While-tailed Deer Food Habits and Nutritional Status as Affected by Grazing and Deer-Harvest Management

White-tailed deer were collected in 1979 and 1980 from two areas in central Texas to determine differences in diets and nutritional status between years, sexes, and areas. Area 1 was more heavily populated with white-tailed deer, exotic big game, and domestic livestock than Area 2. Differences in summer and fall precipitation levels between years were reflected in altered forb and browse consumption by deer as determined from rumen contents. Differences in forb selection, oak mast consumption, and juniper browse consumption were detected between areas and were considered evidence of differences in range condition between areas. White-tails obtained from Area 1 were older than those from Area 2, but were not significantly larger in carcass weights, which also reflected the lower range condition of Area 1. Crude protein levels of rumen contents were greater in females than males and were greater in deer obtained from Area 1 than Area 2. These differences in rumen protein resulted from differences in consumption of acorns, a highly preferred, but low protein food item. Kidney fat indices reflected differences in rainfall patterns between years. Native and exotic big game populations and livestock grazing must be controlled to maintain a high level of nutritional status in the economically important white-tailed deer of central Texas.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Estimation of Fecal Output and Particulate Passage Rate with a Pulse Dose of Ytterbium-Labeled Forage

Twelve rumen-cannulated lambs (avg. wt. 40 kg), fed long-stem alfalfa or prairie hay in a crossover design (two, 15-day periods) were used to compare estimates of fecal output from a pulse dose of ytterbium (Yb)-labeled forage and fecal collection bags. Estimates of fecal output (g/day) with Yb-labeled forages were not different (P>.05) from total collection values for lambs fed either alfalfa or prairie hay. Fecal output from a pulse dose of Yb was 100 +/- 2% of total collection for lambs fed alfalfa and 103 +/- 3% for lambs fed prairie hay. Particulate passage from the rumen was faster (P<.01) in lambs fed alfalfa (7.0%/hr) then in lambs fed prairie hay (3.9%/hr). A pulse dose of Yb-labeled hay appears to prove reliable estimates of fecal output as well as passage rate estimates, but validation of techniques in free-grazing ruminants is needed.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Quantitative simulation of wave propagation in a human leg to support the ultrasonic noninvasive assessment of human bones

This paper presents a dedicated Finite Element approach for quantitative time-transient simulations of stress and pressure waves propagation in biological structures as human bones. The tool, starting from a magnetic resonance image (MRI) as the one of a human leg, builds a three-dimensional finite element (FE) mesh by converting voxels into elements. This step does not require any segmentation or further geometric interpretation of the tissue structure, only the mechanical properties have to be provided via Hounsfield (HU) number density mapping. The proposed tool improves upon the usually adopted models taking into account the irregular geometry of the bone as well as the soft tissues and their damping role, typically neglected. The tool code can handle models of hundred millions of elements in a standard PC desktop, exceeding thus capabilities of commercially available FEM codes. Here, an application on a human leg is proposed to show the potential of the proposed tool. The results of the time-transient simulations are next exploited to validate the use of guided waves models for the non invasive ultrasonic diagnosis of elongated bones. In particular, the recorded time-waveforms are analyzed via the 2D Fast Fourier Transform and the frequency-wavenumber energy content of the propagating waves is extracted. Such information is compared with the guided waves dispersion curves predicted, considering a representative cross-section of the tibia, via a Semi Analytical Finite Element (SAFE) formulation. Some final considerations on the comparison of the extracted and predicted dispersion curves close the paper

Cattle Grazing Blue Grama Rangeland. I. Seasonal Diets and Rumen Fermentation

Four field trials were conducted from early August to late October, 1982, on blue grama (Bouteloua gracilis) rangeland in south-central New Mexico to examine relationships among grazing season, diet botanical and chemical composition, and rumen fermentation in beef steers (Bos taurus). Diets contained an average of 83% grasses and 17% forbs from early August through late September and 77% forbs in late October. Cell wall content of the diet decreased from the early growing season (74.9%) through the onset of dormancy (64.9%) while acid detergent fiber and lignin increased (41.9 to 52.9% and 5.2 to 12.7%, respectively) and crude protein content declined from 18.4 to 11.7%. Soluble and insoluble nitrogen (N) fractions of the diet reflected crude protein; from 13 to 36% of N was in unavailable forms. The extent of in vitro organic matter digestion declined from the early growing season (66.5%) through onset of dormancy (47.9%). Ruminal ammonia concentrations declined as season progressed: 6.0 mg/100ml was the lowest concentration observed. Declining diet quality was accompanied by an upward shift in digesta pH and altered proportions of volatile fatty acids (VFA) in rumen contents. Total VFA concentration was highest in late August (106.3 mmoles/liter). Ruminal measures generally reflected changes in dietary protein and digestibility but concentrations could also reflect changes in digesta flow rates. Finally, data suggest that crude protein may not be a good measure of protein supply to livestock grazing on ranges with diverse forage types.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202