Browsing Journal of Range Management, Volume 54, Number 4 (July 2001) by Subjects
Now showing items 1-3 of 3
A proposed method for determining shrub utilization using (LA/LS) imageryUtilization of plant above ground biomass has continued to be a critical yet difficult assessment in rangeland monitoring. Shrub size and woody structure further compound the measurement of shrub biomass utilization. This study was designed to determine the potential utility of low altitude/large scale (LA/LS) imagery in assessing shrub utilization. A near monoculture of Ceriotoides lanata (Pursh) J.T. Howell (winterfat) located in the western desert shrubland of Utah was used to evaluate this technique. Four, 3.1 by 3.1 m plots were identified and the shrubs within the plots were defoliated by hand-picking at about 10% intervals with imagery of the plots obtained between pickings. Imagery was obtained using a radio controlled airplane (drone) fitted with a 35 mm camera. Images were evaluated using image processing software and the resulting reflectance data correlated with defoliation percentages (weight basis) for each plot. Reflectance data from images correlated highly with defoliation percentages (r2 > 0.9). This technique of using LA/LS imagery shows promise for a quick and accurate tool in assessing utilization of shrubs.
Effects of proanthocyanidins on digestion of fiber in foragesThe ability of proanthocyanidins (PA) to form insoluble complexes with proteins and polysaccharides affects fiber digestion and analysis. This review discusses these effects in relationship to the application of the detergent system of forage analysis. A fraction of the PA in plants remains after extraction for analysis. Insoluble PA may be a natural part of the plant cell wall or may be insoluble because of high molecular weight and post harvest reactions. These reactions increase the amount of insoluble PA and decrease the amount of soluble PA. The butanol-HCl assay is the most suitable method for analysis of insoluble PA. Insoluble PA are associated with negative apparent digestion coefficients for acid-detergent lignin (ADL), neutral-detergent insoluble N and acid-detergent insoluble N. The addition of sodium sulfite to neutral detergent eliminates insoluble PA from NDF. However, the addition of sodium sulfite to neutral detergent will give misleading results in relationship to true digestibility of protein. The difference between fiber fractions that are prepared with and without the addition of sodium sulfite to neutral-detergent may estimate the amount of PA/protein complex associated with NDF. A better understanding of the relationship between PA structure and function is necessary to manipulate PA in forages through breeding or genetic engineering. The interaction between PA and fiber analysis and digestion is an important component of this research.
Statistical analyses of fluorometry data from chloroform filtrate of lamb fecesAccurately identifying the botanical composition of free-ranging animal diets remains a challenge. Currently accepted procedures are time consuming, many requiring painstaking sample preparation while none produce data useful for real-time management. Automated procedures focusing on detection of chemical and/or physical plant properties using specific molecules called fluorophores offers possibilities for determining the species composition of herbivore diets. This study was designed to evaluate fluorometry techniques in herbivore diet determinations using fecal samples obtained from 13 lambs fed a basal diet of tobosa hay (Pleuraphis mutica Buckley), and containing 4 different levels (0, 10, 20, and 30%) of tarbush (Flourensia cernua D C.) leaf material. Chloroform (CHCl3) filtrate obtained from the lamb's feces was exposed to UV light from a xenon arc lamp. This caused fluorophore molecules in the filtrate to have their outer shell electrons move to a higher energy state as a result of UV light excitation. After excitation by UV light at 310, 320, 330, 340, 350, and 355 nm, the fluorophores returned to their ground state giving off light (fluorescence). This fluorescence intensity (counts) varied and when captured using appropriate electronics, produced 1,024 pairs of light intensities (counts) and fluorescent wavelengths between 175 and 818 nm in 0.63 nm increments. Previous research indicated differences among diets could be determined using distinct peaks in the red and blue regions of the visible light spectrum and a univariate (1 variable at a time) analysis. This research demonstrates the entire fluorescence data set can be used to determine differences among diets using multivariate statistics. Sequences of 5 increasingly complex statistical techniques were used to distinguish among diets: 2-dimensional plots, polynomial regression models, confidence interval plots, discriminant analysis, and 3-dimensional plots. Two-dimensional plots indicated 2 spectral fluorescence peaks, 1 in the blue-green (420-600 nm) and 1 in the red (640-720 nm) region of the visible spectrum. Because of the asymmetrical nature of these peaks, fifth-order polynomials were developed to differentiate among the 4 diets. Statistical reliability was high when discriminating between diets containing no tarbush leaf and the diets containing 30% tarbush leaf; however, it was not possible to statistically separate diets containing intermediate (10 and 20%) amounts of tarbush leaf material from each other or from the 2 extremes (0 and 30% tarbush leaf). These results suggest spectral signatures arising from fluorometry data may be useful for differentiating among botanical composition diets that differ in plant form, but that a multivariate approach may require large sample sizes.