What s the Latest on Carbohydrates, Starch Digestibility, Shredlage and Snaplage for Dairy Cows? Randy Shaver Dairy Science Department, UW Madison USA Corn Price & Starch Content of Lactating Dairy Cow Diets 25% - 30% Starch Diets Common? Average #2 yellow corn cash price in Minneapolis, MN at 5 year intervals from Sept. 1975 through Aug. 2012 (USDA ERS, 2012) 1
Ingredient Starch% Shelled corn 70 Corn:SBM (65:35) 46 Corn Silage 30 Soy hulls 5 Corn gluten feed 23 Distillers grains 3 Whole cottonseed 1 Recent Continuous-Lactation Trials With Reduced-Starch Diets DIM at Trial Start-Up Weeks on Trial Dietary Forage NDF Diet Starch 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% SH UW IV 100 16 21% 6% SH OARDC 74 16 23% vs. 26% 5% CS 2
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 3
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 I 2010 UW II 2011 UW III 2011 UW IV 2011 OARDC 2011 Item (RS/NS) Feed Cost $/lb. DM 0.99 0.92 0.99 0.99 0.95 $/cow/day 1.08 0.98 1.03 0.99 0.92 IOFC $/cow/day 1.00 0.93 0.96 0.96 0.93 Revised using August-2012 milk component & feed prices 4
Endproducts of Ruminal CHO Fermentation 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 What About Sugars? 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 5
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 6
Study Methods 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 Impact of Rumensin on DMI, milk yield & Milk/DMI 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 7
Impact of Rumensin on milk composition & component yields 0g/ton 18g/ton P-value Fat, % lb/d 3.87 3.51 3.82 3.55 0.52 0.56 Protein, % lb/d 3.22 2.91 3.17 2.95 0.02 0.37 MUN, mg/dl 12.2 12.6 0.06 Milk Fat % Starch Rumensin (P = 0.15) 8
Impact of Rumensin on component corrected milk production efficiencies 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 Lactation efficiency (Milk/DMI) 1.65 lb milk/lb DMI 1.6 1.55 1.5 1.45 1.4 RSC NSC RSR NSR Treatment Starch Rumensin (P < 0.08) 9
Corn Shredlage Corn Shredlage Shredlage KP 30 mm TLOC 2.5 mm roll gap 19 mm TLOC 2.5 mm roll gap 10
Penn State Separator Box (as-fed basis) Samples obtained during feed-out from the silo bags 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% Kernel Processing Score Samples obtained during feed-out from the silo bags Shredlage KP % Starch Passing 4.75 mm Sieve 75.0% ± 3.3 60.3% ± 3.9 11
Experimental Diets (DM basis) Shredlage KP Shredlage 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) TMR Samples Screen, mm Shredlage KP 19 15.6% 3.5% 8 38.2% 52.9% 1.18 38.9% 35.8% Pan 7.3% 7.8% 12
3.5% FCM Yield by Week * * ** * P < 0.10 ** P < 0.01 Week Treatment Interaction (P < 0.03) Total Tract Starch Digestibility Treatment P < 0.001 Week P < 0.03 13
HMC Silo Fermentation Increases Starch Digestibility 14
Prior to Ensiling Ensiled 240 d Hoffman et al., 2011, JDS Hoffman et al., 2011, JDS 15
FeedGrainV2.0 Integrates Primary Factors Influencing Starch Digestibility in High Moisture Corn Processing Particle size MPS Harvest/Storage Dry vs. HMC DM of HMC/Maturity Silo Fermentation Time Ammonia 16
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Feeding trial conducted during months 8-10 in storage Snaplage HMC Ammonia = 6.0% of CP Kernel MPS = 1456 µ Ammonia = 1.8% of CP MPS = 1335 µ 18
Snaplage kd = 26%/hr RSD = 69% TTSD = 97% HMC kd = 19%/hr RSD = 62% TTSD = 95% Kd, RSD & TTSD estimated from Ammonia & MPS with FeedGrainv2.0 - Hoffman et al. 2012 HMSC Snaplage Snaplage + Dry Corn Fat % 3.67% a 3.40% b 3.52% ab 0.05 Protein % 2.97% 2.93% 2.94% 0.89 MUN, mg/dl 11.4 b 14.0 a 10.3 c <0.001 P < 19
a a a ab b b Week Treatment interaction (P < 0.05) 20
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) 21
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 Corn Silage Processing Score, 1131 Samples, CVAS 2010-2011 250 200 42% Inadequately Processed 51% Adequately Processed # of samples 150 100 7% Optimally Processed 50 0 22
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? Visit UW Extension Dairy Cattle Nutrition Website http://www.uwex.edu/ces/dairynutrition/ 23