Practical forage-ndf range in high-group TMR. Nutritional Constraints. Variable ruminal & total tract digestibility of starch

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1 Practical forage-ndf range in high-group TMR Luiz Ferraretto and Randy Shaver Dairy Science Department, UW Madison 24% forage-ndf High Quality Forages Large Forage Supply Forages Favorably Priced i.e. 60% 40% NDF 16% forage-ndf Limited Forage Supply Forages Expensive Moderate/Low Quality Forages i.e. 35% 46% NDF Nutritional Constraints 24% forage-ndf 16% forage-ndf NDF, ivndfd Fill Limitation of DMI Reduced Milk Yield pendf Milk Fat Depression Cow Health Varying proportions of Starch Sugar Pectin/Soluble Fiber Organic Acids Variable ruminal & total tract digestibility of starch NDF Greater proportion of acetate Starch Greater proportion of propionate Sugar Greater proportion of butyrate or valerate Pectin/Soluble Fiber Greater proportion of acetate These VFA s impact DMI, milk yield & composition, & feed conversions 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 Aug through Sept June 2012 (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 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 UW I 2010 UW II UW III UW IV OARDC Item Feed Cost $/lb. DM $/cow/day IOFC $/cow/day (RS/NS) NDF Greater proportion of acetate Starch Greater proportion of propionate Revised using Sept milk component & feed prices Propionate impacts DMI, milk yield & composition, & feed conversions Starch Digestion in Ruminants 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) Optimum in TMR With 23% - 25% Starch (DM basis) in these trials Rumen Small Intestine Digestion (Enzymatic) Glucose Microbial Fermentation VFA Propionate Glucose via liver Microbial Protein Hind Gut Microbial Fermentation VFA 3

4 Primary Factors Influencing Starch Digestibility in Corn Grain Corn grain harvest/processing effects Ruminal Digestibility (%) Total Tract Digestibility (%) Item n Starch n Starch Processing i.e. Particle size; Steam Treatment Harvest/Storage i.e. Dry vs. HMC DM of HM/Maturity; Fermentation Time Endosperm Type i.e. Prolamin; Prolamin-starch matrix; Hardness HMC a SFC a DRY b SEM P-value Corn grain harvest/processing effects Item DMI (kg) Milk (liters) Fat (%) FCM (liters) FCM/DMI HMC 22.4 b b 32.1 b 1.43 a Corn Grain MPS - DRY a SFC 23.4 ab ab 32.7 ab 1.38 DRY 23.6 a a 33.4 a 1.40 SEM P-value Geometric Mean Particle Size (µm) Corn Grain MPS - HMC a Corn endosperm type & starch digestibility Taylor and Allen, 2005 Lopes et al., 2009 Floury Vitreous Floury Opaque Isogenic Vitreous Ruminal, % 66.4 a 46.8 b 69.6 a 63.3 a 34.7 b Total Tract, % 96.9 a 92.1 b 95.1 a 96.6 a 89.6 b Adapted from Fredin,, Marshfield Lab Update 4

5 Ruminal Dig., % FeedGrainV2.0 Integrates Primary Factors Influencing Starch Digestibility in Dry Corn Processing Particle size MPS Endosperm Type Starch-Protein Matrix Hardness Vitreousness Prolamin Hoffman et al., 2012 June issue, JDS HMC Silo Fermentation Increases Starch Digestibility Increasing Length of Storage Increases Starch Digestion in HMC Benton et al., 2004 Univ. of Nebraska Ensiling Period (d) DRC 24 HMC 28RECON 30 HMC O * 35RECON Prior to Ensiling Ensiled 240 d Hoffman et al.,, JDS Hoffman et al.,, JDS 5

6 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 Hoffman et al., 2012 June issue, JDS Corn Silage Harvest Practices Influence Dairy Cattle Performance! Corn Silage Fermentation & Starch Digestibility Ruminal in situ starch degradability for HMC with > moisture content & longer ensiling (Benton et al., 2005) Ensiling HMC for 8 mos. zein protein subunits that crosslink starch granules (Hoffman et al., ) Suggests starch protein-matrix degraded by proteolytic activity Ammonia-N in HMC used to model effects of moisture content and duration of ensiling on total tract & ruminal starch digestibilities (Hoffman et al., 2012) 6

7 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., ) 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 Fermentation & Starch Digestibility Visit UW Extension Dairy Cattle Nutrition Website Can ammonia-n & some measure of particle size, i.e. CSPS or % starch passing 4.75 mm screen (Ferriera & Mertens, 2005), be used to predict corn silage digestibility during feed-out? 7