In Utah, most agricultural receipts are from livestock grazing pastures and rangelands. Using intensively managed irrigated pastures can increase profitability of beef production by $21 to $30 million compared with extensive rangeland grazing. Pasture-based production may also reduce costs for dairy producers in Utah by $12.5 million. Thus, sustaining and improving grazing practices is important. Unfortunately, monocultures or simple grass-legume mixtures used by many producers are not always ideal for intensively managed pastures. Mixtures of plants may provide benefits over monocultures because they can 1) extend the grazing season, 2) improve capture of soil nutrients and moisture, 3) reduce susceptibility to pests and disease, and 4) improve intake by providing grazing animals a choice of foods. Forcing animals to eat monocultures or simple mixtures may limit intake because all plants contain toxins and these toxins often limit intake. Variety allows animals to prevent over-ingesting a single toxin. Eating mixtures of toxins may actually lessen their negative effects and provide medicinal benefits to livestock.

In the summer of 2006, graduate student, Tiffany Lyman, conducted a study to examine how toxins in pasture grasses might complement each other. She focused on two alkaloids typically found in endophyte infected grasses such as tall fescue and reed canarygrass. Tannin and saponin were mixed with ground diets and fed to to lambs in pens to determine if eating these toxins would allow them to eat more food with alkaloids. Lambs fed tannins ate more of the diet with alkaloids. Lambs fed saponins ate more of the diet containing the alkaloid ergotamine. Planting pastures with complementary toxins may increase animal productivity on pasture.

Lyman's findings support research conducted at Utah State by Dr. Randy Weidmeier. In that study, calves grazing a pasture containing four plant species had better feed to gain ratios and higher average daily gains than calves grazing a pasture with a single plant species.

A second study planned for summer 2007 is a pasture study with cattle. The objective is to determine if cattle ingesting a diet of high-alkaloid varieties of grass (reed canarygrass or tall fescue) use high-tannin varieties of birdsfoot trefoil and high-saponin varieties of alfalfa to a greater extent than cattle grazing on low-alkaloid varieties of grass. An increased preference for forages and feeds high in tannins and saponins when ingesting alkaloids will support the idea that animals neutralize the negative effects of alkaloids by ingesting tannins and saponins.

The research will be conducted at Utah State University. Fred Provenza, Professor, and Juan Villalba, Research Assistant Professor, both of the Department of Wildland Resources will oversee the project.