The Interaction of Management with Botanical Composition of Irrigated Grass-Legume Pasture Mixtures in the Intermountain West USA

Beef produced on semi-arid range and milk produced in confinement are the main agricultural commodities in the semi-arid western USA. The studies reported here were undertaken to determine the suitability of irrigated pasture as an alternative to traditional beef and dairy production systems. The clipping and grazing studies were not run concurrently or within the same field, but were successive steps in selecting mixtures best-suited for rotational stocking of irrigated pastures in the Intermountain West. Summaries of productivity data have been reported elsewhere (MacAdam, 2002; MacAdam et al., 2004)

The Use of Temperate Tannin Containing Forage Legumes to Improve Sustainability in Forage–Livestock Production

Greenhouse gas emissions from ruminant livestock production systems contribute significantly to the environmental footprint of agriculture. Emissions are lower for feedlot systems than for grass-based systems primarily because of the extra time required for grass-finished cattle to reach slaughter weight. In contrast, legume forages are of greater quality than grasses, which enhances intake and food conversion efficiencies, leading to improvements in production and reductions in environmental impacts compared with forage grasses. In addition, the presence of certain bioactives in legumes such as condensed tannins (CT) enhance the efficiency of energy and protein use in ruminants relative to grasses and other feeds and forages. Grazing tannin-containing legumes also reduce the incidence of bloat and improve meat quality. Synergies among nutrients and bioactives when animals graze diverse legume pastures have the potential to enhance these benefits. Thus, a diversity of legumes in feeding systems may lead to more economically, environmentally, and socially sustainable beef production than grass monocultures or feedlot rations.EEA BordenaveFil: Lagrange, Sebastian Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; Argentina.Fil: MacAdam, Jennifer W. Utah State University. College of Agriculture and Applied Sciences; Estados Unidos.Fil: Villalba, Juan J. Utah State University. Quinney College of Natural Resources. Department of Wildland Resources; Estados Unidos

Integrating Plant Secondary Metabolites and Foraging Behavior to Enhance Animal Health in Ruminant Production Systems

Legumes and forbs contain bioactives or plant secondary compounds (PSC) with potential to enhance animal health through their antibiotic, antioxidant and immunomodulatory properties that are evident even at small dietary concentrations. In turn, ruminants can regulate their ingestion of PSC through behavioral mechanisms that allow for the efficient achievement of homeostasis. High concentrations of PSC lead to food avoidance, whereas lower content of PSC in the diet achieved through regulatory mechanisms of ingestion could promote medicinal and/or prophylactic effects in the animal and concomitant health benefits to milk and meat products. Under this context, we discuss the restructuring of rangelands and pasturelands through the strategic distribution of legume- and forb-rich patches in monotonous landscapes dominated by grasses, thus re-establishing their functionality. Such strategies can synergistically complement and provide new dimensions (prophylactic-medicinal, product quality) to the forage resources already available to livestock

Rocky Mountain Trefoil Beef

This fact sheet describes Rocky Mountain trefoil beef and how researchers at USU are exploring the use of tannin-containing legumes as a method fr finishing cattle to address environmental and efficiency concerns associated with the most common current beef production systems

Pasture Chemoscapes and Their Ecological Services

Ruminant livestock-production systems are between a rock and a hard place; they are experiencing increasing societal pressure to reduce environmental impacts in a world that demands increased food supply. Recent improvements in the understanding of the nutritional ecology of livestock by scientists may help livestock producers respond to these seemingly contradictory demands. Forages are nutrition and pharmacy centers with primary (nutrients) and plant secondary compounds (PSC; pharmaceuticals, nutraceuticals), which can provide multiple services for the proper functioning of agroecosystems. Legumes with lower contents of fiber and higher contents of nonstructural carbohydrates, coupled with different types and concentrations of PSC (e.g., condensed tannins, terpenes), create a diverse array of chemicals in the landscape (i.e., the “chemoscape”) with the potential to enhance livestock nutrition, health and welfare relative to foodscapes dominated by grasses and other conventional feeds. These PSC-containing plants may reduce methane emissions and nitrogen (N) excretion from animals while increasing animal growth rate compared with swards dominated by grasses, and provide meat quality that appeals to consumers. Condensed tannins from sainfoin and saponins from alfalfa and manure of cattle consuming these forages also reduce N mobilization in soils, reduce nutrient leaching, and increase plant-available N stores for future use. The challenge for future pastoral production systems is to design multifunctional spatiotemporal arrangements of forages with “ideal” chemical diversity for specific ecoregions, aiming to achieve sustainability while increasing production goals and improving ecosystem services. Thus, the objective of this review is to stimulate the quest for chemically and taxonomically diverse pastoral feeding systems that optimize overall productivity; reduce environmental impacts; and enhance livestock, soil, and human health

In Vitro Digestibility of Mountain-Grown Irrigated Perennial Legume, Grass and Forb Forages is Influenced by Elevated Non-Fibrous Carbohydrates and Plant Secondary Compounds

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

Theoretical He I Emissivities in the Case B Approximation

We calculate the He I case B recombination cascade spectrum using improved radiative and collisional data. We present new emissivities over a range of electron temperatures and densities. The differences between our results and the current standard are large enough to have a significant effect not only on the interpretation of observed spectra of a wide variety of objects but also on determinations of the primordial helium abundance.Comment: Accepted to ApJ

Crosswind Sensitivity of Passenger Cars and the Influence of Chassis and Aerodynamic Properties on Driver Preferences

Results of vehicle crosswind research involving both full-scale driver-vehicle tests and associated analyses are presented. The paper focuses on experimental crosswind testing of several different vehicle configurations and a group of seven drivers. A test procedure, which utilized wind-generating fans arranged in alternating directions to provide a crosswind "gauntlet", is introduced and described. Driver preferences for certain basic chassis and aerodynamic properties are demonstrated and linked to elementary system responses measured during the crosswind gauntlet tests. Based on these experimental findings and confirming analytical results, a two-stage vehicle design process is then recommended for predicting and analyzing the crosswind sensitivity of a particular vehicle or new design.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65022/1/MacAdam 1990 VSD Aerodynamic Crosswind paper.pd

Increased Nitrogen Retention and Reduced Methane Emissions of Beef Cattle Grazing Legume vs. Grass Irrigated Pastures in the Mountain West USA

Grazing studies were carried out over a 5-year period using pregnant cows, yearling calves and 2-year-old heifers to investigate the influence of diet on intake, methane (CH4) emissions and retention of nitrogen (N). Monoculture legume (birdsfoot trefoil, BFT and cicer milkvetch, CMV) or grass (meadow bromegrass, MBG) pastures were rotationally stocked, and during year 4 and year 5, treatments were contrasted with total mixed rations (TMR) fed in confinement. The sulfur hexafluoride (SF6) method was used to continuously measure enteric CH4 emissions. Intake was greater on legume pastures and on TMR than on grass pastures, and enteric CH4 emissions per unit of intake were lower on legumes compared with grass pastures. Legume pastures had elevated non-fiber carbohydrate (NFC) concentrations (400 g kg−1 dry matter; DM) typical of perennial legumes cultivated in the Mountain West. A N balance calculated in 2017–2018 demonstrated that N retention was greater for TMR and legume than grass pastures. Enteric CH4 emissions of grazing cow herds account for the majority of greenhouse gas (GHG) emissions from beef production and can be significantly reduced by using highly digestible forage legumes. The N retention of legumes can potentially enhance the efficiency of N use, thereby increasing the sustainability of grasslands.EEA BordenaveFil: MacAdam, Jennifer W. Utah State University. College of Agriculture and Applied Sciences. Department of Plants, Soils and Climate; Estados Unidos.Fil: Pitcher, Lance R. Amalgamated Sugar Company; Estados UnidosFil: Bolletta, Andrea Ivana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; Argentina.Fil: Guevara Ballesteros, Raúl David. Universidad Autónoma de Barcelona. Animal Welfare Education Centre; EspañaFil: Beauchemin, Karen A. Agriculture and Agri-Food Canada. Lethbridge Research and Development Centre; CanadáFil: Xin, Dai. Utah State University. Utah Agricultural Experiment Station; Estados Unidos.Fil: Villalba, Juan J. Utah State University. Quinney College of Natural Resources. Department of Wildland Resources; Estados Unidos