Elk are ruminants, like cattle and sheep, and therefore can make use of fibrous feeds because of the microbes that aid digestion in their rumen. However, ruminants vary in their selection and use of fibrous feeds. Fallow and whitetail deer are very selective eaters, choosing to consume only the most succulent and digestible plants and plant parts. Red deer and elk will eat and digest feeds higher in fiber content, but will leave plant parts that bison, sheep and cattle will readily consume.

All deer are highly seasonal in their eating habits. Voluntary intake decreases by as much as 40 – 60% during the winter, as compared to spring and summer peaks. This is a considerable advantage in temperate climates, where low-cost pasture growth peaks at the same time as the feed intake of farmed deer and elk.