Laboratory Analyses and Near Infrared Reflectance for Predicting In Vitro Digestibility of Rye Silage

Abstract

In vitro dry matter digestibilities were determined for 62 rye silages selected from samples analyzed by the Virginia Tech Forage Testing program. Results from seven standard analyses and digestibility estimates from near infrared reflectance data (Neotec FQA51)1 were tested for predicting in vitro digestibility of rye silage. The best single predictor of digestibility was acid detergent fiber with a coefficient of determination of .70 and standard error of estimate of 4.95. Inclusion of crude protein and crude protein plus calcium improved prediction (coefficients of determination .75 and .77). Prediction by near infrared reflectance resulted in a coefficient of determination of .59 and standard error of 6.7. Acid detergent fiber or acid detergent fiber plus crude protein would be useful predictors of rye silage digestibility. With software and calibration procedures provided by the manufacturer, the near infrared reflectance technique has limited capability for predicting digestibility of rye silage. Coefficients of determination (.79, .85) and standard errors (1.26, 3.26) for crude protein and acid detergent fiber indicate near infrared reflectance could be employed for predicting these components. © 1984, American Dairy Science Association. All rights reserved.