Using near Infrared Reflectance Spectroscopy (NIRS) to Estimate In Vitro True Digestibility (IVTD) In Coastal Bermudagrass.

The objective of this study was to develop a near infrared reflectance spectroscopy (NIRS) calibration to predict in vitro true digestibility (IVTD) of Coastal bermudagrass. Coastal bermudagrass samples (n= 240) of varying maturity and quality were obtained and analyzed in duplicate for 48 hour IVTD using an ANKOM Daisy II incubator.  Samples were also analyzed for crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF).  The samples were ordered from low to high IVTD% and split, every other sample, into a calibration set and a validation set.  A calibration was developed using UCal calibration software (Unity Scientific 2010) with the calibration set.  The R² statistic generated within the UCal software for the calibration was 0.87.  This calibration was installed on the NIRS unit and tested with the separate validation set yielding an R² value of 0.62.  Based on this research, it is apparent that NIRS can be calibrated to predict IVTD of Coastal bermudagrass.  Future research should focus on expanding the calibration to include other forage types, and utilizing IVTD values to predict available energy in forages.  Calibrations and validations for moisture, CP, NDF, and ADF will be reported.