Suppression of Standard Forage in vitro Dry Matter Disappearance by Acetone, Methanol, and Aqueous Extracts from Crownvetch Leaflets1

Abstract

Residues from crownvetch (Coronilla varia L.) leaflets were obtained from evaporation of acetone, methanol, and aqueous extracts and added to standard forages to evaluate a previously observed negative relationship between crownvetch in vitro dry matter disappearance (IVDMD) and anti‐quality substances. The activity of the residue was characterized by changes in the IVDMD of the standard forages. Leaflets were selected to represent forage that previously showed high IVDMD and low total phenols (clone 2); low IVDMD and high total phenols (clone 4) and intermediate IVDMD and high total phenols (clone 6). When equal volumes of the residues (dissolved in water) were added to standard forages, only those from methanol significantly reduced the standard forage IVDMD. These residues also ranked the standard forage IVDMD identical to that of the leaflet IVDMD (clone 4 less than clones 6 or 2 and clone 6 higher than clone 4, but less than clone 2).The addition of increasing quantities of each residue to a standard forage revealed that all residues, when added in sufficient concentration, contained the anti‐quality substance(s). When changes in the IVDMD of the standard forage were related to the total phenol concentrations of the methanol residues a high, negative correlation was obtained. The total phenol fraction appeared to be a good index to anti‐quality substance(s) in the methanol residues.Breeding programs with objectives to improve persistence and yield of crownvetch should consider the negative relationship between certain total phenol fractions and IVDMD. Variation exhibited among clones in this character may provide a useful tool for selecting varieties low in anti‐quality substances as reflected by total phenol concentrations.