Technical note: Rapid mineral determination in forages by X-ray fluorescence

Area of Science:

• Agricultural Science
• Analytical Chemistry
• Animal Nutrition

Background:

• Forages are a major component of cattle diets, but their mineral content varies significantly, impacting animal health and performance.
• Traditional mineral analysis methods are destructive and labor-intensive, requiring complex procedures for individual mineral quantification.

Purpose of the Study:

• To evaluate the predictive performance of Energy Dispersive X-ray Fluorescence (EDXRF) for quantifying 11 key minerals (Na, Mg, P, S, Cl, Ca, K, Mn, Fe, Cu, Zn) in various forages.
• To establish EDXRF as a simple, direct, and affordable alternative to conventional forage mineral analysis techniques.

Main Methods:

• Developed calibrations using 12 certified plant samples with diverse mineral concentrations.
• Validated the EDXRF method on 35 diverse forage samples (alfalfa hays, grass hays, corn silages) using proficiency program data.
• Utilized a Bruker SpectraEDX instrument, scanning samples at 20 and 40 keV with an Al filter for approximately 6 minutes per sample.

Main Results:

• Achieved acceptable calibration performance for all minerals, with coefficients of determination (R²) ranging from 0.93 (P) to 0.99 (Cl, Ca, Mn).
• Coefficients of variation (CV) were within 5-14% for most minerals, comparable to reference methods, except for Na (29% CV).
• Validation results mirrored calibration performance, indicating robust calibration models applicable across different forage types with minimal bias correction needed for K and Ca.

Conclusions:

• Energy dispersive X-ray fluorescence (EDXRF) is a validated, accurate, direct, and simple technique for multi-mineral analysis in forages.
• EDXRF simplifies forage mineral analysis, supporting improved animal nutrition management and health.
• The method's non-destructive nature and affordability make it a valuable tool for routine forage testing.