Beneficial Effects of Temperate Forage Legumes that Contain Condensed Tannins

Abstract

Abstract:The two temperate forage legumes containing condensed tannins (CT) that promote ruminant production are birdsfoot trefoil (Lotus corniculatus L.; BFT) and sainfoin (Onobrychis viciifolia Scop.; SF). Both are well-adapted to the cool-temperate climate and alkaline soils of the Mountain West USA. Condensed tannins comprise a diverse family of bioactive chemicals with multiple beneficial functions for ruminants, including suppression of internal parasites and enteric methane. Birdsfoot trefoil contains 10 to 40 g·CT·kg DM.Our studies have focused on these two plant species and have demonstrated consistently elevated rates of gain for beef calves grazing both BFT and SF. Novel results from our BFT research include carcass dressing percentages and consumer sensory evaluations equivalent to feedlot-finished steers and significantly greater than grass-finished steers, but with omega-3 fatty acid concentrations equal to grass-finished beef. We have further demonstrated that ruminants fed BFT or SF will consume more endophyte-infected tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) forage or seed than ruminants fed a non-CT forage legume. There is great potential value for sustainable livestock production in the use of highly digestible, nitrogen-fixing legumes containing tannins demonstrated to improve ruminant productivity. OPEN ACCESSAgriculture 2015, 5 476

Benefits of Condensed Tannins in Forage Legumes Fed to Ruminants: Importance of Structure, Concentration, and Diet Composition

“…The current evidence suggests that only four forage legumes-birdsfoot trefoil, sainfoin, sulla and crownvetch [Securigera varia (L.) Lassen]-support higher ruminant growth rate or milk yield when fed as a sole diet, compared with CT-free diets (Burns et al, 1972;Waghorn et al, 1990Mueller-Harvey, 2006;Rochfort et al, 2008;Waghorn, 2008;Patra and Saxena 2010;MacAdam et al, 2011;Naumann et al, 2013;Piluzza et al, 2014;MacAdam and Villalba 2015). However, other CT forage legumes or some CT browse species may be beneficial when fed as part of a diet (e.g., lotuses; Ayres et al, 2006).…”

“…Legume swards expressing CTs can be grazed safely, as they are nonbloating (Wang et al, 2012;MacAdam and Villalba, 2015), but optimal use of CT forages would most likely be as a substitute for existing legumes in mixed swards, such as white clover with ryegrass (Lolium L.). This is because dry matter yields are greater from grasses than from legumes (subject to adequate nitrogen availability), and because farmers in temperate climates have identified forage species (including grasses) that enable profitable farming.…”

“…In addition to the constraints mentioned above (dietary crude protein concentration, or whether other nutrients are limiting production), variations in CT traits within germplasms may also affect animal responses . Birdsfoot trefoil has delivered good growth rates in the United States and New Zealand, and the PC/PD ratios were ~80:20 MacAdam and Villalba, 2015). Birdsfoot trefoil has delivered good growth rates in the United States and New Zealand, and the PC/PD ratios were ~80:20 MacAdam and Villalba, 2015).…”

Forage Plant Ecophysiology: A Discipline Come of Age

“…In this volume, performance data for animals fed grass or concentrate diets are compared with those for animals fed birdsfoot trefoil. Of note are findings that, for animals whose diet comprised birdsfoot trefoil, carcass dressing out % at slaughter was increased, and meat flavour score in a taste panel test was enhanced compared to the results for animals fed grass, and comparable to the results for animals fed mixed ration diets [10].…”

“…CT can chemically bind with dietary protein, leading to a 'rumen bypass' effect, reducing enteric methane emissions and increasing the quantity of protein that is absorbed from the intestines [10]. L. corniculatus is well-adapted to cultivation under irrigation in climates with warmer summers, colder winters, and alkaline soils found in the Intermountain West region of the USA.…”