March, 1995                                                                                                                PDF Version

Acid Detergent Fiber, Neutral Detergent Fiber Concentration, 
and Relative Feed Value
C.C. Sheaffer, M.A. Peterson, M. McCaslin, J.J. Volenec,
J.H. Cherney, K.D. Johnson, W.T. Woodward, and D.R. Viands

Establishment .................... Uniform stands should be established to provide a minimum of 10 plants/square foot in the year following seeding.
Scheduling of harvests ....... Dormant entries should be sampled at the first three harvests of the season; nondorrnants at the second, fourth and sixth harvest of the season. Fall harvests which occur during a dormancy reaction period should not be used for forage quality determination. Harvests should occur at bud to flower. Visually quantify alfalfa maturity using a 1-8 scale where l=vegetative (stems have no buds or flowers); 2=early bud (1 33% ofthe stems have buds); 3=mid bud (34-65% of the stems have buds); 4=late bud (66-100% of the stems have buds); 5=early flower (1-33% of the stems have flowers); 6=mid flower (34-65% of stems have flowers); 7=late flower (66 100% of stems have flowers); 8=post flower (stems have pods or seeds). Do not adjust forage quality data for maturity. Report data individually for each harvest. Weighted average values across harvests can also be reported. Weighted values are calculated by summing the product of yield x (ADF %, NDF % or RFV) for each sampling before dividing by the number of samplings.
Stand age........................... Sample from stands in the first or second year following the seeding year and which have a minimum of 10 plants/square foot. Results from stands in the seeding year can be used as supporting data but cannot be used to fulfill minimum test year requirements.
Locations............................ Data from a minimum of 2 test years (2 tests at 2 locations in the sarne year or 2 tests at 1 location in 2 years).
Yield................................... Dry matter yield data for the same plots that are sampled for quality is not required but can be provided to augment forage quality data.
Replication.......................... 4 minimurn
Soil fertility......................... Test soil and apply fertilizer and lime to promote high yields.
Soil moisture....................... Maintain to prevent plant water deficit stress and to promote good crop yields.
Pest control......................... Alfalfa should be scouted and insecticides should be applied when needed. The presence and severity of foliar diseases should be recorded.


Sample collection
Forage samples should be obtained from non-border areas of plots. Samples should be taken by hand clipping a minimum of 3 square feet per plot. If plots are not uniform, hand grab samples should be taken from multiple locations within a plot. It is unacceptable to collect forage samples from a flail-type harvester. Minimum sample size should be 300 g wet weight. Samples should be taken to a 5 cm stubble height.

Sample preparation
Dry samples at 120 to 140° F in a forced air oven in less than 48 hr. For drying; cloth, perforated paper bags, or trays can be used. Grind samples to pass a 1 mm screen.

Laboratory tests
Quality evaluation is based on deterrnination of neutral detergent fiber (NDF, for intake), and in vitro digestible dry matter or acid detergent fiber (ADF, for digestibility) using wet chemistry or near infrared reflectance spectroscopy (NlRS). For both wet laboratory and NIRS procedures, it is assumed that procedures used have accuracy and precision required for scientific publication. Relative feed value is calculated using the following equations:


and where % DDM (digestible dry matter)=88.9 - (.779 x ADF %)

% DMI (dry matter intake)

=              120          
        Forage NDF (% of DM)      

Crude protein data can be included in a description of cultivar forage quality, but should be used only when accompanied by flber and RFV data.


High quality: WL 322 HQ, Pacesetter, or Cimmaron VR
Low quality: Vernal
In a national test conducted over eight locations, Pacesetter, Cimmaron VR and WL 322 HQ averaged about 2% lower NDF and 1% lower ADF than Vernal when harvested at bud to flower maturity.
High and low quality checks for nondormant alfalfa cultivars will be described when data become available.


Name .........Craig C. Sheaffer
Address ..... Dept of Agronomy and Plant Genetics
                   411 Borlaug Hall
                   1991 Upper Buford Circle
                   University of Minnesota
                   St.Paul,MN 55108
Phone ........ 612-625-7224

Name ........ Michael A. Peterson
Address .....W-L Research Inc.
                  8701 Hwy. 14
                  Evansville, WI 53536-9593
Phone ........608-882-4100

Name .........Mark McCaslin
Address ......Forage Genetics
                   5292 Gills Coulee
                   West Salem, WI 54669
Phone .........608-786-2121


 Relative feed value (RFV) describes digestible energy intake potential of forages and can be used for comparison of relative forage quality of alfalfa cultivars. However, the relationships between intake and digestibility assumed in RFV calculation may not be applicable to all types of livestock.


 For more accurate and precise determination of alfalfa maturity, maturity can be quantified using the mean stage by count or mean stage by weight methods (2).


1.   Goering, H.K., and P.J. Van Soest. 1970. Forage fiber analyses (apparatus, reagents, procedures, and
      some application). USDA Handbook 379, U.S. Gov. Print. Office, Washington, DC.

2.   Fick, G.W, and S.C. Mueller. 1989. Alfalfa quality, maturity, and mean stage of development. Cornell
      University Iformation Bull. 217.

3.   Linn, J.G., and N.P. Martin. 1989. Forage quality tests and interpretation. Minnesota Extension Service.
      AG FO-2637.

4.   Mueller, S.C., and G.W. Fick. 1989. Converting alfalfa development measurements from mean stage by
      count to mean stage by weight. Crop. Sci. 29:821-823.

5.   Shenk, J.S., M.O. Westerhaus, and S.M. Abrams. 1989. Protocol for NIRS calibration: monitoring analysis
      results and recalibration. p. 104-110. In G.C. Marten, J.S. Shenk, and F.E. Barton (ed). Near Infrared
      Reflectance Spectroscopy (NIRS): Analysis of forage quality. USDA ARS Handbook 643, U.S. Gov. Print.
      Office, Washington, DC.

6.   Smith, Dale. 1973. Influence of drying and storage conditions on nonstructural carbohydrate analysis of
      herbage tissue-A review. J. British Grassland Soc. 28:129-133.

7.   Stucker, R.E., and C.C. Sheaffer. 1991. Sampling procedures for predicting quality of alfalfa. p. 190. In
      Agronomy Abstracts. ASA, Madison, WI.

8.   Undersander, D.J., B.E. Anderson, and N.P. Martin. 1991. Determining forage quality of alfalfa varieties. 
      p. 191. In Agronomy Abstracts. ASA, Madison, Wl.

9.   Volenec, J.J., J.H. Cherney, and K.D. Johnson. 1987. Yield components, plant morphology, and forage
      quality of alfalfa as influenced by plant population. Crop Sci. 27:321-326.

10. Windham, W.R., D.R. Mertens, and F.E. Barton. 1989. Protocol for NIRS calibration: sample selection
      and equation development and validation. p. 96-103. In G.C. Marten, J.S. Shenk, and F.E. Barton (ed).
      Near Infrared Reflectance Spectroscopy (NIRS): Analysis of forage quality. USDA, ARS Handbook 643,
      U.S. Gov. Print. Office, Washington, DC.

11. Wolf, D.D., and T.L. Ellmore. 1975. Oven drying of small herbage samples. Agron. J. 67:571-574.

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