1. 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.

2. Adapted from Joe Lauer, UW Madison Agronomy Dept.

3. 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

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

5. 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

6. 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

7. 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

8. 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

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

10. 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

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

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

13. Corn Silage Fermentation Increases Starch Digestibility!

14. Ensiling time effect
(P = 0.001)

15. Height of Cutting

16. 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

17. 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

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

19. Recommendation #2 is to harvest corn silage at a lower dry matter content. Less than 40% is the goal.
Image Source:

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

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

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

24. Questions?

25. Dairy Cattle Nutrition Website
Visit UW Extension
Dairy Cattle Nutrition Website