Forage Quality Analysis of Annual Ryegrass Via Near Infrared Reflectance Spectroscopy.

Knowledge of forage nutrient content is fundamental for marketing and selling hay. Accuracy of nutrient content and digestibility traits are also important to livestock producers that feed hay.  Fourier transform near infrared reflectance spectroscopy (FT-NIRS) is a tool capable of quickly measuring or predicting the nutritional value of forage samples, minimizing cost and time compared to older methods.  Accurate FT-NIRS calibration curves (regression models) provide an alternative to traditional chemical analyses, which are laborious in nature and time consuming.  However, limited research has been completed using the Bruker™ FT-NIRS on cool season annual grasses for predicting forage quality components.  The development of a regression equation to determine the relationship of accepted wet chemistry methodologies with results from the Bruker FT-NIRS will allow for rapid and consistent FT-NIRS quality analyses of cool season annual grasses, providing benefits to both hay and livestock producers.

An established annual ryegrass (Lolium multiflorum) paddock was topdressed with three rates of N (0, 84, and 168 kg ha^-1) using 21-0-0, applied in early February in a randomized block design with three replications of each N rate.  Samples were collected on six dates from February to May, dried, ground, and analyzed with both traditional wet chemistry and the Bruker FT-NIRS in order to establish regression models for crude protein, acid detergent fiber, neutral detergent fiber, calcium and phosphorus content.  Using FT-NIRS instrumentation, final results should provide forage testing laboratories with an accurate and cost-effective analysis of cool season annual grasses.