Browsing Journal of Range Management, Volume 38, Number 5 (September 1985) by Issue Date
Now showing items 21-24 of 24
Estimation of Fecal Output and Particulate Passage Rate with a Pulse Dose of Ytterbium-Labeled ForageTwelve 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.
A Precision Planter for Seedling Emergence EvaluationA modified version of the laboratory vacuum plate seed counter was developed for precision planting of small seeds in soil. The planter, a vacuum chamber constructed from rigid plastic plate, would palce 100 seeds on a 228 × 228 mm plot. The individual seed holders were hypodermic needles inserted into the bottom of the chamber on a square grid at a 25 mm spacing. When a vacuum was applied to the chamber, a single seed was held at the tip of each needle. Seedbed preparation consisted of forming small impressions in the soil surface with a grid spacing identical to the planter. With the planter properly aligned, a single seed was dropped into each impression. This technique was successfully used with seeds ranging in size and shape of Panicum antidotale Retz to Eragrostis lehmanniana Nees. Three people were able to seed 120 plots with 100 seeds in less than 4 hours.
Western Wheatgrass Responses to Simulated GrazingTo evaluate responses of range grasses to herbage removal, removal patterns should simulate those under grazing. We compared responses of western wheatgrass (Agropyron smithii Rydb.) in mixed-grass range to no clipping, conventional clipping, and clipping which simulated continuous grazing. Two years of simulated grazing did not affect herbage production or tiller numbers, but both declined under conventional clipping. Belowground phytomass decreased as herbage removal increased. Total nonstructural carbohydrate concentration in rhizomes decreased when utilization exceeded about 40%, but that of roots and crowns decreased only when utilization exceeded 60-70%.
Values of Four Communities for Mule Deer on Ranges with Limited Summer HabitatFour plant communities were evaluated from May through September for mule deer dietary and nutritional values. The communities were dominated by Utah serviceberry, Gambel oak, big sagebrush, and mixed browse. In early summer deer diets contained many browse and forb species and were high in crude protein, but as summer progressed fewer species were selected and dietary crude protein declined, especially in the big sagebrush and serviceberry communities. Thus late summer was determined the critical period for forage quality. Range conditions were reflected by body size and condition of deer in fall.