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In an experimental pasture at the Grazinglands Research Laboratory near El Reno, Oklahoma, ecologist Brian Northup collects samples to describe availability and quality of forage. Click the image for more information about it.

Targeting the Southern Plains "Forage Gap"

By Luis Pons
December 2, 2005

Perennial cool-season grasses can help livestock producers in the southern Great Plains get through seasonal “forage gaps” when typical grasses that grazing animals depend upon don’t grow, according to Agricultural Research Service (ARS) scientists in Oklahoma.

These gaps, which occur during late April and May, and again from September to November, hinder animal weight gain and wreak havoc with livestock managers’ planning and bottom lines. They often force producers to use costly cattle-feed supplements.

But ecologist Brian Northup and animal scientist William Phillips at ARS’ Grazinglands Research Laboratory in El Reno, Okla., think that perennial cool-season grasses could help fill these gaps because they have longer growing seasons than the region’s primary forages, and would allow calves to gain weight year round.

Each year, more than 6 million beef calves are transported through the southern Plains, where they gain weight by grazing the region’s nutritious pastures before entering feedlots. It’s all part of a system that relies primarily on annual cool-season grass such as winter wheat (Triticum aestivum) and perennial warm-season grasses such as bermudagrass (Cynodon dactylon) for forage.

The scientists have focused on three cool-season grasses not normally used in the region, but regularly used as forage elsewhere. These include Lincoln smooth brome (Bromus inermis), which is used extensively in northern Great Plains states, and Jose tall wheatgrass (Thinopyrum ponticum), which was developed in southern Australia and has been used in U.S. intermountain regions. They also studied Manska intermediate wheatgrass (Thinopyrum intermedium), which is used as forage in the Dakotas.

According to Northup, a challenging aspect regarding these grasses’ use is the economic impact of getting them started. He explained that all perennial cool-season grasses require an initial one-year establishment period, during which they shouldn’t be grazed. This drastically increases production costs.

Read more about the research in the December 2005 issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture's chief scientific research agency.