by Elizabeth Picking, University of Missouri Extension

Seeing the bright green new growth pop up in our pastures signals the end of winter and the transition into spring. As the short green carpet starts to come up, cattle start chasing the short growth and may turn their noses up to hay they were previously eating well. However, allowing cattle to nip off this short regrowth can slow down the pasture growth moving into the spring. Research at the U.S. Dairy Forage Research Center in 2011 suggests that 500 pounds of forage growth per acre is lost when grass is grazed while still short in the spring.

How short should we graze pastures? The type of grass in your pasture will determine how short it should be grazed. When grazing most grasses like fescue, orchard grass, Bermuda, timothy and crabgrass, you should leave 3 inches (in.) or more so the plant has enough leaf material to regrow in a timely manner. Grazing below 3 in. leads to slower regrowth and potential for root loss under the soil. If grazed short repeatedly, producers can start to see thinning forage stands and more weed encroachment in those pastures.

Where I am in Missouri, most cattle producers are grazing fescue. In addition to plant health concerns, the ergovaline in fescue constricts blood vessels and causes symptoms like heat stress; poor average daily gains; and loss of tail switches, eartips or gangrene of feet. The ergovaline is concentrated in the bottom couple inches of the plant, so maintaining a grazing height of 3 inches or higher limits the ergovaline cattle consume and reduces some of those animal health concerns.

Many livestock producers have incorporated native warm-season grasses like big bluestem, little bluestem, Indiangrass and gamagrass into their grazing systems. Those species have a taller growing point and should have 12 in. or higher left behind to regrow.