DIET, NUTRITION, AND REPRODUCTIVE ... - NWIFC Access

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and forbs were taken from just above ground, shrubs were collected as leaves and twigs,
ferns were collected as 75% of frond, conifers were collected as new or young growth.
This collection method reflected observer bias, and may not accurately reflect elk
selection of particular plants or plant parts. Grazing animals are known to select forage
higher in quality than what is available (Van Dyne et al. 1980), whereas I collected plant
samples from random plants at a foraging location. All plant samples were air dried (18-
22 o C) for 2 to 5 days until brittle, and stored in paper bags.
A subset of the collected plant samples was selected for nutritional analysis. The
selection of the subset of plant samples was based on the diet results from fecal analysis.
Every forage plant species found in the diet could not be analyzed. Two criteria were
used to reduce the list of plant species to a feasible number of plants (6 to 7) for each
sampling period. First, I selected the three or four plant species that made up the greatest
percentage of the diet across all herds for each sampling period. Second, I selected three
or four plant species that made up the greatest percent of the diet for only a few herds for
each sampling period. Combining these two criteria I attempted to analyze the three
plant species that made up the greatest percentage of each herds’ diet for each sampling
period.
Each plant species was analyzed for crude protein, in-vitro dry matter digestibility
(hereafter digestibility), and gross available energy. All plants were ground to 1 mm
screen size in a Wiley Mill (Model 3383L20, Thomas Scientific, Swedesboro, NJ). The
Wildlife Nutrition Lab at Washington State University completed the dry-weight protein
(Kjeldahl method) and digestibility analysis (Tilley and Terry 1963). Laboratory analysis