Forages with condensed tannins - their management and nutritive value for ruminants

Abstract

Temperate forage legumes that contain condensed tannins (CT) have been evaluated under experimental conditions and some have demonstrated significant benefits for sheep, cattle and deer. Condensed tannins can significantly improve productive performance, as well as lessen our dependence on anthelmintic drenches. However, not all CT are equal and some may not benefit production at all. This paper summarises the performance responses of ruminants to CT in birdsfoot trefoil (Lotus corniculatus), lotus (Lotus pedunculatus), sulla (Hedysarum coronarium), sainfoin (Onobrychis viciifolia) and erect dorycnium (Dorycnium rectum), and indicates the requirements for successful establishment and management of these swards. All require specialist care, and few will compete with common pasture species in high-fertility situations, but the potential benefits of reduced anthelmintic requirements when sheep are fed sulla, and the lowered incidence of flystrike and improved weight gain, wool growth, milk production and ovulation rate attributable to the CT in birdsfoot trefoil, makes these attractive options for farmers. Lotus is a high quality feed for wet, acid, low-fertility soils and sainfoin may result in very good stock performance in dry regions. Annual dry matter yields of the five species outlined here range from about 10 to 25 t/ha and some of these forages will benefit producers who are prepared to manage these forages correctly. Keywords: birdsfoot trefoil, condensed tannin, dorycnium, forage legume, lotus, ruminant nutrition, sainfoin, sulla