Fiber Digestibility & Corn Silage Evaluation. Joe Lawrence Cornell University PRO-DAIRY

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1 Fiber Digestibility & Corn Silage Evaluation Joe Lawrence Cornell University PRO-DAIRY

2 Three key elements of forage quality Maturity (stage of harvest/grain fill) Neutral detergent fiber (NDF) content Lignin in conjunction with NDF Starch content in corn silages Fermentation/preservation quality Neutral Detergent Fiber digestibility (NDFd) Related to climate/growing conditions, maturity at harvest, and genetics Slide Credit: Dr. Tom Overton

3 Adjusting forage feeding levels based upon maturity Forage NDF as a % of intake Thumb rule 0.9 to 1.0% of BW for lactating dairy cows Example 1500 lb cow 1500 lbs x 1.0% of BW = 15 lbs of forage NDF If forages average 50% NDF 15 lbs of forage NDF / 50% NDF = 30 lbs of forage DM in ration Helps to adjust forage feeding levels based upon harvest maturity, but does nothing to account for digestibility differences Slide Credit: Dr. Tom Overton

4 NDF Digestibility Can be measured either in vitro (in the flask or porous bag) or in situ (in a bag hung in the rumen) In vitro much more common Timepoints usually include 12, 24, 30, or 48 hour incubations Can also look at 120 and 240 h (undigested NDF) If you have NDF and undf information at different timepoints, you can calculate a rate of NDF fermentation (Kd) for use in ration models such as CNCPS Slide Credit: Dr. Tom Overton

5 Slide Credit: Dr. Greg Roth, Penn St.

6 Then and now Corn silage analysis, January 2013 Corn silage analysis, December 2016 Slide Credit: Dr. Tom Overton

7 NDF residue Corn silage example: NDF t Fermentability (energy value) P1+P2+iNDF Intake potential (gut fill) time, hrs Van Amburgh and Zontini, 2015 CNC Slide Credit: Dr. Tom Overton

8 Examples of high and low undf forages Forages andfom, undfom, Fast, %DM %andfom %andfom Alfalfa hay Slow, %andfom Alfalfa silage loundfom Alfalfa silage hiundfom BMR Corn Silage Conv. Corn Silage Zontini and Van Amburgh Slide Credit: Dr. Tom Overton

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10 Slide Credit: Dr. Greg Roth, Penn St.

11 Slide Credit: Dr. Randy Shaver

12 MADRID AURORA

13 Total Tract NDF Digestibility (TTNDFD) prediction Developed by Dr. Dave Combs at University of Wisconsin, Madison Licensed to Rock River Laboratories Uses in vitro analysis of NDF digestibility's at 24, 30, and 48 hours and undf 240 Dr. John Goeser, Rock River Laboratories, September 2016 Slide Credit: Dr. Tom Overton

14 2016 NYS Corn Silage Hybrid Trials Aurora Planted May 12 Madrid Planted May 17 Aurora Lima Silt Loam Madrid Kalurah Fine Sandy Loam

15 Assessing Forage Quality Predicting Milk Yield Past..and present Wisconsin Milk Program (MILK2006) Reported Milk/Ton Milk/Ton * Yield = Milk/Acre Previous NY studies & the majority of other corn silage trials

16 A new approach for 2016 and beyond Predicting Milk Yield Utilizing Cornell Net Carbohydrate and Protein System v What is CNCPS? Dynamic model used to balance feed rations for cattle Under continuous development since 1980 s First applied to on-farm use in the early 1990 s Currently used as the basis for ration software programs that feed more than 40% of the cows in the US and many more cows worldwide.

17 Predicting Milk Yield Utilizing Cornell Net Carbohydrate and Protein System v (NDS platform) Base diet formulated for an ME & MP allowable milk yield of 100 lbs/day 2 nd lactation, 110 DIM, 1585 BW, 3.80% milk fat, 3.20% milk true protein High Corn Silage Diet 28 lbs DM from Corn Silage ~60% Forage in Ration Target: 60 lbs Dry Matter Intake (DMI) CNCPS Feed Library Values Used for base ration NDF digestibility values from 2 year average in Cumberland Valley Analytical Services database for: Corn Silage, Alfalfa Haylage, Straw

18 Predicting Milk Yield Utilizing Cornell Net Carbohydrate and Protein System v (NDS platform) Calculations Predicted ME Allowable Milk Yield for each hybrid using same Dry Matter Intake (DMI) as the base ration Library value for starch digestibility decision for nutrition group due to uncertainty of green samples Replaced Corn Silage (on dry matter basis) in base ration with each hybrid in the trial Calculate expected DMI undf240 equivalent of the base ration Calculate undf240 intake on a DMI equivalent

19 Predicting Milk Yield Utilizing Cornell Net Carbohydrate and Protein System v (NDS platform) undf240 Adjustment Predicted ME Allowable Milk Yield, undf240 equivalent (lbs/day) Adjusted total ration DMI so the undf240 was equal to that in the base ration. Reflects how much the cow actually may be able to consume based on rumen fill.

20 Considerations and Potential Limitations In practice, a dairy nutritionist would make other adjustments to the diet when a new forage is being utilized in the ration. While past approaches may not fully acknowledge the differences in each hybrid, the undf240 adjustment may show a greater difference between hybrids than what will happen in practice. The analysis presented here does not address the potential differences in starch digestibility between hybrids. The model does utilize Total Starch (%) and Starch Digestibility; however, Starch Digestibility is known to be unreliable on green corn samples.

21 Ruminal degradation rates for selected hybrids Hybrid A Hybrid B

22 Story of the Year: Weather Table 1. NYS Corn Silage Trials, 2016 Weather Data Long Term Weather Means Month Precipitation (inches) GDD (86/50 F) Precipitation GDD (86/50 F) Aurora Madrid Aurora Madrid Aurora Madrid Aurora Madrid May June July August Seasonal yr Mean

23 Aurora Relative Maturity Yield, 35% DM Dry Matter Predicted ME Allowable Milk Yield, DMI Equivalent undf240 Intake, DMI Equivalent Adjusted TMR DMI, DMI Equivalent Predicted ME Allowable Milk Yield, undf240 tons/acre % lbs/day lbs/day lbs/day lbs/day CNCPS value CNCPS value CNCPS value CNCPS value day day day Madrid Relative Maturity Yield, 35% DM Dry Matter Predicted ME Allowable Milk Yield, DMI Equivalent undf240 Intake, DMI Equivalent Adjusted TMR DMI, DMI Equivalent Predicted ME Allowable Milk Yield, undf240 tons/acre % lbs/day lbs/day lbs/day lbs/day CNCPS value CNCPS value CNCPS value CNCPS value day day day

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26 On-going work on Digestibility Dairy One Study, Slide Credit: S.A. Flis et al.

27 Corn Plant Development

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29 Using this information Using Public Trials as Comparison Average digestibility numbers will vary by hybrid and year Public trials provide the range in expected values for given growing season Undigested Neutral Detergent Fiber (undf) % of NDF vs. % Dry Matter (DM) Dry Matter Comparisons Suggest only comparing forage data for hybrids within 3% DM of each other Combined Location data more powerful than Individual Location data

30 What s next? Continue to build the understanding of what aspects of forage quality have the most impact on animal performance. Utilize this information for both grower hybrid selection and development of new hybrids in the seed industry Continue to evaluate and refine approach to improve relationship between model predictions and on-farm performance. Seek an equation driven approach to ranking silage hybrids that is more adoptable than individual model runs for each hybrid.

31 2017 NYS & VT Corn Silage Hybrid Trials day RM 23 hybrids planted at 2 locations in NY and 1 location in Vermont day RM 50 hybrids planted at 2 locations in NY and 1 location in Vermont Always looking for way to gain more information from trials 2017 Mycotoxin Screening

32 Thank You! Joe Lawrence, MS, CCA Dairy Forage Systems Specialist Cornell University PRO-DAIRY