using digestible ndf to determine forage quality l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Using Digestible NDF to Determine Forage Quality PowerPoint Presentation
Download Presentation
Using Digestible NDF to Determine Forage Quality

Loading in 2 Seconds...

play fullscreen
1 / 31

Using Digestible NDF to Determine Forage Quality - PowerPoint PPT Presentation


  • 623 Views
  • Uploaded on

Using Digestible NDF to Determine Forage Quality Dr. Dan Undersander University of Wisconsin Importance of Digestible Fiber Use of empirical equations For many years we estimated forage energy content from single analyte Sampling of Empirical equations From Western Region

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Using Digestible NDF to Determine Forage Quality' - Pat_Xavi


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
using digestible ndf to determine forage quality
Using Digestible NDF to Determine Forage Quality

Dr. Dan Undersander

University of Wisconsin

importance of digestible fiber
Importance of Digestible Fiber
  • Use of empirical equations
    • For many years we estimated forage energy content from single analyte
sampling of empirical equations
Sampling of Empirical equations
  • From Western Region
    • %TDN = 82.38 - (0.7515 x ADF)
  • From Pennsylvania
    • %TDN = 4.898 + (89.796 x NEL)
    • NEL (Mcal/lb) = 1.044 - (0.0119 x ADF)
  • From Midwest
    • %DDM = 88.9 - (0.779 x ADF)
nrc 2001 dairy approach to predicting tdn of forages
NRC (2001) Dairy Approach to Predicting TDN of Forages
  • Uniform feed fractions will have predictable digestion coefficients

TDN 1-X =tdCP + (tdFAx 2.25) + tdNDF + tdNFC -7

  • A more accurate and robust way to estimate TDN of forages than ADF
  • TDN values estimated by NRC(2001) are different than what we are used to.
slide8

Influence of NDF digestibility on forage digestibility

TDN = tdCP + (tdFA x 2.25)+ (.75 x NDFD48 x NDF)+ tdNFC -7

NDF ADF NDFD48TDN DDM*

Forage A: 40 30 5861.6 65.5

Forage B: 40 30 3653.6 65.5

*DDM = 88.9 * .779(ADF)

slide9

Influence of NDF digestibility on dry matter intake

dIntake = base intake plus adjustment for dNDF

= base intake + (NDFD-average NDFD) * .374)

Oba and Allen, 1999. J. Dairy Sci. 82:589-596

NDF ADF NDFDdIntake DMI*

Forage A 40 30 5831.0 2.78% of BW

Forage B 40 30 3622.8 2.78% of BW

*DMI = 120/NDF

slide10

Adjusting DMI, Base TMR

Lb DM

Alfalfa 20-30-40-58 25

Corn silage 6

HMC 20

Protein/mineral/vitamins 7

DMI 58

NRC 2001 ration evaluation (110 lb milk)

NE allowable milk, lb 93

MP allowable milk, lb 110

NEl balance, Mcal - 5.6

TMR Nel, Mcal/lb .70

slide11

Suppose alfalfa

composition changed

to 20-30-40-36:

Impact:

TDN

61.6 -> 53.6

dIntake

31.0 ->22.8

Action steps

Change alfalfa TDN in

ration program

Discount TMR intake

.374(58-36) = 8 lb

Adjusting DMI, Base TMR

Lb DM

Alfalfa 20-30-40-58 25

Corn silage 6

HMC 20

Protein/mineral/vitamins 7

DMI 58

NRC 2001 ration evaluation

NE allowable milk, lb 93

MP allowable milk, lb 110

NEl balance, Mcal - 5.6

TMR Nel, Mcal/lb .70

slide12

Adjusting DMI and TDN

Base TMR Adjusted TMR

20-30-40-58 20-30-40-36

Alfalfa 25 22

Corn silage 6 5

HMC 20 17

Protein/mineral/vitamins 7 6

DMI 58 50

NRC 2001 ration evaluation

NE allowable milk, lb 93 83

MP allowable milk, lb 110 91

NEl balance, Mcal - 5.6 -8.7

TMR Nel, Mcal/lb .70 .73

slide13
Relative Feed Value =

(Intake Potential * Digestible DM)

Constant

slide14
Relative Feed Value (Current)

Intake Potential = 120/NDF

Digestible DM = 88.9 - (0.779*ADF)

Constant = 1.29

slide15
Relative Feed Value (Current)

Intake Potential = 120/NDF

Digestible DM = 88.9 - (0.779*ADF)

Constant = 1.29

slide16
Relative Forage Quality (RFQ) =

(dIntake Potential * dTDN)

Constant

relative forage quality
Relative Forage Quality

Intake potential

= base intake plus adjustment for dNDF

= base intake + ((dNDF-average dNDF) *.374)

=(0.012/NDF) + (NDFD-45)*0.374*1350/100

From Oba and Allen, 1999, J Dairy Sci

relative forage quality18
Relative Forage Quality

Total Digestible Nutrients (dTDN)

= dNFC + dCP + dFA*2.25 + dNDF - 7

= [(NFC*.98) + (CP*.93) + (FA*.97*2.25) +

NDF * NDFD] - 7

From NRC, 2001

relative forage quality rfq
Relative Forage Quality (RFQ)

RFQ = dIntake potential*dTDN

1.23

slide22

Giving Energy Away

Dissatisfied Customers

relationship of rfv to rfq in alfalfa world s forage superbowl 2003
Relationship of RFV to RFQ in Alfalfa, World’ s Forage Superbowl, 2003

Above line –

* energy not valued

Below line –

* poor animal performance

* dissatisfied customers

* heat damaged samples

summary
Summary
  • Digestible fiber more accurately predicts animal performance on forage than ADF.
  • RFQ uses TDN and digestible fiber.
  • RFQ will more accurately index value of hay to animals.
effect of forage quality on 4 fat corrected milk at four concentrate levels
Effect of forage quality on 4% fat corrected milk at four concentrate levels

From Kawas et al. 1989

effect of forage quality on butterfat content of milk at four concentrate levels
Effect of forage quality on butterfat content of milk at four concentrate levels

From Kawas et al. 1989

value of milk from forage quality
Value of milk from forage quality

From Kawas et al. 1989

value of high quality hay
Value of high quality hay
  • Increased energy content
  • Increased intake
  • Use above 150 RFQ to mix with low quality
    • Values low quality forage that may be on hand
    • May be difficult to mix two hays in some operations
  • Use above 150 RFQ to mix with corn silage
    • Value to protein because corn silage is lower in protein
    • Value to low NDF because corn silage is higher in fiber
further information
Further Information

www.uwex.edu/ces/forage