Matt Akins, Luiz Ferraretto, Shane Fredin & Randy Shaver Dairy Science Department, UW Madison

24% forage-NDF 16% forage-NDF High Quality Forages Large Forage Supply Forages Favorably Priced Limited Forage Supply Forages Expensive Moderate/Low Quality Forages Practical forage-NDF range in high-group TMR i.e. 60% 40% NDF i.e. 35% 46% NDF

24% forage-NDF 16% forage-NDF Fill Limitation of DMI Reduced Milk Yield peNDF Milk Fat Depression Cow Health Nutritional Constraints

24% forage-NDF 16% forage-NDF Dairy NRC Min. forage NDF & Max. NFC Dietary Guidelines 44% NFC 38% NFC High Fiber Byproducts Starchy Grains

Varying proportions of Starch Sugar Pectin/Soluble Fiber Organic Acids Analytical Errors CP, NDF, Fat, Ash 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 Impacts DMI, milk yield & composition, & feed conversions

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

Average #2 yellow corn cash price in Minneapolis, MN at 5 year intervals from Sept Aug through Sept July (USDA ERS, 2011) 25% - ≥ 30% Starch Diets Common ? Dietary Starch Content

IngredientStarch% Shelled corn70 Corn:SBM (65:35)46 Corn Silage30 Soy hulls5 Corn gluten feed23 Distillers grains3 Whole cottonseed1

DGSC partially replaced by High-Fiber Byproducts in UW I-III & Corn Silage in OARDC to formulate RS diets

DGSC partially replaced by High-Fiber Byproducts in UW I-III & Corn Silage in OARDC to formulate RS diets

DGSC partially replaced by High-Fiber Byproducts in UW I-III & Corn Silage in OARDC to formulate RS diets

Matt Akins & Randy Shaver Dairy Science Department, UW Madison Kelly Perfield & Howard Green Elanco Animal Health

Rumensin Increase milk-production efficiency (Milk/DMI) Reduce DMI These responses greater on reduced-starch diets

UW-Madison Arlington free-stall barn 16 pens of 8 cows (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 treatment period Pen served as experimental unit for stats analysis

Normal StarchReduced Starch % of DM Corn silage25 Alfalfa silage25 Dry ground corn Soyhulls SBM DDGS4.5 Mins-Vits-Adds3.9 Control or Rumensin Premix 0.9 Rumensin concentration 0 or 18 g/ton within NS & RS TMR

Normal StarchReduced Starch % of DM CP NDF Forage NDF19.5 Starch Ether Extract5.9 TDN 1x

NSRSP-value DMI, lb/d Milk, lb/d Milk/DMI

Starch × week (P < 0.01) * * * * †

0 g/ton18 g/tonP-value DMI, lb/d Milk, lb/d Milk/DMI <0.01

* * * Rumensin × week (P < 0.01)

NSRSP-value Fat, % lb/d Protein, % lb/d <0.01 MUN, mg/dL <0.01

* * * * Starch × week (P < 0.01)

0 g/ton18 g/tonP-value Fat, % lb/d Protein, % lb/d MUN, mg/dL

NSRSP-value SCM, lb/d SCM/DMI

0 g/ton18 g/tonP-value 3.5% FCM, lb/d ECM, lb/d SCM, lb/d

0 g/ton18 g/tonP-value FCM/DMI ECM/DMI SCM/DMI

Starch × Rumensin (P < 0.08)

0 g/ton18 g/tonP-value Body Weight, lb Condition Score Body Weight Change, lb/d

NSRSP-value Body Weight, lb Condition Score Body Weight Change, lb/d

NSRSP-value TT StarchD, % <0.01 NE L, Mcal/lb DM

0 g/ton18 g/tonP-value TT StarchD, % NE L, Mcal/lb DM

Reduced starch diet: Similar DMI and SCM yield Reduced milk and protein yields 18 g Rumensin/ton DM: Increased milk yield Reduced DMI as trial progressed Increased milk-production efficiency by 4% Similar milk fat and protein yields Few interactions between dietary starch content & Rumensin supplementation were detected Results support use of Rumensin in normal & reduced starch diets

The digestibility of starch from corn in dairy cows? Pat Hoffman & Randy Shaver Dairy Science Department University of Wisconsin - Madison

Primary Factors: Influencing Starch Digestibility in Feed Grains 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

FeedGrainV2.0 Integrates Primary Factors: Influencing Starch Digestibility in Feed Grains Processing Particle size Harvest/Storage Dry vs. HMC DM of HMC/Maturity Silo Fermentation Time Endosperm Type Starch-Protein Matrix Hardness Vitreousness MPS Ammonia Prolamin

FeedGrainV2.0

Snaplage HMC Ammonia = 6.0% of CP Kernel MPS = 1456 µ Ammonia = 1.8% of CP MPS = 1335 µ

Snaplage HMC kd = 26%/hr RSD = 69% TTSD = 97% kd = 19%/hr RSD = 62% TTSD = 95% Kd, RSD & TTSD estimated from Ammonia & MPS with FeedGrainv2.0 - Hoffman et al. 2012

HMSCSnaplage Snaplage + 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/dL11.4 b 14.0 a 10.3 c <0.001

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

Visit UW Extension Dairy Cattle Nutrition Website /