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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #143389
Title: CONDENSED TANNIN CONCENTRATION OF RHIZOMATOUS AND NON-RHIZOMATOUS BIRDSFOOT TREFOIL IN GRAZED MIXTURES AND MONOCULTURES

Author
item WEN, LIAN - UNIV OF MISSOURI
item ROBERTS, CRAIG - UNIV OF MISSOURI
item WILLIAMS, JAMES - UNIV OF MISSOURI
item KALLENBACH, ROBERT - UNIV OF MISSOURI
item Beuselinck, Paul
item MCGRAW, ROBERT - UNIV OF MISSOURI

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2002
Publication Date: 1/1/2003
Citation: WEN, L., ROBERTS, C.A., WILLIAMS, J.A., KALLENBACH, R.L., BEUSELINCK, P.R., MCGRAW, R.L. CONDENSED TANNIN CONCENTRATION OF RHIZOMATOUS AND NON-RHIZOMATOUS BIRDSFOOT TREFOIL IN GRAZED MIXTURES AND MONOCULTURES. CROP SCIENCE. 2003. v. 43. p. 302-306.

Interpretive Summary: Birdsfoot trefoil (Lotus corniculatus L.) is a commonly grown herbage legume in pastures of the United States. Trefoil can produce phenolic compounds called condensed tannins that can be beneficial or detrimental to grazing animals depending upon the amount produced. It is known that a small amount of condensed tannins can improve protein utilization by grazing animals, while large amounts can inhibit protein availability and can inhibit feeding. In this study we examined two morphologically different forms of birdsfoot trefoil to determine condensed tannin concentration in the herbage of birdsfoot trefoil without rhizomes (BFT) and with rhizomes (RBFT) from grazed monocultures and mixtures. Experiments conducted in the field demonstrated that condensed tannin concentrations of grazed BFT were lower in this study than concentrations reported in other studies. Averaged over two years, BFT contained 11.4 g of condensed tannins per kg of dry matter, and RBFT contained three times that amount (38.6 g condensed tannins per kg of dry matter). Also, condensed tannin concentrations of the BFT component were 100% higher in 1998 when BFT was grown in a mixture instead of a pure stand; in 1999, they were 55% higher. It was concluded that the condensed tannin concentrations of birdsfoot trefoil were low enough to still be beneficial to protein availability without affecting palatability by grazing animals. This information is important to researchers attempting to understand the ecology of these birdsfoot trefoil forms in interactions with animals, insects, and diseases.

Technical Abstract: Condensed tannins in forage legumes can be beneficial or detrimental to ruminant livestock performance, depending on concentration. The objective of this research was to determine condensed tannin concentration in birdsfoot trefoil (Lotus corniculatus L.) without rhizomes (BFT) and with rhizomes (RBFT) from grazed monocultures and mixtures. An additional objective was to investigate possible fluctuation of condensed tannin concentrations through the spring grazing season. In 1997, "Norcen" BFT and "ARS-2620" RBFT were sown into pastures located at Columbia, MO; pastures were pure stands or mixtures with tall fescue (TF; Festuca arundinacea Schreb). Pastures were grazed in 1998 and 1999, and the BFT and RBFT components were hand-clipped every 14 d throughout the spring of 1998 and 1999. Samples were analyzed for condensed tannin concentration by near infrared reflectance spectroscopy with calibrations based on the vanillin¿HCl colorimetric method. Condensed tannin concentrations of grazed BFT were lower in this study than concentrations reported in other studies. Averaged over both years, BFT contained 11.4 g catechin equivalents (CE)/kg/dry matter, and RBFT contained (P < 0.05) three times that amount (38.6 g CE/kg/dry matter). Also, condensed tannin concentrations of the BFT component were 100% higher when BFT was grown in a mixture instead of a pure stand (P < 0.10); in 1999, they were 55% higher (P < 0.05). Finally, condensed tannin concentration fluctuated over the spring of 1998 (P < 0.05), but not the spring of 1999. We concluded that condensed tannins in BFT are much lower than in RBFT, that condensed tannins in BFT decrease when grown with a tall fescue companion grass, and that concentrations can fluctuate.