Laboratory Assays and Near-Infrared Reflectance Spectroscopy for Estimates of Feeding Value of Corn Silage

Abstract

Corn silages samples from the Virginia Tech Forage Testing Program were classified by color, presence or absence of mold, aroma, and fermentation type. In the sample of 142 corn silages, in vitro digestible organic matter averaged 59.8% (range 38.5 to 74.7%) and indicated a range of silage quality. Simple and multiple regression of in vitro digestible organic matter on chemical constituents were derived for the full data set and within fermentation groups. Acid detergent fiber and dry matter explained the largest portion of the variation of digestibility. Simple regression on the full data set had coefficients of determination of .352 and .208 with standard errors of prediction of 5.29 and 5.86 for acid detergent fiber and dry matter. Multiple regression analyses improved coefficient of determination and standard error slightly. Corn silage in vitro digestible organic matter was predicted by near infrared reflectance techniques. A calibration equation resulted in coefficient of determination of .88 and standard error 5.38. The calibration equation was tested for prediction of an additional 90 corn silages. Regression of digestibility predicted by near infrared reflectance resulted in coefficient of determination of .37 and standard error of 4.04. Prediction of corn silage digestibility by near infrared reflectance or laboratory methods was similar. © 1985, American Dairy Science Association. All rights reserved.