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Randy ShaverDairy Science Department, UW Madison
What’s the Latest on Carbohydrates, Starch Digestibility, Shredlage™ andSnaplage for Dairy Cows?
Average #2 yellow corn cash price in Minneapolis, MN at 5 year intervals from Sept. 1975 through Aug. 2012 (USDA ERS, 2012)
25% - ≥ 30% Starch Diets Common ?
USA Corn Price & Starch Content of Lactating Dairy Cow Diets
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Ingredient Starch%
Shelled corn 70Corn:SBM (65:35) 46
Corn Silage 30Soy hulls 5
Corn gluten feed 23Distillers grains 3
Whole cottonseed 1
DIM at Trial
Start-Up
Weeks on Trial
DietaryForage NDF
DietStarch
NS - RS
Partial Corn
Replacers
UW I 51 14 21% 5% SH
UW II 68 12 20% 5% WM, WCS
UW III 114 14 21% 10% SHUW IV 100 16 21% 6% SH
OARDC 74 16 23% vs. 26% 5% CS
Recent Continuous-Lactation Trials With Reduced-Starch Diets
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DMI for normal- & reduced-starch diets
DGSC partially replaced by High-Fiber Byproducts in UW I-IV & Corn Silage in OARDC to formulate RS diets
SCM yield for normal- & reduced-starch diets
DGSC partially replaced by High-Fiber Byproducts in UW I-IV & Corn Silage in OARDC to formulate RS diets
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SCM/DMI for normal- & reduced-starch diets
DGSC partially replaced by High-Fiber Byproducts in UW I-IV & Corn Silage in OARDC to formulate RS diets
UW I2010
UW II2011
UW III2011
UW IV2011
OARDC2011
Item (RS/NS)
Feed Cost
$/lb. DM
$/cow/day0.99
1.08
0.92
0.98
0.99
1.03
0.99
0.99
0.95
0.92
IOFC
$/cow/day1.00 0.93 0.96 0.96 0.93
Revised using August-2012 milk component & feed prices
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• NDF – Greater proportion of acetate
• Starch – Greater proportion of propionate
• Sugar– Greater proportion of butyrate or valerate
• Pectin/Soluble Fiber– Greater proportion of acetate
• Propionate impacts DMI, milk yield & composition, & lactation efficiency
Endproducts of Ruminal CHO Fermentation
• Broderick & Radloff (2004) Dried or Liquid Molasses vs. HMSC
• Broderick et al. (2008) Sucrose vs. Corn Starch
• Quadratic DMI & milk production responses• 5% - 7% Total Sugar (DM basis) TMR optimum 23% - 25% Starch (DM basis) in these trials
What About Sugars?
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Multiple Ration Groups
Important for effectively implementing reduced-starch diets Potential for fill limitation of DMI and thus milk production when corn starch partially replaced by forage NDF in high-group diets
Reduced lactation efficiency when corn starch partially replaced by byproduct NDF in high-group diets
Effects of Rumensin® in lactating cow diets with differing starch contents
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• UW-Madison Arlington free-stall barn• 16 pens of 8 cows each (90 ± 33 DIM)• Treatments NSR = 27% starch with 18 g Rumensin/ton TMR DM NSC = 27% starch without Rumensin RSR = 20% starch with 18 g Rumensin/ton TMR DM RSC = 20% starch without Rumensin
• Completely randomized design with 4-wk covariate on NSR followed by 12-wk of treatment Pen served as experimental unit for stats analysis
Study Methods
0 g/ton 18 g/ton P-value
DMI, lb/d 59.9 59.1 0.33
Milk, lb/d 90.6 93.5 0.01
Milk/DMI 1.52 1.58 <0.01
Impact of Rumensin on DMI, milk yield & Milk/DMI
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0 g/ton 18 g/ton P-value
Fat, %lb/d
3.873.51
3.823.55
0.520.56
Protein, %lb/d
3.222.91
3.172.95
0.020.37
MUN, mg/dL 12.2 12.6 0.06
Impact of Rumensin on milk composition & component yields
Milk Fat %
Starch × Rumensin (P = 0.15)
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0 g/ton 18 g/ton P-value
FCM/DMI 1.61 1.66 0.04
ECM/DMI 1.59 1.64 0.03
SCM/DMI 1.49 1.53 0.05
Impact of Rumensin on component corrected milk production efficiencies
Lactation efficiency (Milk/DMI)
1.4
1.45
1.5
1.55
1.6
1.65
RSC NSC RSR NSR
Treatment
lb m
ilk/lb
DM
I
Starch × Rumensin (P < 0.08)
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Corn
Shr
edlage
™
Corn
Shr
edlage
™Shredlage
KP
30 mm TLOC2.5 mm roll gap
19 mm TLOC2.5 mm roll gap
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Penn State Separator Box (as-fed basis)
Screen, mm Shredlage KP
19 31.5% 5.6%
8 41.5% 75.6%
1.18 26.2% 18.4%
Pan 0.8% 0.4%
Samples obtained during feed-out from the silo bags
Kernel Processing Score
Shredlage KP
% Starch Passing 4.75 mm Sieve 75.0% ± 3.3 60.3% ± 3.9
Samples obtained during feed-out from the silo bags
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Experimental Diets (DM basis)
Shredlage KPShredlage 50% ---
KP Silage --- 50%
Alfalfa Silage 10% 10%
Ground Dry Shelled Corn 10.3% 10.3%
Corn Gluten Feed 7.4% 7.4%
SBM 48%, solvent 6.9% 6.9%
SBM, expeller 9.3% 9.3%
Rumen-Inert Fat 1.9% 1.9%
Min/Vits 4.2% 4.2%
Penn State Separator Box (as-fed basis)
Screen, mm Shredlage KP19 15.6% 3.5%
8 38.2% 52.9%
1.18 38.9% 35.8%
Pan 7.3% 7.8%
TMR Samples
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3.5% FCM Yield by Week
*
***
* P < 0.10
** P < 0.01
Week × Treatment Interaction (P < 0.03)
Total Tract Starch Digestibility
TreatmentP < 0.001
WeekP < 0.03
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HMC Silo Fermentation Increases Starch Digestibility
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Prior to Ensiling Ensiled 240 d
Hoffman et al., 2011, JDS
Hoffman et al., 2011, JDS
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FeedGrainV2.0 IntegratesPrimary Factors Influencing Starch Digestibility
in High Moisture Corn
ProcessingParticle size
Harvest/StorageDry vs. HMC
DM of HMC/MaturitySilo Fermentation Time
MPSAmmonia
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18
Snaplage HMCAmmonia = 6.0% of CPKernel MPS = 1456 µ
Ammonia = 1.8% of CPMPS = 1335 µ
Feeding trial conducted during months 8 -10 in storage
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Snaplage HMCkd = 26%/hrRSD = 69%TTSD = 97%
kd = 19%/hrRSD = 62%TTSD = 95%
Kd, RSD & TTSD estimated from Ammonia & MPS with FeedGrainv2.0 - Hoffman et al. 2012
HMSC SnaplageSnaplage + Dry Corn
P <
Fat % 3.67%a 3.40%b 3.52%ab 0.05
Protein % 2.97% 2.93% 2.94% 0.89
MUN, mg/dL 11.4b 14.0a 10.3c <0.001
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a
b
a a
ab
b
Week × Treatment interaction (P < 0.05)
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Corn Silage Fermentation Increases Starch Digestibility
Corn Silage Fermentation & Starch Digestibility
Ruminal in situ starch & CP degradabilities for WPCS with longer ensiling (Newbold et al., 2006)
Ruminal in vitro starch digestibility for WPCS with longer ensiling (Hallada et al., 2008 & Der Bedrosian et al., 2010)
WPCS ammonia-N & ruminal in vitro starch digestibility with protease addition & longer ensiling (Young et al., 2011)
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Corn Silage Ammonia-N
Lab Years n Average Normal Range- - - - - % of N - - - - -
Dairy One 2000-2011 12,000 7.1 3.0 – 11.1
Dairyland* 2008 - 2011 1,900 5.7 2.7 – 10.7
CVAS* 2007-2012 44,000 9.6 7.8 – 11.4
*Almost none of variation in ammonia content explained by DM content in either corn silage dataset
0
50
100
150
200
250
# of samples
51% Adequately Processed42% Inadequately Processed
7% Optimally Processed
Corn Silage Processing Score, 1131 Samples, CVAS 2010 - 2011
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Corn Silage Fermentation & Starch Digestibility
Can ammonia-N & some measure of particle size, i.e. KPS or % starch passing 4.75 mm screen (Ferriera & Mertens, 2005), be used to predict corn silage digestibility during feed-out?
http://www.uwex.edu/ces/dairynutrition/
Visit UW Extension Dairy Cattle Nutrition Website