Condensed tannins bioactivity and nutritional value of Bauhinia cheilantha (Bong) Steud. under sheep grazing and different forage allowances

Abstract

Semiarid rangeland plays an important multifunctional agricultural system and plant nutritive value can vary according to soil and climate conditions, and land use such as grazing pressure. This study investigated the impact of four forage allowances (2, 2.5, 3 and 3.5 kg dry matter per kg body weight) on condensed tannin biological activity and nutritional value of Bauhinia cheilantha (Bong) Steud.). The experiment was conducted in a manipulated shrub-tree tropical rangeland under sheep grazing in a two-year field trial, during the rainy season. Forage allowance and time influenced condensed tannin biological activity and nutritional value. B. cheilantha with up to 167 g kg−1 condensed tannins inhibited up to 38.3% rumen methane, indicating possible sheep metabolizable energy intake increases and also reduced up to 29% larval motility, which may reduce gastrointestinal parasite infections. B. cheilantha nutritional values vary over years and have a negative relationship with forage allowance. Forage allowance can be manipulated depending on management goals as forage or environmental mitigation. Low forage allowance promotes great condensed tannins which impacts on great larval motility and less methane production, but great nutritive value. The findings suggest that the legume B. cheilantha can contribute to meeting the nutritional requirements of ruminants.