Fractional Harvest of Fodder Galega for Improved Herbage Nutritive Value

Abstract

Fodder galega (Galega orientalis Lam.) is a long-lived perennial legume grown for forage and green manure in northern and central Europe. It is distinguished by a high proportion of leaves in the aboveground mass, tall hollow stems, and rhizomes. A method to harvest galega allowing the separation of leaves, upper stem fragments, and inflorescences from the thick, woody parts of the stem is therefore justified. This would significantly expand the possibilities of using galega herbage, including as feed for monogastric animals. A modified flail chopper (MFC), a machine originally used for harvesting green forage, was used for the fractionated harvest of galega. The aim of this study was to evaluate the yield potential of various plant fractions of the first and second cut of fodder galega at three development stages and their nutritive value when harvested with an MFC. With this harvest system, 68–78% of the potential dry matter yield of galega was harvested, where leaves accounted for 73% of the dry matter on average, while the proportion of leaves in the yield of galega harvested with a mower (M) ranged from 50% to 60%. In the biomass of the first cut of galega, harvested with the MFC, protein concentration was 215 g kg−1, 11.5% greater than in the biomass of the whole aboveground mass harvested with a mower. In the second cut, this difference, in favor of the MCF, was greater by 14%. The concentration of neutral detergent fiber (NDF) was 7.5% lower and acid detergent fiber 11% lower in galega forage harvested with the MFC compared to with a mower. Furthermore, galega harvested with MFC had 13% greater NDF digestibility and 6% greater in vitro true digestibility. The stubble remaining after MFC harvest accounted for 33% of the total height and 27% of the plant dry mass, and its qualitative composition indicates that it could be used in rations of livestock with low nutritional requirements or for non-forage purposes. Galega harvest with the MFC resulted in greater protein concentrations and overall improved nutritive value of the forage even at advanced development stages.