Influence of Forage Diversity and Condensed Tannins on Livestock Foraging Behavior, Production and Environmental Impact

Eating a combination of forages with different chemistries (i.e., nutrients, beneficial compounds such as tannins) may enhance ruminant nutrition and reduce environmental impacts relative to eating single forages. I explored the influence of offering sheep and cattle all possible combinations of tanniferous (i.e., plants with tannins; birdsfoot trefoil, sainfoin) and non-tanniferous legumes (i.e., plants without tannins; alfalfa) or their monocultures on animal performance, behavior, and methane and nitrogen (N) emissions. Offering choices among these legumes to penned sheep improved intake and diet digestibility relative to feeding monocultures. Mixtures selected by sheep were better digested than mixtures containing equal parts of the forages (indifferent selection), and similar to the legume of greatest digestion rate (alfalfa). In both sheep and cattle, tanniferous forages shifted the site of N excretion from urine to feces, which reduces environmental impacts, as fecal N is in the form of organic N and is metabolized at a slower rate than N in urine. Heifers grazing choices between tanniferous legumes showed the greatest decline in urinary N concentration, suggesting compounded effects that enhance N economy in grazing ruminants and reduce urinary N excretion to the environment. Enteric methane emissions were not affected by treatment, but heifers offered choices among all three legumes showed the greatest body weight gains, implying reductions in the number of days to slaughter, which reduces methane emissions during the finishing process. Grazing behavior and stress levels in heifers offered choices among strips of the three legumes were similar to animals grazing monocultures. Thus, my results suggest that grazing forage combinations increased animal productivity and reduced environmental impacts without affecting behavior or stress levels relative to grazing single forages, all benefits that lead to more sustainable pasture-based finishing systems

Influence of Forage Diversity and Condensed Tannins on Livestock Foraging Behavior, Production and Environmental Impact

Tesis para obtener el grado de Doctor of Philosophy (PhD), de la Utah State University, en agosto de 2020Eating a combination of forages with different chemistries (i.e., nutrients, beneficial compounds such as tannins) may enhance ruminant nutrition and reduce environmental impacts relative to eating single forages. I explored the influence of offering sheep and cattle all possible combinations of tanniferous (i.e., plants with tannins; birdsfoot trefoil, sainfoin) and non-tanniferous legumes (i.e., plants without tannins; alfalfa) or their monocultures on animal performance, behavior, and methane and nitrogen (N) emissions. Offering choices among these legumes to penned sheep improved intake and diet digestibility relative to feeding monocultures. Mixtures selected by sheep were better digested than mixtures containing equal parts of the forages (indifferent selection), and similar to the legume of greatest digestion rate (alfalfa). In both sheep and cattle, tanniferous forages shifted the site of N excretion from urine to feces, which reduces environmental impacts, as fecal N is in the form of organic N and is metabolized at a slower rate than N in urine. Heifers grazing choices between tanniferous legumes showed the greatest decline in urinary N concentration, suggesting compounded effects that enhance N economy in grazing ruminants and reduce urinary N excretion to the environment. Enteric methane emissions were not affected by treatment, but heifers offered choices among all three legumes showed the greatest body weight gains, implying reductions in the number of days to slaughter, which reduces methane emissions during the finishing process. Grazing behavior and stress levels in heifers offered choices among strips of the three legumes were similar to animals grazing monocultures. Thus, my results suggest that grazing forage combinations increased animal productivity and reduced environmental impacts without affecting behavior or stress levels relative to grazing single forages, all benefits that lead to more sustainable pasture-based finishing systems.EEA BordenaveFil: Lagrange, Sebastian Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; Argentina

Tannin-Containing Legumes and Forage Diversity Influence Foraging Behavior, Diet Digestibility, and Nitrogen Excretion by Lambs

Diverse combinations of forages with different nutrient profiles and plant secondary compounds may improve intake and nutrient utilization by ruminants. We tested the influence of diverse dietary combinations of tannin- (sainfoin-Onobrichis viciifolia; birdsfoot trefoil-Lotus corniculatus) and non-tannin- (alfalfa-Medicago sativa L.) containing legumes on intake and diet digestibility in lambs. Freshly cut birdsfoot trefoil, alfalfa, and sainfoin were offered in ad libitum amounts to 42 lambs in individual pens assigned to 7 treatments (6 animals/treatment): 1) single forage species (sainfoin [SF], birdsfoot trefoil [BFT], and alfalfa [ALF]), 2) all possible 2-way choices of the 3 forage species (alfalfa-sainfoin [ALF-SF], alfalfa-birdsfoot trefoil [ALF-BFT], and sainfoin-birdsfoot trefoil [SF-BFT]), or 3) a choice of all 3 forages (alfalfa-sainfoin-birdsfoot trefoil [ALF-SF-BFT]). Dry matter intake (DMI) was greater in ALF than in BFT (P = 0.002), and DMI in SF tended to be greater than in BFT (P = 0.053). However, when alfalfa was offered in a choice with either of the tannin-containing legumes (ALF-SF; ALF-BFT), DMI did not differ from ALF, whereas DMI in SF-BFT did not differ from SF (P \u3e 0.10). When lambs were allowed to choose between 2 or 3 legume species, DMI was greater (36.6 vs. 33.2 g/kg BW; P = 0.038) or tended to be greater (37.4 vs. 33.2 g/kg BW; P = 0.067) than when lambs were fed single species, respectively. Intake did not differ between 2- or 3-way choice treatments (P = 0.723). Lambs preferred alfalfa over the tannin-containing legumes in a 70:30 ratio for 2-way choices, and alfalfa \u3e sainfoin \u3e birdsfoot trefoil in a 53:33:14 ratio for the 3-way choice. In vivo digestibility (DMD) was SF \u3e BFT (72.0% vs. 67.7%; P = 0.012) and DMD in BFT tended to be greater than in ALF (64.6%; P = 0.061). Nevertheless, when alfalfa was offered in a choice with either sainfoin or birdsfoot trefoil (ALF-SF; ALF-BFT), DMD was greater than ALF (P \u3c 0.001 and P = 0.007, respectively), suggesting positive associative effects. The SF treatment had lower blood urea nitrogen and greater fecal N/N intake ratios than the ALF, BFT, or ALF-BFT treatments (P \u3c 0.05), implying a shift in the site of N excretion from urine to feces. In conclusion, offering diverse combinations of legumes to sheep enhanced intake and diet digestibility relative to feeding single species, while allowing for the incorporation of beneficial bioactive compounds like condensed tannins into the diet

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

Multi-object spectroscopy of stars in the CoRoT fields I: Early-type stars in the CoRoT-fields IRa01, LRa01, LRa02

Observations of giant stars indicate that the frequency of giant planets is much higher for intermediate-mass stars than for solar-like stars. Up to now all known planets of giant stars orbit at relatively far distances from their host stars. It is not known whether intermediate-mass stars also had many close-in planets when they were on the main sequence, which were then engulfed when the star became a giant star. To understand the formation and evolution of planets it is therefore important to find out whether main-sequence stars of intermediate-mass have close-in planets or not. A survey for transiting planets of intermediate-mass stars would be ideal to solve this question, because the detection of transiting planets is not affected by the rapid rotation of these stars. As a first step for an efficient survey we need to identify intermediate-mass stars in the CoRoT-fields, which can then be used as an input list. To compile the input list we derived the spectral types of essentially all O, B and A stars down to 14.5 mag in the CoRoT fields IRa01, LRa01, LRa02 taken with the multi-object spectrograph AAOmega. We determined the spectral types by comparing the spectra with template spectra from a library. In total we identify 1856 A and B stars that have been observed with CoRoT. Given the number of planets that have been detected in these fields amongst late-type stars, we estimate that there are one to four transiting planets of intermediate-mass stars waiting to be discovered. Our survey not only allows us to carry out a dedicated planet search programme but is also essential for any types of studies of the light curves of early-type stars in the CoRoT database. We also show that it would be possible to extend the survey to all fields that CoRoT has observed using photometrically determined spectral types.Comment: 57 pages, 12 figures, accepted for publication in Astronomy and Astrophysic

Formation and Evolution of Planetary Systems (FEPS): Properties of Debris Dust around Solar-type Stars

We present Spitzer photometric (IRAC and MIPS) and spectroscopic (IRS low resolution) observations for 314 stars in the Formation and Evolution of Planetary Systems (FEPS) Legacy program. These data are used to investigate the properties and evolution of circumstellar dust around solar-type stars spanning ages from approximately 3 Myr to 3 Gyr. We identify 46 sources that exhibit excess infrared emission above the stellar photosphere at 24um, and 21 sources with excesses at 70um. Five sources with an infrared excess have characteristics of optically thick primordial disks, while the remaining sources have properties akin to debris systems. The fraction of systems exhibiting a 24um excess greater than 10.2% above the photosphere is 15% for ages < 300 Myr and declines to 2.7% for older ages. The upper envelope to the 70um fractional luminosity appears to decline over a similar age range. The characteristic temperature of the debris inferred from the IRS spectra range between 60 and 180 K, with evidence for the presence of cooler dust to account for the strength of the 70um excess emission. No strong correlation is found between dust temperature and stellar age. Comparison of the observational data with disk models containing a power-law distribution of silicate grains suggest that the typical inner disk radius is > 10 AU. Although the interpretation is not unique, the lack of excess emission shortwards of 16um and the relatively flat distribution of the 24um excess for ages <300~Myr is consistent with steady-state collisional models.Comment: 85 pages, 18 figures, 4 tables; accepted for publication in ApJ

University of Nebraska Five-Year Strategy, Revised August 12, 2020

The University of Nebraska Five-Year Strategy: Trust, Predictability, and Positive Outcomes for Nebraskans In February 2020, the newly named president of the University of Nebraska system, Ted Carter, gathered a diverse 28-member team of students, faculty, staff, and administrators to help chart the path forward for Nebraska’s public university. The team’s goal: At a time of great change in higher education, lay out a vision for what the future should look like for the University of Nebraska. Broad themes quickly emerged, including student access and success, excellence in teaching and research, diversity and inclusion, partnerships, and fiscal effectiveness. Then COVID-19 hit, forcing a pause in the team’s work. The ensuing months showed that the initial priorities identified by the team were not only still relevant, but more important than ever in defining the future of higher education. From that early work has emerged a five-year strategy for growth and success across the four-campus University of Nebraska system. In addition to the strategic planning team, Carter engaged alumni and donors, elected leaders, leaders in business and agriculture, the Board of Regents, NU senior leadership, and others in conversations about the University’s future. The resulting strategy is built around several key principles: The value of higher education is clear and growing. Nebraska’s success is tied to that of its University. Students come first. The University of Nebraska should be the best place in the country to be a student, providing high-quality, affordable, accessible education that prioritizes students’ mental and physical health and prepares them for post-graduation success. Our people are our greatest asset. We will invest accordingly. We have a responsibility to make the best use of every dollar Nebraskans entrust to us. Themes of equity and inclusion touch everything we do. We will be a University for everyone—successful only when all voices are heard. Finally, Nebraskans should know what to expect from their University. We must work every day to maintain the trust and confidence of the people of our state

Sustentabilidad socio-económica de explotaciones agropecuarias del sur de la provincia de Buenos Aires. Resultados preliminares de la prueba de indicadores

Posiblemente uno de los factores que más conspiró contra los numerosos intentos de atenuar el impacto ambiental de la actividad agropecuaria haya sido la falta de consideración de aquellos aspectos sociales y económicos relacionados con sus usuarios. Por caso se intentaba detener la erosión del suelo, sin atender las limitaciones y condicionantes de quienes obtenían su sustento a partir del recurso. El concepto de sustentabilidad se desarrolló a partir del reconocimiento de muchos de esos aspectos incluyendo, actualmente, componentes que exceden lo ambiental o ecológico para considerar lo económico, las relaciones entre los individuos, y entre estos y el ambiente. La evaluación de la sustentabilidad de la actividad agropecuaria debe, necesariamente, incluir estos componentes para detectar en forma integral sus fortalezas y debilidades. El uso de indicadores, que reflejen el estado de cada componente de la sustentabilidad, en relación con valores tolerables o críticos, permite aportar a estos objetivos. Sin embargo para lograr la apropiada valoración de la sustentabilidad es necesario garantizar primero la adecuación, pertinencia, coherencia y sensibilidad de los indicadores construidos (Cáceres, 2007). En un trabajo anterior (Krüger et al. 2007), se seleccionaron indicadores de sustentabilidad aplicables a explotaciones agropecuarias del sur de la provincia de Buenos Aires, y se describió la metodología de trabajo interdisciplinario utilizada para identificarlos. Más recientemente se analizó la aplicación del componente ambiental de estos indicadores sobre una muestra de explotaciones seleccionadas al efecto (Krüger et al. 2009). La presente ponencia tiene como objetivo analizar los resultados de la aplicación de indicadores correspondientes al componente socio-económico sobre dichas explotaciones, completando así la prueba del esquema, y un diagnóstico preliminar de la sustentabilidad de las explotaciones de la región.EEA BordenaveFil: Kruger, Hugo Ricardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; ArgentinaFil: Agamennoni, Raúl José. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi; ArgentinaFil: Couderc, Jorge Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave. Agencia de Extensión Rural Pigüé; ArgentinaFil: Fernandez Mayer, Anibal. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave. Agencia de Extensión Rural Coronel Pringles; ArgentinaFil: González Ferrín, María Soledad. Instituto Nacional de Tecnología Agropecuaria (INTA). Chacra Experimental Integrada Barrow; ArgentinaFil: Lagrange, Sebastian Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; ArgentinaFil: López, Ricardo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; ArgentinaFil: Pelta, Hector Raul. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; ArgentinaFil: Presa, Cecilia Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; ArgentinaFil: Venanzi, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave. Agencia de Extensión Rural Pigüé; ArgentinaFil: Vigna, Mario Raúl. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bordenave; Argentin

The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b

We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is a $<$20 M$_\mathrm{Jup}$ widely separated ($\sim$8\arcsec, a = 150 au), young, planetary-mass companion that shares photometric colors and spectroscopic features with the directly imaged exoplanets HR 8799 c, d, and e. As an L-to-T transition object, VHS 1256 b exists along the region of the color-magnitude diagram where substellar atmospheres transition from cloudy to clear. We observed VHS 1256~b with \textit{JWST}'s NIRSpec IFU and MIRI MRS modes for coverage from 1 $\mu$m to 20 $\mu$m at resolutions of $\sim$1,000 - 3,700. Water, methane, carbon monoxide, carbon dioxide, sodium, and potassium are observed in several portions of the \textit{JWST} spectrum based on comparisons from template brown dwarf spectra, molecular opacities, and atmospheric models. The spectral shape of VHS 1256 b is influenced by disequilibrium chemistry and clouds. We directly detect silicate clouds, the first such detection reported for a planetary-mass companion.Comment: Accepted ApJL Iterations of spectra reduced by the ERS team are hosted at this link: https://github.com/bemiles/JWST_VHS1256b_Reduction/tree/main/reduced_spectr

The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems IV: NIRISS Aperture Masking Interferometry Performance and Lessons Learned

We present a performance analysis for the aperture masking interferometry (AMI) mode on board the James Webb Space Telescope Near Infrared Imager and Slitless Spectrograph (JWST/NIRISS). Thanks to self-calibrating observables, AMI accesses inner working angles down to and even within the classical diffraction limit. The scientific potential of this mode has recently been demonstrated by the Early Release Science (ERS) 1386 program with a deep search for close-in companions in the HIP 65426 exoplanetary system. As part of ERS 1386, we use the same dataset to explore the random, static, and calibration errors of NIRISS AMI observables. We compare the observed noise properties and achievable contrast to theoretical predictions. We explore possible sources of calibration errors, and show that differences in charge migration between the observations of HIP 65426 and point-spread function calibration stars can account for the achieved contrast curves. Lastly, we use self-calibration tests to demonstrate that with adequate calibration, NIRISS AMI can reach contrast levels of $\sim9-10$ mag. These tests lead us to observation planning recommendations and strongly motivate future studies aimed at producing sophisticated calibration strategies taking these systematic effects into account. This will unlock the unprecedented capabilities of JWST/NIRISS AMI, with sensitivity to significantly colder, lower mass exoplanets than ground-based setups at orbital separations inaccessible to JWST coronagraphy.Comment: 20 pages, 12 figures, submitted to AAS Journal