IN VITRO DIGESTIBILITY OF RANGE FORAGE PLANTS OF THE FESTUCA SCABRELLA ASSOCIATION

The in vitro digestibility of cellulose was determined for 20 grasses, 6 f orbs, and 6 miscellaneous browse species of the Festuca scabrella association of southwestern Alberta. From this was calculated the "Nutritive Value Index" (N.V.I.) and percentage of digestible protein. The mean N.V.I. and the mean digestible protein of the four cultivated grasses, Bromus inermis, Elymus junceus, Festuca rubra, and Phleum pratense, at each stage of growth, was higher than the respective mean of the native species of grasses. However, Bromus pumpellianus, a native species, had a higher mean N.V.I. for all stages of growth than any of the other grasses studied. The forbs as a class were equal or superior to the grasses in N.V.I. and percentage of digestible protein. It is suggested that other factors such as palatability, toxicity, and regional adaptation should be considered before a species is adequately evaluated as a range forage.