Predicting the heating value of solid manure with visible and near-infrared spectroscopy

► Spectral models predicted feedlot manure HHV within 1.7% with excellent reliability. ► Estimated N and S corrections to HHV reduced spectral prediction by 0.1%. ► VisNIR-DRS models reliably predicted HHVdaf based on proximate data within 1.8%. ► Manure-specific HHVdaf equations from ultimate data may improve spectral prediction.