Forage Evaluation Using Various Laboratory Techniques

Publisher Website
Google Scholar
Abstract
Forages from tropical and temperature regions were evaluated by chemical analyses, in vitro rumen fermentation and various enzymatic incubations. Commercial cellulose preparations had differing activities for various cellulose substrates. Cellulose, amylase, pepsin or these enzymes in sequential incubations predicted in vivo digestible dry matter (DDM) of alfalfa or grasses with correlations of .52 to .90 and standard errors of estimate (See) of 2.4 to 5.6. Use of buffer alone approached this accuracy. In vivo DDM of temperate forage was predicted from cell components (cell walls (CW); acid detergent fiber (ADF) or ligin (L)) with correlations of .70 to .86 and See of 3.3 to 5.6. The two stage in vitro fermentation as DM or organic matter disappearance was the method of choice for predicting DDM of both grasses and legumes with See of 1.8 to 4.4 and correlations of .88 to .98. Use of multiple in place of simple linear regression equations using above laboratory values did not appreciably increase prediction accuracy. Temperate forages had greater in vitro dry matter disappearance (IVDMD), crude protein (CP), and lignin than tropical forages examined by ratios of 1.05, 1.28 and 1.14, respectively. These tropical forages were greater than temperate forages by ratios of 1.11, 1.05 and 1.21 for cell walls (CW), acid-detergent fiber (ADF) and ash, respectively. Values for IVDMD and CP of five temperate grasses grown in Michigan decreased with advancing maturity at the rates of .42 and.13 percentage unit per day, whereas those for three tropical grasses grown in Thailand decreased at the lower rates of .09 and .09% unit per day, respectively. Copyright © 1976. American Society of Animal Science . Copyright 1976 by American Society of Animal Science