What s the Latest on Carbohydrates, Starch Digestibility, Shredlage and Snaplage for Dairy Cows?

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1 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 through Aug (USDA ERS, 2012) 1

2 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 % 5% SH UW II % 5% WM, WCS UW III % 10% SH UW IV % 6% SH OARDC % vs. 26% 5% CS 2

3 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

4 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 $/cow/day IOFC $/cow/day Revised using August-2012 milk component & feed prices 4

5 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

6 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

7 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 Milk, lb/d Milk/DMI <0.01 7

8 Impact of Rumensin on milk composition & component yields 0g/ton 18g/ton P-value Fat, % lb/d Protein, % lb/d MUN, mg/dl Milk Fat % Starch Rumensin (P = 0.15) 8

9 Impact of Rumensin on component corrected milk production efficiencies 0 g/ton 18 g/ton P-value FCM/DMI ECM/DMI SCM/DMI Lactation efficiency (Milk/DMI) 1.65 lb milk/lb DMI RSC NSC RSR NSR Treatment Starch Rumensin (P < 0.08) 9

10 Corn Shredlage Corn Shredlage Shredlage KP 30 mm TLOC 2.5 mm roll gap 19 mm TLOC 2.5 mm roll gap 10

11 Penn State Separator Box (as-fed basis) Samples obtained during feed-out from the silo bags Screen, mm Shredlage KP % 5.6% % 75.6% % 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% ± % ±

12 Experimental Diets (DM basis) Shredlage KP Shredlage 50% --- KP Silage % 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 % 3.5% % 52.9% % 35.8% Pan 7.3% 7.8% 12

13 3.5% FCM Yield by Week * * ** * P < 0.10 ** P < 0.01 Week Treatment Interaction (P < 0.03) Total Tract Starch Digestibility Treatment P < Week P <

14 HMC Silo Fermentation Increases Starch Digestibility 14

15 Prior to Ensiling Ensiled 240 d Hoffman et al., 2011, JDS Hoffman et al., 2011, JDS 15

16 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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18 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

19 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 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

20 a a a ab b b Week Treatment interaction (P < 0.05) 20

21 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

22 Corn Silage Ammonia-N Lab Years n Average Normal Range -----% of N Dairy One , Dairyland* , CVAS* , *Almost none of variation in ammonia content explained by DM content in either corn silage dataset Corn Silage Processing Score, 1131 Samples, CVAS % Inadequately Processed 51% Adequately Processed # of samples % Optimally Processed

23 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 23