1
2
3	VITREOUS VS FLOURY ENDOSPERM Bright yellow = germ Light yellow = vitreous endosperm White = floury endosperm
4	Why the interest in corn vitreousness? About ½ & ¾ of the energy in corn silage & corn grain, respectively, from starch as per summative equation Reduced starch digestibility at advanced maturity of corn silage & high moisture corn Variable starch digestibility response to kernel processing Starch digestibility differences in commercially available hybrids? Improved selection of future corn hybrids for starch digestibility to improve utilization of corn-based diets?
5
6	Kernel vitreousness vs. ruminal in situ starch availability for a dent vs. a flint type with advancing maturity
7	Kernel vitreousness, density, & ruminal starch availability of dent vs. flint hybrids
8	Endosperm type and kernel processing of corn silage Longuski et al. & Fanning et al., 2002 JDS abstracts Kernel processing effects in a vitreous vs. a floury hybrid at MI & NE sites Trend for greater DMI reduction due to processing for floury than vitreous silage Processing decreased milk fat 0.24 % units for vitreous but not for floury corn silage FCM/DMI 5% higher for floury than vitreous silage TT starch digestibility higher for floury silage diets
9	Hybrid, maturity, & processing effects in corn silage Johnson et al., JDS, 2002 Kernel processing effects in 2 hybrids at 3 maturities TT starch digestibility declined as kernel vitreousness increased in relationship to hybrid & maturity differences This decline was steeper in unprocessed than processed corn silage
10
11	Methods 14 US dent & 5 Brazilian flint corn hybrids US hybrids harvested at ½ ML, BL, 21d past BL Brazilian hybrids harvested at 21d past BL Kernel vitreousness by manual dissection Kernel density using a picnometer Ruminal in situ DM & starch availabilities (4 mm grind) - 3 mature US dent & 3 mature Brazilian flint hybrids - 2 US hybrids (high & low vitreousness) at 3 maturities
12	Kernel vitreousness & density of US & Brazilian commercial hybrids
13
14	Characteristics of 14 US dent corn hybrids harvested at 3 maturities
15
16
17
18
19	Kernel vitreousness of selected hybrids harvested in 2001 at black-layer maturity from plots in Wisconsin D. Majee, unpublished
20	Predicted ruminal starch availability of selected hybrids harvested in 2001 at black-layer maturity from plots in Wisconsin D. Majee, unpublished
21
22
23
24	Potential Benefits of Kernel Processing > Ruminal and total tract starch digestion > Response on dry silage & more vitreous hybrids? > Milk yield & fat % < Sorting of cobs Longer chop--More effective fiber
25	Production Responses to Kernel Processing 9 publications with 17 treatment comparisons summarized Average milk response of +1.8 lb/cow/day with a range of –2.6 to +4.4 lb/cow/day Positive response in 13 treatment comparisons with an average milk response of +2.4 lb/cow/day and a range of 0.2 to +4.4 lb/cow/day
26	Digestibility Responses to Kernel Processing Total tract
27	Predicted Total Tract Starch Digestibility Shaver, 2002
28	Impact of kernel processing on returns Up to $6,000 difference annually per 100 cows
29	Effect of kernel processing on diet sorting Ferreira, 2002; USDFRC & UW-Madison
30
31
32	Kernel Processing 1 to 3 mm recommended roll clearance - Varies with WP and kernel moisture > 95% Kernel breakage, and no cobs > 1/8th ring
33	Crop Processing Options Roller mill on self-propelled choppers - Custom operators - Large dairy/crop operations Roller mill on pull-type choppers Roller mill at blower - 24” to 48” wide mills (400 lb to ton per min.)
34	Economics of Crop Processing 1 to 2 lb. Milk Response/cow/day = $35-$70 per lactation Hire custom chop with CP unit = $10-$15 per lactation - Assumed $2.00-$3.00 per ton (as fed) Purchase Pull-Type chopper with CP unit = Annual cost of $20-$30 per lactation ($10,000-$15,000.00 X 19.1%)/100 cows Stationary roller at blower = Annual cost of $30-$40 per lactation ($15,000-$20,000.00 X 19.1%)/100 cows = Estimated rental cost of $15-$20 per lactation
35
36	Chop length Too fine - Lack of effective fiber - Low milk fat test - Rumen acidosis - Laminitis - High cull rate Too coarse - Poor packing - Potential mold problems - Silo face spoilage - Sorting in feed bunk - Poor herd performance - Kernel processor wear
37	Literature Summary of Corn Silage Particle Size vs. Chewing Activity 6 publications 28 treatment comparisons Lactating dairy cows 2 publications, 15 treatment comparisons fed CS diets 4 publications, 13 treatment comparisons fed mixed diets
38	Corn silage diets 528.9+(38.0%>9mm)-(.93%>9mmSQ); RSQ=.86; Int., x, & xSQ (P<0.05)
39	Mixed diets 363.8+(5.6%>9mm)-(0.07%>9mmSQ); RSQ=.40; Int., x, & xSQ (P<0.05)
40	Chop length effects in non-BMR processed corn silage Bal et al., 2000
41	Chop length effects in non-BMR processed corn silage Bal et al., 2000 3/8” vs. 9/16” vs. ¾” TLC - No difference in ruminal pH or VFA - No difference in chewing activity - ¾” TLC prevented depression in TT NDF digestion from processing - ¾” TLC improved ruminal mat consistency - Machine throughput greater & power requirements lower for ¾” TLC
42	Chop length effects in BMR corn silage Schwab et al., 2002
43	Chop length effects in BMR corn silage Schwab et al., 2002
44	Chop length effects in BMR corn silage Schwab et al., 2002
45	Corn silage vs. masticate particle size Schwab et al., 2002
46	Recommended chop length Harvester fitted with crop processor ¾ inch TLC - 15% to 25% on top screen of PSU- Nasco box - ½ inch TLC when WP DM > 40% - Available data shows no benefit to > ¾” TLC even with processed BMR corn silage
47	Visit UW-Madison Dairy Science Department Website http://www.wisc.edu/dysci/