Use of LOCAL algorithm with near infrared spectroscopy in forage resources for grazing systems in Colombia

Abstract

This study used a total of 2020 Colombian forage resources of three families (Grass forages, legume forages, and other forage plants) to develop near infrared spectroscopy calibrations for predicting the nutritional value. Spectra were collected at 2 nm increments using a scanning visible/near infrared spectrometer. The reference data used for each forage were crude protein, crude ash, neutral detergent fiber, acid detergent fiber, acid detergent lignin, measured according to the Association of Official Analytical Chemists. Two chemometric tools for developing near infrared spectroscopy prediction models were compared: the GLOBAL modified partial least squares, and the calibration strategy known as LOCAL. The LOCAL procedure is designed to select, from a large database, samples with spectra resembling the sample being analyzed. Selected samples were used as calibration sets after one-tenth of the samples were selected for validation from each database. Predictions of nutrition indicators in validation samples using generic and specific calibrations were compared with both GLOBAL and LOCAL procedures. For all predicted forages, LOCAL resulted in a significant improvement in both standard error of prediction and bias values compared with GLOBAL. Determination coefficient values (r 2) also improved using the LOCAL algorithm, exceeding 0.9 for most forage sets. LOCAL calibration was then used with only one database (n 2020) comprising all the forage samples and SEP and r 2 were similar to those obtained in the three databases using LOCAL algorithm. Therefore, LOCAL can accurately predict the composition of different forages using only one database, and could offer a practical way to develop robust equations taking into account the biodiversity of Colombian forages.

Productividad y valor nutricional de forraje de cebada y trigo del trópico alto colombiano

“…Las muestras compuestas por hojas y tallos se secaron y conservaron para posterior análisis en el laboratorio. La concentración de proteína cruda (PC), fibra en detergente neutro (FDN), fibra en detergente ácido (FDA), cenizas (CEN), calcio (Ca) y fósforo (P) se determinaron a través de la metodología NIRS (Ariza-Nieto et al, 2017). Además, se calculó la concentración de nutrientes digestibles totales (NDT) y energía neta de lactancia (EN L ) de cada accesión (Adams, 1994).…”

Effect of altitude and defoliation frequency in the quality and growth of Kikuyu grass (Cenchrus clandestinus)

“…Pasture nutritional quality: Dry samples of each plot were ground to a particle size of 0.2 mm in a Wiley type blade mill. Crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and gross energy (GE) in forage samples were determined using Near-Infrared Reflectance Spectroscopy (NIRS) in a FOSS-DS2500 spectrometer (Denmark), with equations validated by the correlation of wet chemistry data of Kikuyu with the scanning of absorption of the samples in the spectrophotometer (NIRS) (Ariza-Nieto et al, 2017). In vitro dry matter digestibility (IVDMD) was determined using the methodology of Tilley and Terry (1963).…”

Productividad de vacas lecheras suplementadas con ensilaje de haba alpargata o remolacha forrajera

“…En el Cuadro 1 se presenta la composición nutricional de la mezcla de las gramíneas y de los ensilajes empleados, los cuales fueron obtenidos mediante la técnica de espectroscopia de reflectancia en infrarrojo cercano NIRS (NIRS DS 2500 -FOSS Analytical A/S -Dinamarca) (Ariza et al, 2017), con base en los métodos de referencia: proteína cruda (PC) (AOAC984.13), fibra en detergente neutro (FDN) (AOAC2002.04), fibra en detergente ácido (FDA) (AOAC973.18), lignina (LIG) (se determinó a partir del residuo insoluble del detergente ácido tratado con ácido sulfúrico 12 M), hemicelulosa (HEM) (diferencia entre FDA y FDN), digestibilidad (DIG) y energía neta de lactancia (ENL) (mediante ecuaciones elaboradas por el laboratorio).…”