INFLUENCE OF TEMPERATURE ON CHEMICAL COMPOSITION AND IN VITRO DRY MATTER DISAPPEARANCE OF NORMAL- AND LOW-TANNIN SERICEA LESPEDEZA

Abstract

A normal and a low-tannin sericea lespedeza (Lespedeza cuneata (Dumont) G. Don.) cultivar were grown in controlled environments under a warm (32/24 °C) or cool (22/17 °C) temperature regime. Both cultivars accumulated more dry matter at the higher temperature. The normal-tannin sericea contained a higher concentration of tannin, and lower concentrations of crude protein and neutral detergent fiber (NDF than the low-tannin sericea. Tannin concentration in the leaves of the normal-tannin cultivar was 10 percentage units greater and crude protein and NDF were each 3 units lower at 32/24 °C than at 22/17 °C. Tannin concentration in the leaves of the low-tannin cultivar was 2 percentage units higher, crude protein was 3 units lower, and NDF was 3 units higher at 32/24 °C than at 22/17 °C. In vitro dry matter disappearance (IVDMD) of the normal-tannin leaves was approximately 20 percentage units less than that of the low-tannin leaves, and was not influenced by temperature. Stems were more digestible than the leaves in both cultivars, but normal-tannin stems were slightly less digestible than the low-tannin stems. The IVDMD of low-tannin stems was 6 units lower at 32/24 °C than at 22/17 °C. Future breeding efforts with low-tannin sericea should place emphasis on lower tannin and NDF concentrations because both these components tend to increase with temperature and bear negative associations with IVDMD.Key words: Lespedeza cuneata, neutral detergent fiber, crude protein, forage quality