Digestibility and Feeding value of Fodder Galega (Galega orientalisLam.)

Abstract

Abstract The objectives were to study fodder galega concerning (1) its composition, digestibility and feeding value, (2) the relationship between the concentration of in vitro organic matter disappearance (IVOMD) and the concentration of in vivo digestibility of organic matter (DOM), and between the concentration of gross energy (GE) and DOM and the concentration of digestible energy (DE), and (3) the difference between DE calculated on basis of chemical composition of DOM and in vivo DE. The study was based on digestibility trials with sheep on 17 samples of fodder galega in connection with a harvest management experiment in which cutting frequency and time of first harvest varied. The main results were, first, that the concentration of crude protein, DOM (in vivo), DE (in vivo) and feed units for cattle (FUC) decreased by delaying harvest of the first cut. The concentration of fibre expressed as crude fibre, neutral detergent fibre (NDF) and acid detergent fibre (ADF) increased by delaying harvest at the first and following cuts. Fodder galega differed from other legumes not included in this study by having a higher concentration of hemicellulose calculated as NDF-ADF, while the mean concentration of DE (in vivo) and FUC was nearly equal to the mean concentration in red clover, winter vetch and yellow lupins. Secondly, DOM in fodder galega may be predicted by using an equation based on the concentration of IVOMD, and DE in fodder galega may be predicted by using another equation based on the concentrations of GE and DOM. The two equations were developed on the basis of this investigation of fodder galega. Thirdly, DE predicted on the basis of the chemical composition of DOM in fodder galega deviated considerable from in vivo DE. The conclusions were that the chemical composition, digestibility and feeding value of fodder galega changed when the yield increased by delaying harvest, especially at the first cut.