Description

Brix, a measurement of total dissolved solids in solution, has been used by forage producers to provide real-time estimates of energy content of fresh herbage. However, its efficacy has never been validated in herbage 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 fresh herbage. Brix measurements were collected monthly on fresh herbage samples of alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.) from May to August in 2019 and 2021. Herbage was immediately flash frozen with liquid nitrogen and analyzed for sugar concentration and nutritive value. 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 fresh herbage and is more reliable when used with legumes than grasses.

Share

COinS
 

Brix as an Indicator of Sugar Content and Nutritive Value in Alfalfa and Orchardgrass Herbage

Brix, a measurement of total dissolved solids in solution, has been used by forage producers to provide real-time estimates of energy content of fresh herbage. However, its efficacy has never been validated in herbage 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 fresh herbage. Brix measurements were collected monthly on fresh herbage samples of alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.) from May to August in 2019 and 2021. Herbage was immediately flash frozen with liquid nitrogen and analyzed for sugar concentration and nutritive value. 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 fresh herbage and is more reliable when used with legumes than grasses.