Corn Silage Evaluation: MILK2000 Challenges & Opportunities With MILK2006 Professor Randy Shaver Department of Dairy Science University of Wisconsin - Madison University of Wisconsin - Extension
Whole-Plant Corn Silage Grain ~40-45% of WPDM Avg. 28% starch in WPDM Variable grain:stover Stover= ~55-60% of WPDM Leaves = 15% of DM Stem = 20-25% of DM Cob+Shank+Husk= 20% of DM 80 to 98% starch digestibility Kernel maturity Kernel particle size Endosperm properties 40 to 70% NDFD lignin/ndf 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 poor Lignin to NDFD equation is theoretically based Lignin explains only about half of the in vitro NDFD variation Stover NDF & lignin contents & NDFD with maturity, while WP NDF & lignin contents are constant or as grain% increases
Relationship between lignified NDF and in vitro NDFD for corn & alfalfa forages In vitro NDF digestibility, %, 30h 70 60 50 40 30 20 Corn Silage R 2 = 0.54 Alfalfa R 2 = 0.56 0 5 10 15 20 25 Corn silage: 3-9% Alfalfa: 11-20 % Allen, 2003 Lignin, % of NDF
30-h NDFD (adapted from Allen, 2003) vs. NDF digestibility calculated using NRC-01 lignin equation Whole-Plant Lignin, % DM 2.1 3.1 4.2 Calculated NDFD 62 57 53 30-h NDFD 60 45 30
Measured NDFD or Estimated from Lignin? NDF, % Lignin, % Calc. NDFD 30-h NDFD 45.0 3.52 56 46.0 45.0 3.26 57 48.4 45.0 3.32 57 54.4 45.1 3.18 57 55.0 45.0 3.43 56 67.3 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 ruminal retention time 30-h was used in most cow trials Faster lab turn-around Better lab efficiency at 24-h?
The incubation time-point debate MILK2000 48-h MILK2006 48-h default, with 30-h or 24-h User Defined Option Lab average NDFD required NDFD DMIadjustment = (avg. NDFD NDFD) * 0.26 NDFD adjustment for summative TDN 1x equation
600 500 TMF113 Predicted F657 bm3 P33A14 TMF113 NDF Residue (g kg -1 ) 400 300 200 F657 bm3 Predicted P33A14 Predicted WQS C0 WQS C1 WQS C2 WQS C0 Predicted 100 WQS C1 Predicted WQS C2 Predicted 0 0 10 20 30 40 50 60 70 80 90 100 Time (hours) Adapted from Coors (data from Justen, 2004).
Variation in normal corn silage NDF digestibility calculated using NRC-01 lignin equation and table data Whole-Plant Lignin, % DM 1.0 (2stdev) 1.8 (1stdev) 2.6 (avg.) 3.4 (1 stdev) 4.2 (2stdev) Calculated NDFD 65 61 59 56 56
NDFD -- MILK2000 vs. MILK2006 MILK2000 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 NE L content but does impact NE L intake primarily thru its impact on DMI Calculation of NE L-3x from TDN 1x as per NRC (1989) MILK2006 A 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 NE L-3x adjusted for impact of NDFD on DMI (Oba and Allen, JDS, 1999) Calculation of NE L-3x from TDN 1x via DE and ME as per NRC (2001)
Mcal/lb. 0.82 0.8 0.78 0.76 0.74 0.72 0.7 0.68 0.66 0.64 Corn Silage NDFD% vs. NE L3x Calculated assuming corn silage with 35% DM proc., 27% starch, 45% NDF, and 58% avg. NDFD 0.66 MILK2006 0.69 0.73 0.69 0.75 0.81 46 50 54 58 62 66 70 46 50 54 58 62 66 70 NDFD% MILK2000
Corn Silage NDFD% vs. Milk per Ton Calculated assuming corn silage with 35% DM proc., 27% starch, 45% NDF, and 58% avg. NDFD 4100 4065 lb. M ilk/ ton Cs DM 3800 3500 3200 2900 MILK2000 MILK2006 3530 3579 3237 3074 2936 46 50 54 58 62 66 70 46 50 54 58 62 66 70 NDFD%
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 PAF Corn grain, ground dry 1.00 Corn grain, ground high moisture 1.04 Corn silage, normal 0.94 Corn silage, mature 0.87
Schwab-Shaver Energy Equation TDN 1-x = DIG CP + DIG FA + DIG Starch + DIG NSTNFC + DIG NDF 7
Predicted Starch Digestibility Starch digestibility (%) 95 90 85 Processed 80 75 Unprocessed 70 65 30 32 34 36 38 40 42 44 46 48 Whole plant DM (%) Adapted from Schwab et al., 2003.
Differences in calculation of tdnfc Based on corn silage with 41% NFC & 28% starch WP DM % NRC-01 tdnfc% Schwab et al., 2003 tdstarch&nstnfc% Unprocessed Processed 30 40 40 40 35 38 39 40 40 35 36 39 45 35 34 38
Corn Silage WP DM% vs. TDN 1x TDN % 71 70 69 68 67 66 65 64 63 MILK2006 Calculated assuming corn silage with 27% starch, 45% NDF, and 58% NDFD Unprocessed Processed 30 35 40 45 30 35 40 45 WP DM%
Corn Silage WP DM% vs. Milk per Ton lb. M ilk/ton CS DM 3300 3200 3100 3000 2900 2800 2700 Calculated assuming corn silage with 27% starch, 45% NDF, and 58% NDFD Unprocessed Processed 2600 30 35 40 45 30 35 40 45 MILK2006 WP DM%
Evaluating Starch Digestion in Ruminants In Vivo Total Tract Collections & Digesta Markers Cannulae (Rumen, Duodenum, Ileum) Macro In Situ. In Vitro. Rumen cannulae Incubation time? Starch-Feeds cannot be fine ground Post-Ruminal Enzymatic? Rumen fluid Incubation time? Starch-Feeds cannot be fine ground Post-Ruminal Enzymatic?
Corn Silage Processing Score Mertens, USDFRC & Dairyland Labs, Arcadia, WI Ro-Tap Shaker 9 sieves (0.6 thru 19 mm) and pan Analyze for starch on 4.75 mm & greater sieves % of starch passing 4.75 mm sieve CSPS >70% 70% to 50% < 50% Optimum Average Poor
Kernels and Large Fragments Were Retained on > 4.75-mm Sieves USDA-ARS US Dairy Forage Research Center
TDN % 69.5 69 68.5 68 67.5 67 Corn Silage KPS vs. TDN 1x Calculated assuming corn silage with 40% DM 27% starch, 45% NDF, and 58% NDFD 66.5 66 65.5 45 55 65 75 MILK2006 KPS %
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 vitreousness differences in corn samples Appears to offer better characterization of processed corn silage samples than KPS DSA can be related to total tract starch digestion More animal validation data needed Pilot study of assay across labs in progress
100 Degree of Starch Access, % of starch 80 60 40 20 Particle Size P<0.0001 0 Blazel et al., 2005 370 500 640 1100 3140 > 4000 Mean Particle Size, u m
100.0 Degree of Starch Access, % of starch 90.0 80.0 70.0 60.0 50.0 40.0 Dry Matter P<0.0001 r 2 = 0.76 62.0 67.0 72.0 77.0 82.0 87.0 92.0 Blazel et al., 2005 Corn Dry Matter, %
DSA vs. Total Tract Starch Digestibility from Literature Sources Total Tract Starch Dig. % 100 95 90 85 80 75 70 y = 0.198x + 76.9 R 2 = 0.73 Difference worth 3 lb. milk 65 0 10 20 30 40 50 60 70 80 90 100 Estimated DSA %
TDN % 72 71 70 69 68 67 66 65 64 63 MILK2006 Corn Silage DSA vs. TDN 1x Calculated assuming corn silage with 27% starch, 45% NDF, &58% NDFD 80 85 90 95 100 DSA %
MILK2006: Starch Digestion User Defined Options Default WP DM & Kernel Processing Regressions KPS DSA Ruminal in situ plus post-ruminal in vitro
TDN 1x Simulation -- Input Extremes TDN % 80 77 74 71 68 65 62 59 56 53 LQ 45% DM unproc., 20% starch, 54% NDF, and 46% NDFD HQ 30% DM proc., 34% starch, 36% NDF, and 70% NDFD 76.3 MILK2000 MILK2006 57.3 56.2 79.9
Milk per Ton Simulation -- Input Extremes 4400 LQ 45% DM unproc., 20% starch, 54% NDF, and 46% NDFD HQ 30% DM proc., 34% starch, 36% NDF, and 70% NDFD 4256 4000 lb. M ilk/ ton CS DM 3600 3200 2800 2400 MILK2006 2242 3617 MILK2000 2418 2000
Milk per Ton -- High NDF, NDFD vs. Low NDF, NDFD Ivan et al., JDS, 2005 lb. M ilk/ton CS DM 3800 3700 3600 3500 3400 3300 3200 3100 3000 LF 26% starch, 49% NDF, 58% NDFD HF 22% starch, 53% NDF, 67% NDFD MILK2000 MILK2006 LF HF LF HF
Milk per Ton -- High NDF, NDFD vs. Low NDF, NDFD Ivan et al., JDS, 2005 300 MILK2000 297 LF 26% starch, 49% NDF, 58% NDFD HF 22% starch, 53% NDF, 67% NDFD lb. M ilk/ton CS DM 250 200 150 MILK2006 132 Calculated from animal data 168 100 HF - LF HF - LF HF - LF
Treatment differences for model-predicted milk per ton versus milk per ton from in vivo data 300 250 200 150 100 50 0-50 -100-150 MILK2006 Calculated from 10 JDS papers with 13 comparisons MILK2000
Treatment differences for model-predicted milk per day versus milk per day in vivo data 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0-0.5-1.0-1.5-2.0 MILK2006 Calculated from 10 JDS papers with 13 comparisons MILK2000
UW Correlations n = 3727 treatment means r-values Milk per Ton DM 2006 Milk per Ton DM 2000 Milk per Ton DM 1995 Milk per Ton DM 1991 NDF -0.46-0.40-0.94-0.99 Starch 0.48 0.44 0.75 0.74 NDFD 0.49 0.70 0.16-0.10 StarchD 0.30 0.21-0.25-0.27
UW Correlations n = 3727 treatment means r-values Milk per Acre 2006 Milk per Acre 2000 Milk per Acre 1995 Milk per Acre 1991 DM Yield tons/acre 0.97 0.97 0.88 0.85 Milk per Ton DM 0.23 0.20 0.52 0.61
Relationship between milk per acre and milk per ton of corn hybrids in South Central WI during 2002. Milk per Acre (lb/a) 38000 36000 34000 32000 30000 28000 26000 High yield RK668 D2660 DKC6411 7625RRBt K8105LFRR LG2499 DST10419 CX1020Bt 8523IT 35R58 N59Q9 N48V8 6068Bt RX601RRYG T7095 P35D45 DKC6019RRYGCB 34B23 S6408Bt N51Z7 JC7 DKC5824 LGX52001 56K44 FS4042Bt RX664 GS1061 H8250 CX1080A 33B51 DKC6009 DKC5878YGCB RX730RRYG HC350 HiDF3600 DKC5334RRYGCB 24X G8779 LC4531 T7012 6406Y G7366 HiDF3300 H2387 8590IT S9617 DKC4446RRYGCB B3203 H6775Bt LC7415 JC8 DKC5073 DKC6017 LG2488 FS4481 T6900 JS5450 B3195 34M95 High yield and quality 24000 22000 3200 3300 3400 3500 3600 3700 Milk per Ton (lb/t) F377 F407 F657 High quality
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