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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #399930

Research Project: Sustainable Intensification of Integrated Crop-Pasture-Livestock Systems in Northeastern Landscapes

Location: Pasture Systems & Watershed Management Research

Title: Brix as an indicator of sugar content and nutritive value in alfalfa and orchardgrass herbage

item Billman, Eric
item Soder, Kathy
item HORST, JEFF - Agri-King, Inc
item BALK, KRISTI - Agri-King, Inc
item HAFLA, AIMEE - Cargill Slu, Cargill Animal Nutrition

Submitted to: Grassland International Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/30/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary: Farmers desire rapid, on-farm methods to evaluate nutrient content of forages. Brix, a measure of dissolved solids in solution, is used in the wine industry to determine sugar content of grapes. Some livestock farmers have been using the Brix method to estimate sugar content of forages for grazing, but it is not known whether this is an accurate method. A study was conducted to determine if Brix could predict nutritional value, particularly energy content, of orchardgrass and alfalfa. While Brix did show some promise in predicting fiber and energy content of alfalfa, Brix values for orchardgrass were not useful at predicting sugars or other nutrients. While Brix may prove useful in predicting energy content of forage legumes, it is not a reliable indicator for grasses, and should not be the sole method of determining nutritional value of pasture forages.

Technical Abstract: Brix, a measurement of total dissolved solids in solution, has been used by forage producers to provide real-time estimates of forage energy content. However, its efficacy in forage crops has never been validated through wet chemistry testing and comparisons with other nutritive value parameters. This study compared and correlated Brix measurements with sugar concentrations and common nutritive value parameters relating to protein, fiber, and energy to determine the viability of using Brix to predict when to graze or harvest forages. Brix measurements were collected on alfalfa and orchardgrass samples monthly from May to August in 2019 and 2021. Samples were immediately flash frozen with liquid nitrogen and analyzed for sugar concentration and standard nutritive value components. Brix did not differ among sampling dates for alfalfa and only differed at the May sampling for orchardgrass, indicating that Brix values were not affected by harvest date during late spring and summer months. When correlated across all sampling dates, Brix was positively correlated to sugar concentrations, reduced fiber, and greater net energy concentrations in alfalfa, but not positively correlated to any nutritive value parameters in orchardgrass. These results indicated that Brix should be used only in a limited fashion to predict energy content of forages and is more reliable when used with forage legumes than grasses.