Nitrogen composition of herbage in relation to the ruminant animal

Herbage contributes much dietary protein to ruminant diets. High-producing ruminants need part of the dietary protein to be resistant to ruminal degradation. Estimates of herbage protein degradability have not considered agronomic factors in herbage production. This research examined how herbage species, maturity stage, plant part, and nitrogen (N) fertilization modify the N composition of herbage;Smooth bromegrass (Bromus inermis Leyss.), timothy (Phleum pratense L.), red clover (Trifolium pratense L.), and alfalfa (Medicago sativa L.) were harvested at four, two-week intervals during spring of 1984 and 1985. Total herbage, leaves, and stems were analysed for herbage quality and various N fractions. Less than 13% of the total N in herbage was available fiber N (AFN) (neutral detergent fiber N (NDFN) minus acid detergent fiber N (ADFN)). Available fiber N increased with herbage maturity. Legumes had twice the N in ADF as did grasses. Concentrations of NDFN and ADFN in leaves and stems reflected the different amounts and proportions of tissues in each organ. Stems had more ADFN, which reflects the greater amount of lignified structural tissue. Leaves had more NDFN, which mirrors the greater amount of mesophyll tissue. Immature herbage was most digestible, least in NDF, and highest in N concentration;Smooth bromegrass (SBG) was grown in mixture with alfalfa or fertilized with three levels of N in combination with three levels of nitrapyrin, a nitrification inhibitor, and harvested at four, two-week intervals during spring of 1985 and 1986. Total herbage of SBG was analyzed for various N fractions. Nitrapyrin had no effect on chemical composition of herbage. Nitrogen fertilizer increased both dry matter yield and N concentration in SBG, but did not alter available fiber N or herbage quality;It is concluded that herbage should be managed to optimize the yield of digestible energy to best use the large proportion of degradable N in herbage

Water Use Efficiency by Switchgrass Compared to a Native Grass or a Native Grass Alfalfa Mixture

Perennial grass systems are being evaluated as a bioenergy feedstock in the northern Great Plains. Inter-annual and inter-seasonal precipitation variation in this region will require efficient water use to maintain sufficient yield production to support a mature bioenergy industry. Objectives were to evaluate the impact of a May–June (early season) and a July–August (late season) drought on the water use efficiency (WUE), amount of water used, and biomass production in monocultures of switchgrass (Panicum virgatum L.), western wheatgrass (Pascopyrum smithii (Rydb.) Á. Löve), and a western wheatgrass–alfalfa (Medicago sativa L.) mixture using an automated rainout shelter. WUE was strongly driven by biomass accumulation and ranged from 5.6 to 7.4 g biomass mm−1 water for switchgrass to 1.06 to 2.07 g biomass mm−1 water used with western wheatgrass. Timing of water stress affected WUE more in western wheatgrass and the western wheatgrass–alfalfa mixture than switchgrass. Water deficit for the western wheatgrass–alfalfa mixture was 23 % lower than western wheatgrass (P=0.0045) and 31 % lower than switchgrass (P\u3c0.0001) under the May–June stress water treatment, while switchgrass had a 37 and 38%greater water deficit than did western wheatgrass or western wheatgrass–alfalfa mixture, respectively (P\u3c0.001) under the July–August water stress treatment. Water depletion was always greatest in the upper 30 cm. Switchgrass had greater WUE but resulted in greater soil water depletion at the end of the growing season compared to western wheatgrass and a western wheatgrass– alfalfa mixture which may be a concern under multi-year drought conditions

Productivity of 10 Warm-Season Perennial Grasses Over Several Years in Central Texas.

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Alternative Methods of Estimating Forage Height in Pastures can be Cross Calibrated

Describes how to cross calibrate alternative measurements of pasture forage mass

Well-managed grazing systems: A forgotten hero of conservation

Ecologically sound grazing management is an underused and underappreciated conservation tool in the eastern United States. We contend that significant policy and educational barriers stand in the way of expanding the use of this conservation tool. Well-managed pasture systems combine vigorous perennial vegetation cover, reduced pesticide and fertilizer inputs, and lower costs of production using ecological approaches to generate ecosystem services for society, as well as economic sustainability for the producer. The majority of currently available conservation policy tools were designed to address either rangeland grazing situations in the western United States or conservation cropping in the eastern United States. To promote well-managed pastures in the eastern United States, resource managers and government agencies struggle to adapt programs that are really designed for annual row crop systems. Additional educational and technical assistance resources are needed for promoting well-managed pasture-based farming in the region. This paper summarizes the potential of well-managed pasture systems to provide ecosystem services, provides thoughts for discussion on the barriers to adoption of such systems in the eastern United States, and offers some solutions to move such systems forward through policy and educational efforts. These ideas were first presented at a symposium as part of the 2011 Annual Conference of the Soil and Water Conservation Society in Washington, DC

Multimodal mechano-microscopy reveals mechanical phenotypes of breast cancer spheroids in three dimensions

Funding: This study was supported by the Australian Research Council, The Ian Potter Foundation, Department of Health, Western Australia (WANMA2021/1), Research Training Program Scholarship, Hackett Postgraduate Research Scholarship, and Cancer Council Western Australia (RP G0039). P.W. was supported by the 1851 Research Fellowship from the Royal Commission. B.F.K acknowledges funding from the NAWA Chair programme of the Polish National Agency for Academic Exchange and from the National Science Centre, Poland.Cancer cell invasion relies on an equilibrium between cell deformability and the biophysical constraints imposed by the extracellular matrix (ECM). However, there is little consensus on the nature of the local biomechanical alterations in cancer cell dissemination in the context of three-dimensional (3D) tumor microenvironments (TMEs). While the shortcomings of two-dimensional (2D) models in replicating in situ cell behavior are well known, 3D TME models remain underutilized because contemporary mechanical quantification tools are limited to surface measurements. Here, we overcome this major challenge by quantifying local mechanics of cancer cell spheroids in 3D TMEs. We achieve this using multimodal mechano-microscopy, integrating optical coherence microscopy-based elasticity imaging with confocal fluorescence microscopy. We observe that non-metastatic cancer spheroids show no invasion while showing increased peripheral cell elasticity in both stiff and soft environments. Metastatic cancer spheroids, however, show ECM-mediated softening in a stiff microenvironment and, in a soft environment, initiate cell invasion with peripheral softening associated with early metastatic dissemination. This exemplar of live-cell 3D mechanotyping supports that invasion increases cell deformability in a 3D context, illustrating the power of multimodal mechano-microscopy for quantitative mechanobiology in situ.Peer reviewe