Corn Silage Evaluation: MILK2000 Challenges &
Opportunities With MILK2006
Professor Randy Shaver
Department of Dairy ScienceUniversity of Wisconsin - MadisonUniversity of Wisconsin - Extension
80 to 98% starch digestibility•Kernel maturity •Kernel particle size•Endosperm properties
40 to 70% NDFD• lignin/NDF
Grain ~40-45% of WPDM Stover= ~55-60% of WPDMLeaves = 15% of DMStem = 20-25% of DMCob+Shank+Husk=
20% of DM
Whole-Plant Corn Silage
•Avg. 28% starch in WPDM•Variable grain:stover
Adapted from Joe Lauer, UW Agronomy
NRC (2001) Dairy TDN
TDN 1-X =tdCP + (tdFA x 2.25) + tdNDF + tdNFC -7
Why measure NDFD in vitro vs. calculating via lignin?
Lignin wet chem assay difficult & its calibration with NIRS has been poorLignin to NDFD equation is theoretically basedLignin explains only about half of the in vitroNDFD variation
Stover NDF & lignin contents & NDFD with maturity, while WP NDF & lignin contents are constant or as grain% increases
0 5 10 15 20 25
AlfalfaR2 = 0.56
CornSilageR2 = 0.54
In v
itro
ND
F di
gest
ibili
ty, %
, 30h 70
60
50
40
30
20
Lignin, % of NDF
Corn silage:3-9%
Alfalfa:11-20 %
Relationship between lignified NDF and in vitro NDFD for corn & alfalfa forages
Allen, 2003
30-h NDFD (adapted from Allen, 2003) vs. NDF digestibility calculated using NRC-01 lignin equation
535762
Calculated NDFD
304.2453.1602.1
30-h NDFDWhole-PlantLignin, % DM
Measured NDFD or Estimated from Lignin?
56
57
57
5756
Calc. NDFD46.03.5245.0
67.33.4345.0
55.03.1845.1
54.43.3245.0
48.43.2645.0
30-h NDFDLignin, %NDF, %
Corn silage data set from Van Amburgh (2004)Similar relationships from 36.5 to 51.8% NDF
Adapted from: Rick Grant, NRAES Silage Conf., 2006
The incubation time-point debate
48-hr.Reflects maintenance intake for use in NRC summative equation
Less influenced by lag & rate, so possibly lower COV
30- or 24-hr.30-h more closely related to ruminalretention time30-h was used in most cow trialsFaster lab turn-aroundBetter lab efficiency at 24-h?
The incubation time-point debate
MILK200048-h
MILK200648-h default, with 30-h or 24-h User Defined Option
Lab average NDFD requiredNDFD DMIadjustment = (avg. NDFD – NDFD) * 0.26
NDFD adjustment for summative TDN1x equation
0
100
200
300
400
500
600
0 10 20 30 40 50 60 70 80 90 100
Time (hours)
ND
F R
esid
ue (g
kg-1
)
F657 bm3
P33A14
TMF113
WQS C0
WQS C1
WQS C2
TMF113 Predicted
F657 bm3 Predicted
WQS C2 Predicted
P33A14 Predicted
WQS C0 Predicted
WQS C1 Predicted
Adapted from Coors (data from Justen, 2004).
Variation in “normal “ corn silage NDF digestibility calculated using NRC-01 lignin equation and table data
564.2 (2stdev)
563.4 (1 stdev)
592.6 (avg.)
611.8 (1stdev)
651.0 (2stdev)
Calculated NDFD
Whole-PlantLignin, % DM
NDFD -- MILK2000 vs. MILK2006MILK2000
A 1%-unit change in NDFD from lab average NDFD changes DMI 0.37 lb (Oba and Allen, 1999, JDS)Double counting of TDN & DMI changes related to changes in NDFD
Tine et al. (2001, JDS) and Oba and Allen (1999, JDS)At production levels of intake, NDFD has minimal impact on NELcontent but does impact NEL intake primarily thru its impact on DMI
Calculation of NEL-3x from TDN1x as per NRC (1989)
MILK2006A 1%-unit change in NDFD from lab average NDFD changes DMI 0.26 lb (Jung, 2004, MN Nutr. Conf.; Oba and Allen, 2005, Tri-State Nutr. Conf.)NDFD used for calculating NEL-3x adjusted for impact of NDFD on DMI (Oba and Allen, JDS, 1999) Calculation of NEL-3x from TDN1x via DE and ME as per NRC (2001)
0.75
0.69
0.81
0.69
0.66
0.73
0.640.660.68
0.70.720.740.760.78
0.80.82
46 50 54 58 62 66 70 46 50 54 58 62 66 70NDFD%
Mca
l/lb
.Corn Silage NDFD% vs. NEL3x
Calculated assuming corn silage with 35% DM proc., 27% starch, 45% NDF, and 58% avg. NDFD
MILK2006
MILK2000
3579
3237
4065
3074
2936
3530
2900
3200
3500
3800
4100
46 50 54 58 62 66 70 46 50 54 58 62 66 70
NDFD%
lb. M
ilk/t
on C
s D
MCorn Silage NDFD% vs. Milk per Ton
Calculated assuming corn silage with 35% DM proc., 27% starch, 45% NDF, and 58% avg. NDFD
MILK2006
MILK2000
NRC (2001) Dairy TDN
TDN 1-X =tdCP + (tdFA x 2.25) + tdNDF + tdNFC -7
NRC (2001) Dairy TDN
tdNFC = NFC% x 0.98 x PAF
PAFCorn grain, ground dry 1.00Corn grain, ground high moisture 1.04Corn silage, normal 0.94Corn silage, mature 0.87
Schwab-Shaver Energy Equation
TDN1-x =
DIGCP + DIGFA + DIGStarch + DIGNSTNFC + DIGNDF – 7
Predicted Starch Digestibility
65
70
75
80
85
90
95
30 32 34 36 38 40 42 44 46 48
Whole plant DM (%)
Sta
rch
dige
stib
ility
(%)
Unprocessed
Processed
Adapted from Schwab et al., 2003.
Differences in calculation of tdNFC
34363940
Unprocessed
Schwab et al., 2003tdStarch&NSTNFC%
38394040
Processed
35353840
NRC-01 tdNFC%
45403530
WPDM %
Based on corn silage with 41% NFC & 28% starch
636465666768697071
30 35 40 45 30 35 40 45WP DM%
TDN
%Corn Silage WP DM% vs. TDN1x
Calculated assuming corn silage with 27% starch, 45% NDF, and 58% NDFD
Unprocessed Processed
MILK2006
2600
2700
2800
2900
3000
3100
3200
3300
30 35 40 45 30 35 40 45WP DM%
lb. M
ilk/t
on C
S D
MCorn Silage WP DM% vs. Milk per Ton
Calculated assuming corn silage with 27% starch, 45% NDF, and 58% NDFD
Unprocessed Processed
MILK2006
Evaluating Starch Digestion in Ruminants…………
In Vivo…… Total Tract Collections & Digesta MarkersCannulae (Rumen, Duodenum, Ileum)
Macro In Situ…. Rumen cannulaeIncubation time?Starch-Feeds cannot be fine groundPost-Ruminal Enzymatic?
In Vitro…. Rumen fluidIncubation time ?Starch-Feeds cannot be fine groundPost-Ruminal Enzymatic?
Corn Silage Processing ScoreMertens, USDFRC & Dairyland Labs, Arcadia, WI
Ro-Tap Shaker9 sieves (0.6 thru 19 mm) and panAnalyze for starch on 4.75 mm & greater sieves
% of starch passing4.75 mm sieve CSPS>70%70% to 50%< 50%
OptimumAveragePoor
Kernels and Large Fragments Were Retained on > 4.75-mm Sieves
US Dairy Forage Research CenterUSDA-ARS
65.566
66.567
67.568
68.569
69.5
45 55 65 75
KPS %
TDN
%Corn Silage KPS vs. TDN1x
Calculated assuming corn silage with 40% DM 27% starch, 45% NDF, and 58% NDFD
MILK2006
Degree of Starch Access (DSA)Blasel, Hoffman and Shaver, JAFST, 2006
Adaptation of food industry assay “Degree of Starch Gelatinization”Detects particle size, moisture, and vitreousnessdifferences in corn samplesAppears to offer better characterization of processed corn silage samples than KPSDSA can be related to total tract starch digestion
More animal validation data needed
Pilot study of assay across labs in progress
0
20
40
60
80
100
370 500 640 1100 3140 > 4000Mean Particle Size, u m
Deg
ree
of S
tarc
h A
cces
s, %
of s
tarc
h
Particle Size P<0.0001
Blazel et al., 2005
r2 = 0.76
40.0
50.0
60.0
70.0
80.0
90.0
100.0
62.0 67.0 72.0 77.0 82.0 87.0 92.0Corn Dry Matter, %
Deg
ree
of S
tarc
h A
cces
s, %
of s
tarc
h
Dry Matter P<0.0001
Blazel et al., 2005
DSA vs. Total Tract Starch Digestibility from Literature Sources
y = 0.198x + 76.9R2 = 0.73
65
70
75
80
85
90
95
100
0 10 20 30 40 50 60 70 80 90 100
Estimated DSA %
Tota
l Tra
ct S
tarc
h Di
g. %
Difference worth 3 lb. milk
63646566676869707172
80 85 90 95 100
DSA %
TDN
%Corn Silage DSA vs. TDN1x
Calculated assuming corn silage with 27% starch, 45% NDF, &58% NDFD
MILK2006
MILK2006: Starch DigestionUser Defined Options
DefaultWP DM & Kernel Processing Regressions
KPS
DSA
Ruminal in situ plus post-ruminal in vitro
79.9
57.3
76.3
56.2
53
56
59
62
65
68
71
74
77
80
TDN
%TDN1x Simulation -- Input Extremes
LQ 45% DM unproc., 20% starch, 54% NDF, and 46% NDFD
HQ 30% DM proc., 34% starch, 36% NDF, and 70% NDFD
MILK2000MILK2006
4256
2418
3617
2242
2000
2400
2800
3200
3600
4000
4400
lb. M
ilk/t
on C
S D
MMilk per Ton Simulation -- Input Extremes
LQ 45% DM unproc., 20% starch, 54% NDF, and 46% NDFD
HQ 30% DM proc., 34% starch, 36% NDF, and 70% NDFD
MILK2000
MILK2006
3000
3100
3200
3300
3400
3500
3600
3700
3800
LF HF LF HF
lb. M
ilk/t
on C
S D
MMilk per Ton -- High NDF, NDFD vs. Low NDF, NDFD
Ivan et al., JDS, 2005
LF 26% starch, 49% NDF, 58% NDFD
HF 22% starch, 53% NDF, 67% NDFD
MILK2000
MILK2006
168
132
297
100
150
200
250
300
HF - LF HF - LF HF - LF
lb. M
ilk/t
on C
S D
MMilk per Ton -- High NDF, NDFD vs. Low NDF, NDFD
Ivan et al., JDS, 2005
LF 26% starch, 49% NDF, 58% NDFD
HF 22% starch, 53% NDF, 67% NDFD
MILK2000
MILK2006
Calculated fromanimal data
Treatment differences for model-predicted milk per ton versus milk per ton from in vivo data
-150
-100
-50
0
50
100
150
200
250
300
MILK2006
MILK2000
Calculated from 10 JDS papers with 13 comparisons
Treatment differences for model-predicted milk per day versus milk per day in vivo data
-2.0-1.5-1.0-0.50.00.51.01.52.02.53.03.5
MILK2006
MILK2000
Calculated from 10 JDS papers with 13 comparisons
UW Correlationsn = 3727 treatment means
0.740.750.440.48Starch
-0.100.160.700.49NDFD
-0.27-0.250.210.30StarchD
-0.99-0.94-0.40-0.46NDF
Milk per Ton DM1991
Milk per Ton DM1995
Milk per Ton DM2000
Milk per Ton DM2006
r-values
UW Correlationsn = 3727 treatment means
0.610.520.200.23Milk per Ton DM
0.850.880.970.97DM Yieldtons/acre
Milk per Acre1991
Milk per Acre1995
Milk per Acre2000
Milk per Acre2006
r-values
Milk per Ton (lb/T)3200 3300 3400 3500 3600 3700
Milk
per
Acr
e (lb
/A)
22000
24000
26000
28000
30000
32000
34000
36000
38000
RX601RRYG
RX664
RX730RRYG
B3195
B3203
S6408Bt
F657
CX1020Bt
CX1080AD2660
DST10419
HiDF3300
HiDF3600
DKC4446RRYGCB
DKC5073
DKC5334RRYGCB
DKC5824
DKC5878YGCBDKC6009
DKC6017
DKC6019RRYGCB
DKC6411
56K44
24X
8523IT
8590IT
G8779
GS1061
H2387
H6775Bt
H8250FS4042Bt
FS4481
7625RRBt HC350
JC7
JC8
JS5450
K8105LFRRLC4531
LC7415
6068Bt
LG2488
LG2499
LGX52001
G7366
F377
F407
N48V8
N51Z7
N59Q9
6406Y
33B51
34B23
34M95
P35D45
35R58
RK668 S9617
T6900
T7012
T7095
Highyield
High yieldand quality
Highquality
Relationship between milk per acre and milk per ton of corn hybrids in South Central WI during 2002.
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