to have a qua-
dratic response (P < 0.09) with increasing 
levels of urea in the diet with maximum 
values at 0.5% inclusion.
For carcass adjusted performance, a 
tendency for a linear increase (P ≤ 0.08) 
in final BW and ADG was observed for 
increasing levels of distillers grains. Both 
DMI and F:G linearly decreased (P < 0.01) 
as distillers grains was increased in the diet. 
Additionally F:G was linearly decreased (P 
= 0.02) with the addition of urea in the diet 
however, no other measures were signifi-
cantly (P ≥ 0.14) affected by urea inclusion.
A tendency for a linear increase (P = 
0.08) in HCW was observed with increas-
ing levels of distillers grains in the diet. 
Additionally, a linear increase (P < 0.01) 
in 12th rib fat thickness was observed 
with increasing levels of distillers grains 
in the diet. However, there were no other 
significant (P ≥ 0.15) differences for carcass 
characteristic for either distillers or urea 
inclusion in the diet. Plasma urea nitrogen 
linearly increased (P < 0.01) for both added 
distillers and added urea in the diet. Others 
have found a minimum BUN value of 7 
feeding 10 or 20% distillers grains added 
urea in the diet has minimal benefit on per-
formance but when feeding 15% distillers 
grains some added urea may be beneficial. 
However, with this type of interaction it is 
difficult to make conclusions and determine 
if the interaction is real or due to random 
variation in the data. Additionally, the 
missing carcass data from the heavy block 
of cattle may have had an effect on the data. 
A depression in animal performance for 
20% distillers and 0.5% urea inclusion is the 
primary cause for the interaction, which is 
difficult to explain biologically.
The remaining performance variables 
were analyzed for main effects. For live per-
formance, DMI and F:G decreased linearly 
(P < 0.01) with increasing inclusion of dis-
tillers grains. Additionally, a linear decrease 
(P = 0.05) in F:G was observed for increas-
ing levels of urea in the diet. Visually, while 
Table 1. Diet ingredient composition as % of diet DM by treatment
Ingredient
10% Distillers 15% Distillers 20% Distillers
0 0.5 1.0 0 0.5 1.0 0 0.5 1.0
DRC, % DM 69 69 69 64 64 64 59 59 59
WDGS, % DM 10 10 10 15 15 15 20 20 20
Corn Silage, % DM 15 15 15 15 15 15 15 15 15
Supplement1 , % DM 6 5.5 5 6 5.5 5 6 5.5 5
Urea, % DM 0 0.5 1.0 0 0.5 1.0 0 0.5 1.0
Crude Protein, % 10.8 12.2 13.6 12.0 13.4 14.7 13.1 14.5 15.9
Initial MP Balance2, g/d - 105 - 47 8 - 41 14 28 - 6 94 39
Initial RDP Balance, g/d - 196 - 54 86 - 158 - 19 118 - 118 16 147
Midpoint MP Balance2, g/d - 51 15 70 17 86 95 67 168 115
Midpoint RDP Balance, g/d - 210 - 58 94 - 170 - 21 126 - 127 17 158
1 Micro machine was used to add 360 mg of Rumensin and 90 mg per steer of Tylan to the diet daily.
2 Metabolizable Protein balance calculated using 1996 NRC Model to predict MP supply corrected for RDP balance deficiency if one existed (MP balance- (RDP balance*.64)). Initial MP balance is 
calculated for the end of the step up period and midpoint MP balance was calculated for the middle of the finishing period.
Figure 1. Carcass adjusted F:G interaction 
distillers level and urea inclusion.
2019 Nebraska Beef Cattle Report · 99 
Table 2. Main effects of distillers inclusion and urea inclusion on performance
Measure
Distillers, % diet DM
SEM
P- Value Urea, % Diet DM
SEM
P- Value
10 15 20 Lin Quad 0% 0.5% 1.0% Lin Quad
Live Performance
Initial BW, lb 617 616 615 1 0.06 0.94 617 616 616 1 0.22 0.75
Final BW, lb 1328 1337 1345 6 0.03 0.94 1328 1344 1338 6 0.19 0.09
ADG, lb/d 4.39 4.45 4.50 0.03 0.01 0.96 4.39 4.49 4.46 0.03 0.16 0.08
DMI, lb/d 24.1 24.0 23.4 0.2 <0.01 0.16 23.9 23.9 23.7 0.2 0.49 0.61
F:G 5.49 5.40 5.18 0.002 <0.01 0.25 5.43 5.32 5.32 0.002 0.05 0.26
Carcass Adjusted Performance
Initial BW, lb 583 582 581 1 0.09 0.99 582 583 581 1 0.43 0.25
Final BW, lb 1277 1293 1298 8 0.08 0.63 1277 1298 1293 8 0.15 0.18
ADG, lb/d 4.16 4.25 4.29 0.05 0.06 0.65 4.16 4.28 4.26 0.05 0.14 0.24
DMI, lb/d 23.5 23.2 22.6 0.2 <0.01 0.55 23.2 23.3 23.0 0.2 0.45 0.46
F:G 5.65 5.46 5.26 0.002 <0.01 0.93 5.56 5.43 5.38 0.002 0.02 0.50
Carcass Characteristics
HCW, lb 805 815 818 5 0.08 0.62 805 818 815 5 0.15 0.18
Dressing % 62.1 62.5 62.4 0.2 0.19 0.19 62.3 62.2 62.4 0.2 0.81 0.59
LM Area, in2 13.7 14.0 13.8 0.2 0.43 0.24 13.8 13.8 13.9 0.2 0.74 0.63
12th Rib Fat, in 0.50 0.52 0.56 0.02 <0.01 0.84 0.53 0.52 0.52 0.02 0.75 0.89
Marbling 447 456 440 7 0.45 0.12 447 448 449 7 0.82 0.97
USDA Yield Grade 2.9 2.9 3.1 0.1 0.14 0.39 3.0 3.0 3.0 0.1 0.99 0.52
PUN mg/100mL1 18.57 20.03 22.72 0.53 <0.01 0.33 17.81 20.31 23.20 0.50 <0.01 0.73
1 PUN = Plasma Urea Nitrogen


Effects of Urea and Distillers Inclusion in Finishing Diets
on Steer Performance and Carcass Characteristics

DigitalCommons@University of Nebraska

University of Nebraska - LincolnDigitalCommons@University of Nebraska - LincolnNebraska Beef Cattle Reports Animal Science Department2019Effects of Urea and Distillers Inclusion in FinishingDiets on Steer Performance and CarcassCharacteristicsBradley M. BoydUniversity of Nebraska-Lincoln, bboyd4@unl.eduJames C. MacDonaldUniversity of Nebraska - Lincoln, jmacdonald2@unl.eduMatthew K. Luebbemluebbe2@unl.eduGalen E. EricksonUniversity of Nebraska - Lincoln, gerickson4@unl.eduFollow 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.Boyd, Bradley M.; MacDonald, James C.; Luebbe, Matthew K.; and Erickson, Galen E., "Effects of Urea and Distillers Inclusion inFinishing Diets on Steer Performance and Carcass Characteristics" (2019). Nebraska Beef Cattle Reports. 1018.http://digitalcommons.unl.edu/animalscinbcr/10182019 Nebraska Beef Cattle Report · 97 ©  The Board Regents of the University of  Nebraska. All rights reserved.the morning prior to feeding. These same three animals were used for both blood col-lections. The first blood collection was on d 28 of the finishing period after all cattle had been fully adapted onto their respective finishing diet. The second blood collection was on d 92 of the finishing period.Cattle were implanted with a TE- IS (Elanco Animal Health) on d 28 and reimplanted with a TE- S (Elanco Animal Health) on d 90 of the finishing period. The Heavy block was on feed for 153 days and the light and mid blocks were on feed for 167 days. Cattle were slaughtered at a commercial abattoir (Cargill Meat Solu-tions, Fort Morgan, CO) and carcass data collected.Data were analyzed using the mixed procedure of SAS for performance, car-cass and blood variables with block and treatment as fixed effects. Blood data were analyzed as a repeated measure over time. Due to missing carcass data on the heavy block, data from that block were omitted from the carcass and carcass adjusted analysis of performance leaving 36 pens with 4 replications per treatment for these observations.ResultsPerformance data are presented in Table 2. There were no significant interactions between distillers and urea inclusion (P ≥ 0.11) with the exception of F:G so only the main effects are presented. There was a significant quadratic interaction (P = 0.05) between distillers and urea inclu-sion for carcass adjusted F:G (Figure 1). At 10% distillers, F:G appears to remain consistent as urea is increased in the diet. When feeding 15% distillers added urea appears to have a quadratic effect on F:G with lower F:G at 0.5% urea inclusion. For 20% distillers in the diet adding urea at 0.5% of the diet appears to have a negative impact on F:G while1.0% urea resulted in similar performance to the 0 urea control. This interaction would suggest that when Effects of Urea and Distillers Inclusion in Finishing Diets  on Steer Performance and Carcass CharacteristicsBradley M. BoydJames C. MacDonaldMatthew K. LuebbeGalen E. EricksonSummary with ImplicationsAn experiment was conducted to evaluate the effect of supplemental urea in dry rolled corn based finishing diets containing low inclusions of distillers grains. Treatments were set up in a 3 × 3 factorial arrangement. The first factor was wet distillers inclusion at either 10, 15, or 20% of diet DM. The second factor was urea inclusion at either 0, 0.5, or 1.0% of diet dry matter. Increasing inclusion of distillers linearly improved feed conversion and linearly reduced dry matter intake. An interaction for feed efficiency was observed where there was no effect of added urea when 10% or 20% distillers was fed and a quadrat-ic effect was observed when 15% distillers grains was fed where 0.5% urea appeared to be optimum. Added urea in a finishing diet with 20 or 10% distillers has minimal impact on finishing performance; however, feeding 0.5% urea in a 15% distillers diet may be beneficial.IntroductionDistillers grains are a good source of protein containing around 30% CP with 63% of this CP being rumen ungradable protein. With inclusions of distillers grains in finishing diets being greater than 25% over the past 10 years, protein has been over fed; therefore, meeting protein re-quirements (RDP and MP) hasn’t been an issue. Previous research would suggest that when feeding distillers grains in dry rolled corn (DRC) based diets at greater than 25% of diet DM, no additional urea supple-mentation is needed to maintain animal performance. However, with increasing distillers grain price, inclusion of distillers has decreased to a level where adding sup-plemental urea may be beneficial. A recent survey suggested that, in the Midwest, the average inclusion of distillers in commer-cial feedlots is 19.9% of diet DM. Previous research has evaluated feeding 10 or 20% dry distillers with or without urea and they observed no performance response with added urea. However, there was a numer-ical improvement in feed conversion in the 10% distillers diet (2005 Nebraska Beef Cattle Report, pp 42– 44).With limited research on the topic, the objective of this research was to determine the effects of supplementing urea in dry rolled corn based finishing diets containing low inclusions of distillers grains.ProcedureFour hundred and thirty two cross-breed steers were utilized in a study at the Panhandle Research and Extension Center near Scottsbluff NE. Treatments were set up in a 3×3 factorial arrangement with factors consisting of three distillers inclusions (10, 15, or 20% of the diet DM) and three urea inclusions (0, 0.5, or 1.0% of diet DM). Diets were dry- rolled corn (DRC) based using corn silage as the roughage source (Table 1). A liquid supplement was utilized and contained either 0 or 1% urea and the 0.5% urea treatment was accomplished by mixing a 50:50 blend of the 2 supplements. Cattle were fed once daily in the morning and managed on a slick bunk protocol. Rumensin (Elanco Animal Health) was supplied to the cattle at 360 mg/hd/d and Tylan (Elanco Animal Health) was supplied at 90 mg/hd/d added to the diet using a mi-cro machine (Animal Health International). Three blocks were used with one replication in the light block, three replications in the middle block, and two replications in the heavy block. This design totaled 54 pens with 6 replications per treatment.Blood was collected twice during the finishing period for plasma urea nitrogen (PUN) analysis. Blood was collected from three randomly selected animals per pen in 98 · 2019 Nebraska Beef Cattle Reportmg/100 mL to be necessary for optimum performance to be maintained. The values for the current trial are more than double (> 17.8) this value suggesting that there was more than enough excess nitrogen in the blood to maintain performance across all treatments.ConclusionBased on these results, when feeding 10 or 20% distillers grains in a finishing diet added urea is of limited benefit for animal performance. However, when feeding 15% distillers grains in the diet adding 0.5% urea to the diet appears to improve feed efficien-cy. However, it is difficult to explain the variation across 10, 15, and 20% inclusion. Our conclusion is that urea supplementa-tion was unnecessary. Increasing inclusion of distillers grains in the diet even from 10 to 20% improved gain and reduced intake, thereby improving feed conversion.Bradley M. Boyd, graduate studentJames MacDonald, professor, University of Nebraska– Lincoln, Lincoln NEMatthew Luebbe, associate professor, University of Nebraska– Lincoln, Scottsbluff NEGalen E. Erickson, professor, University of Nebraska– Lincoln Department of Animal Science, Lincoln NEnot significant (P = 0.26) F:G appears to be quadratic with a plateau appearing at 0.5% urea. There was no difference (P = 0.49) in DMI observed for increasing urea levels. Average daily gain and final live weight increased linearly (P < 0.03) as distillers grains increased in the diet; however, ADG and final live weight tended to have a qua-dratic response (P < 0.09) with increasing levels of urea in the diet with maximum values at 0.5% inclusion.For carcass adjusted performance, a tendency for a linear increase (P ≤ 0.08) in final BW and ADG was observed for increasing levels of distillers grains. Both DMI and F:G linearly decreased (P < 0.01) as distillers grains was increased in the diet. Additionally F:G was linearly decreased (P = 0.02) with the addition of urea in the diet however, no other measures were signifi-cantly (P ≥ 0.14) affected by urea inclusion.A tendency for a linear increase (P = 0.08) in HCW was observed with increas-ing levels of distillers grains in the diet. Additionally, a linear increase (P < 0.01) in 12th rib fat thickness was observed with increasing levels of distillers grains in the diet. However, there were no other significant (P ≥ 0.15) differences for carcass characteristic for either distillers or urea inclusion in the diet. Plasma urea nitrogen linearly increased (P < 0.01) for both added distillers and added urea in the diet. Others have found a minimum BUN value of 7 feeding 10 or 20% distillers grains added urea in the diet has minimal benefit on per-formance but when feeding 15% distillers grains some added urea may be beneficial. However, with this type of interaction it is difficult to make conclusions and determine if the interaction is real or due to random variation in the data. Additionally, the missing carcass data from the heavy block of cattle may have had an effect on the data. A depression in animal performance for 20% distillers and 0.5% urea inclusion is the primary cause for the interaction, which is difficult to explain biologically.The remaining performance variables were analyzed for main effects. For live per-formance, DMI and F:G decreased linearly (P < 0.01) with increasing inclusion of dis-tillers grains. Additionally, a linear decrease (P = 0.05) in F:G was observed for increas-ing levels of urea in the diet. Visually, while Table 1. Diet ingredient composition as % of diet DM by treatmentIngredient10% Distillers 15% Distillers 20% Distillers0 0.5 1.0 0 0.5 1.0 0 0.5 1.0DRC, % DM 69 69 69 64 64 64 59 59 59WDGS, % DM 10 10 10 15 15 15 20 20 20Corn Silage, % DM 15 15 15 15 15 15 15 15 15Supplement1 , % DM 6 5.5 5 6 5.5 5 6 5.5 5Urea, % DM 0 0.5 1.0 0 0.5 1.0 0 0.5 1.0Crude Protein, % 10.8 12.2 13.6 12.0 13.4 14.7 13.1 14.5 15.9Initial MP Balance2, g/d - 105 - 47 8 - 41 14 28 - 6 94 39Initial RDP Balance, g/d - 196 - 54 86 - 158 - 19 118 - 118 16 147Midpoint MP Balance2, g/d - 51 15 70 17 86 95 67 168 115Midpoint RDP Balance, g/d - 210 - 58 94 - 170 - 21 126 - 127 17 1581 Micro machine was used to add 360 mg of Rumensin and 90 mg per steer of Tylan to the diet daily.2 Metabolizable Protein balance calculated using 1996 NRC Model to predict MP supply corrected for RDP balance deficiency if one existed (MP balance- (RDP balance*.64)). Initial MP balance is calculated for the end of the step up period and midpoint MP balance was calculated for the middle of the finishing period.Figure 1. Carcass adjusted F:G interaction distillers level and urea inclusion.2019 Nebraska Beef Cattle Report · 99 Table 2. Main effects of distillers inclusion and urea inclusion on performanceMeasureDistillers, % diet DMSEMP- Value Urea, % Diet DMSEMP- Value10 15 20 Lin Quad 0% 0.5% 1.0% Lin QuadLive PerformanceInitial BW, lb 617 616 615 1 0.06 0.94 617 616 616 1 0.22 0.75Final BW, lb 1328 1337 1345 6 0.03 0.94 1328 1344 1338 6 0.19 0.09ADG, lb/d 4.39 4.45 4.50 0.03 0.01 0.96 4.39 4.49 4.46 0.03 0.16 0.08DMI, lb/d 24.1 24.0 23.4 0.2 <0.01 0.16 23.9 23.9 23.7 0.2 0.49 0.61F:G 5.49 5.40 5.18 0.002 <0.01 0.25 5.43 5.32 5.32 0.002 0.05 0.26Carcass Adjusted PerformanceInitial BW, lb 583 582 581 1 0.09 0.99 582 583 581 1 0.43 0.25Final BW, lb 1277 1293 1298 8 0.08 0.63 1277 1298 1293 8 0.15 0.18ADG, lb/d 4.16 4.25 4.29 0.05 0.06 0.65 4.16 4.28 4.26 0.05 0.14 0.24DMI, lb/d 23.5 23.2 22.6 0.2 <0.01 0.55 23.2 23.3 23.0 0.2 0.45 0.46F:G 5.65 5.46 5.26 0.002 <0.01 0.93 5.56 5.43 5.38 0.002 0.02 0.50Carcass CharacteristicsHCW, lb 805 815 818 5 0.08 0.62 805 818 815 5 0.15 0.18Dressing % 62.1 62.5 62.4 0.2 0.19 0.19 62.3 62.2 62.4 0.2 0.81 0.59LM Area, in2 13.7 14.0 13.8 0.2 0.43 0.24 13.8 13.8 13.9 0.2 0.74 0.6312th Rib Fat, in 0.50 0.52 0.56 0.02 <0.01 0.84 0.53 0.52 0.52 0.02 0.75 0.89Marbling 447 456 440 7 0.45 0.12 447 448 449 7 0.82 0.97USDA Yield Grade 2.9 2.9 3.1 0.1 0.14 0.39 3.0 3.0 3.0 0.1 0.99 0.52PUN mg/100mL1 18.57 20.03 22.72 0.53 <0.01 0.33 17.81 20.31 23.20 0.50 <0.01 0.731 PUN = Plasma Urea Nitrogen

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Effects of Urea and Distillers Inclusion in Finishing Diets on Steer Performance and Carcass Characteristics

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