| In grazing systems, forage availability is a function of herbivore density, thus we hypothesized that the availability and quality of familiar foods influence diet mixing behavior. In pen trials, familiar foods were restricted to 10, 30, 50, and 70% of ad libitum while 3 novel toxin-containing foods were offered ad libitum. In these trials, as the availability of familiar foods decreased, total use of the toxin-containing foods increased, and conditioned lambs ate between 38%--49% of the toxin-containing foods despite ad libitum access to alternatives. We also conducted a field trial to examine the influence of stock density on diet mixing. There were 3 treatments: high and low density---moved daily---and temporal allocation---3X the area of high density and moved every 3 days. Sagebrush consumption was: high density > temporal allocation > low density. Collectively, these results suggest that the availability of nutritious alternatives influenced diet mixing patterns. |
