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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #370931
Research Project: Sustainable Intensification of Integrated Crop-Pasture-Livestock Systems in Northeastern Landscapes

Location: Pasture Systems & Watershed Management Research

Title: Assessing the efficacy of in-field brix measurements for forage sugar and energy content

Author
item Billman, Eric
item Soder, Kathy
item HORST, JEFF - Agri-King, Inc
item BALK, KRISTI - Agri-King, Inc
item HAFLA, AIMEE - Agri-King, Inc

Submitted to: Northeast Pasture Consortium Annual Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 1/10/2020
Publication Date: 1/19/2020
Citation: Billman, E.D., Soder, K.J., Horst, J., Balk, K., Hafla, A. 2020. Assessing the efficacy of in-field brix measurements for forage sugar and energy content[Abstract]. Northeast Pasture Consortium Annual Meeting Proceedings. p. 1.

Interpretive Summary: No Interpretive Summary is required for this Abstract Only. JLB.

Technical Abstract: In recent years, some dairy and livestock producers have been using Brix refractometers, which measure the refractive index of dissolved solids, to provide an estimate of forage sugar and energy content without needing to rely on expensive laboratory testing. However, little validation of the Brix Index has been conducted in forage crops, leading some to question the efficacy of the system for forages. The objective of this study was to compare and validate Brix readings with wet chemistry values, and determine if the Brix Index is a reliable way to assess forage sugar content. Four sampling periods occurred on a 25 - 30-day basis between May and August, 2019. At each sampling, eight alfalfa and orchardgrass samples were collected, with three Brix readings per sample measured on a digital Brix refractometer. Samples were flash-frozen, freeze-dried, and analyzed via wet-lab analyses for total and individual sugar concentrations and nutritive value (Agri-King, Inc., Fulton, IL). Brix values were correlated with lab analyses in SAS 9.4. Brix values were either: a) negatively correlated (P < 0.01) to wet-lab analyses of total sugars (-0.65), glucose (-0.64), and fructose (-0.68) in orchardgrass, or b) not correlated (P > 0.2) to total sugars, glucose, and fructose in alfalfa. Conversely, Brix values of both orchardgrass and alfalfa were positively correlated (P < 0.01) to NDF (0.57 – 0.58) and hemicellulose (0.42 – 0.55), along with ADF of alfalfa (0.54). There was no correlation between Brix values and commercially-used metrics for forage quality, including TDN, RFV, and RFQ. These findings indicated that the Brix index is not a reliable way to assess the sugar content of forages. Producers should consider more accurate methods of analysis for assessing energy content of pastures.