Analysis of corn silage for dairy cows Randy Shaver, Ph.D., PAS, ACAN Dairy Science Department Mention of companies, labs, trade names, products or assays solely for the purpose of providing specific information or examples and does not imply recommendation, endorsement or exclusion.

Adapted from Joe Lauer, UW Madison Agronomy Dept.

Corn Silage Quality Indicators for High-Producing Dairy Herds Parameter Indicates Better Quality Primary Reason NDF Rumen Fill Limitation of DMI Potential for production response or feeding of higher-forage diets Lignin uNDF240 NDFD30 TTNDFD Starch Energy Density Potential for production response or feeding less corn grain Milk per ton Quality Index for Ranking

USA Corn Silage Quality Summary Parameter Indicates Better Quality n Normal Range NDF (% DM) 384,715 36 - 46 Lignin (% DM) 344,134 3 – 4 uNDF240 (% DM) 81,418 8 - 13 NDFD30 (% NDF) 170,634 48 - 60 TTNDFD (% NDF) 27,954 Starch (% DM) 347,759 25 - 39 Milk per ton 136,056 1344 - 1674 Summary of combined multi-year, multi-lab (CVAS, DairyOne, RRL, DLL) data, except TTNDFD only from RRL

Milk Per Ton MILK-2006 Model Energy content via summative energy equation (Schwab et al., 2003, JAFST) DMI via NDF% and ivNDFD DMI × Energy Content = Energy Intake Milk Yield predicted from energy intake

OARDC from NRC-2001 modified for corn silage by Schwab et al OARDC from NRC-2001 modified for corn silage by Schwab et al., 2003, JAFST

How is TTNDFD determined? Standardized iv NDFD (24, 30, 48h) and uNDF Forage sample Rumen and hindgut digestion Rate of fiber digestion (kd) Potentially digestible NDF (pdNDF) TTNDFD (total tract NDF Digestibility) PD NDF * kd/(kd +kp) Slide adapted from Dave Combs, UW Madison

TTNDFD combines in vitro rate of NDF digestion with uNDF to improve the prediction of in vivo fiber digestion Slide adapted from Dave Combs, UW Madison

Ruminant Starch Digestion Rumen Microbial Fermentation VFA Propionate Glucose via liver Microbial Protein Small Intestine Digestion (Enzymatic) Glucose Hind Gut Microbial Fermentation VFA

Kernel Processing Score Mertens, USDFRC Ro-Tap Shaker 9 sieves (0.6 thru 19 mm) and pan Analyze for starch on 4.75 mm & > sieves % of starch passing 4.75 mm sieve CSPS >70% 70% to 50% < 50% Excellent Adequate Poor

Corn Silage Processing Improves (RRL Data, 2013 to 2015) Crop Year Count (n) Average CSPS Normal Range Percent Excellent Percent Poor 2013 725 56 44 - 68 12% 33% 2014 2155 65 54 - 76 8% 2015 847 68 57 - 79 48% 6% Summarized from data provided by Dr. John Goeser, RRL

Conventional Processor Harvest Guidelines Conventional Processor TLOC: 13-19 mm 15%-25% PSU box top screen Roll Gap: 1-3 mm DM%: 34%-38%

Corn Silage Fermentation Increases Starch Digestibility!

Ensiling time effect (P = 0.001)

Height of Cutting

High vs. Normal Cut Corn Silage 11 trial average summarized by Wu & Roth; DAS 03-72 Item 15 cm Ht. 45 cm Ht. DM, % 38 40 NDF, % 42 39 IVNDFD, % of NDF 51 54 Starch, % 31 32 Tons DM per hectare 20 19

High vs. Normal Cut Corn Silage Neylon & Kung, JDS, 2003 Item Normal Cut High Cut DMI, kg/d 25.5 Milk, kg/d 45.0b 46.8a

Height of Cutting Higher Cutting? < NDF, ADF, & lignin > IVNDFD < whole-plant moisture DM yield loss of 5-8% < nitrate concerns < soil erosion

Recommendation #2 is to harvest corn silage at a lower dry matter content. Less than 40% is the goal. Image Source: http://meyerdairy.wordpress.com/2012/08/31/corn-silage-harvest-2012/

Rock River Lab – Chile Overall Corn Silage Summary Parameter n Mean Normal Range CP (% DM) 638 7 6 - 8 aNDF (% DM) 42 36 - 48 Lignin (% DM) 3.7 3 - 4 Starch (% DM) 31 25 - 37 NDFD30 636 54 49 - 59 TTNDFD 537 41 37 - 45 uNDF240 11 8 - 14

Rock River Lab – Chile Contest Corn Silage Summary Parameter n Mean Normal Range CP (% DM) 132 7 6 - 8 aNDF (% DM) 40 36 - 44 Lignin (% DM) 3.6 3 - 4 Starch (% DM) 33 29 - 37 NDFD30 53 48 - 58 TTNDFD 41 37 - 44 uNDF240 10 7 - 13

Rock River Lab – Chile Contest Corn Silage Summary Parameter n Mean Normal Range Milk (liters) Per Ton 132 1454 1339 - 1569

Questions?

Dairy Cattle Nutrition Website Visit UW Extension Dairy Cattle Nutrition Website http://www.shaverlab.dysci.wisc.edu/