A1. Relative Feed Value Index
References:
Rohweder, Dwayne A. 1984. Estimating forage hay quality. In
National Alfalfa Hay Quality Testing Workshop. pp 31-37 Chicago,
IL. March 22-23.
Mertens, David. 1985. Effect of fiber on feed quality for dairy
cows. In Proc. Minnesota Nutrition Conference. pp 204-224.
Linn, J.G. Neal P. Martin, W.T. Howard. and D.A. Rohweder. 1987.
Relative feed value as a measure of forage quality. Minnesota
Forage UPDATE. vol XII, No. 4. pp 2,4. Minnesota Forage and
Grassland Council.
Rohweder, D.A., R.F. Barnes, and Neal Jorgensen. 1978. Proposed
hay grading standards based on laboratory analysis for evaluating
quality. J. Anim. Sci. 47:747-759.
Scope:
Digestible Dry Matter (DDM), Dry Matter Intake (DMI), and
Relative Feed Value Index (RFV) calculations are applicable to
legume, legume-grass and cool season grass fresh forages, hays
and haylages.
Basic Principle:
Relative feed value index is an index which ranks cool season
legumes, grasses and mixtures by potential digestible dry matter
intake. It is an index used to allocate forages to the proper
livestock class with a given level of expected performance.
Relative feed value is calculated from digestible dry matter and
dry matter intake. Digestible dry matter is an estimate of the
total digestibility of the feed and is calculated from acid
detergent fiber. Dry matter intake is an estimate of the amount
of feed an animal will consume in percent of body weight and is
calculated from percent neutral detergent fiber.
Calculation: Relative Feed Value (RFV)
DDM = Digestible Dry Matter = 88.9 - (.779 x
%ADF)
DMI = Dry Matter Intake = 120 / %NDF
RFV = DDM x DMI / 1.29
- %ADF = acid detergent fiber, dry matter basis
- %NDF = neutral detergent fiber, dry matter basis
|