In vitro digestibility of mountain‐grown irrigated perennial legume, grass and forb forages is influenced by elevated non‐fibrous carbohydrates and plant secondary compounds

Abstract

BACKGROUND Perennial legumes cultivated under irrigation in the Mountain West USA have non‐fibrous carbohydrate (NFC) concentrations exceeding 400 g kg−1, a level commonly found in concentrate‐based ruminant diets. Our objective was to determine the influence of NFC concentration and plant secondary compounds on in vitro rumen digestion of grass, legume and forb forages compared with digestion of their isolated neutral detergent fiber (NDF) fraction. Forages were composited from ungrazed paddocks of rotationally stocked, irrigated monoculture pastures between May and August 2016, frozen in the field, freeze‐dried, and ground. RESULTS The maximum rate (RMax) of gas production was greater for the legumes alfalfa (ALF; Medicago sativa L.) and birdsfoot trefoil (BFT; Lotus corniculatus L.) than for the legume cicer milkvetch (CMV; Astragalus cicer L.) the grass meadow brome (MBG; Bromus riparius Rehm.) and the non‐legume forb small burnet (SMB; Sanguisorba minor Scop.), and intermediate for the legume sainfoin (SNF; Onobrychis viciifolia Scop.). The RMax of isolated NDF was greatest for BFT and CMV, intermediate for ALF, SNF and SMB and least for MBG. CONCLUSIONS More than 900 g of organic matter kg−1 dry matter of legumes was digested after 96 h. Across forages, the extent of whole‐plant digestion increased with NFC and crude protein concentrations, decreased with NDF concentrations, and was modulated by secondary compounds. The extent of digestion of isolated NDF decreased with concentration of lignin and residual tannins. © 2020 Society of Chemical Industry

Beef Steer Performance on Irrigated Monoculture Legume Pastures Compared with Grass- and Concentrate-Fed Steers

“…The elevated level of readily digested carbohydrates combined with the protection of soluble protein from digestion in the rumen appeared in this study to result in greater ADG for steers grazing BFT than either CMV or a high-quality grass. Cicer milkvetch has been found to contain a water-soluble arabinogalactan protein that prevents cellulolytic bacteria from adhering to cellulose [39,40], which likely reduced the maximum rate of in vitro fermentation of CMV relative to BFT in this and other studies [41].…”

Impacts of red clover and sainfoin silages on the performance, nutrient utilization and milk fatty acids profile of ruminants: A meta‐analysis

“…As sainfoin contains moderate to high percentage of CT, it may affect palatability and also reduce nutrient digestibility due to its binding ability effect (Scharenberg, Arrigo, Gutzwiller, Soliva, et al, 2007). Numerous in vitro studies also demonstrated that sainfoin had lower gas production, degradable DM and OM and VFA production (Copani et al, 2015;Grosse Brinkhaus et al, 2017;Wang et al, 2022) and also NDF digestibility (Zhang et al, 2021) compared to alfalfa and grass.…”

Estimating nutrient composition and polyphenol concentration using Near-Infrared Spectroscopy (NIRS) in tropical forages

“…Forage is the primary source of feed for fulfilling the nutrient requirements of ruminants, including grasses, legumes, and herbs. In addition, this feed plays an essential role in providing dietary fiber, energy, protein, as well as essential vitamins and minerals (Zhang et al 2020). Several studies have shown that the quality of forages can be assessed using their nutritive value, particularly Crude Protein (CP), Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF), Acid Detergent Lignin (ADL), and Water-Soluble Carbohydrates (WSC) (Küchenmeister et al 2013;Brown et al 2017).…”