Two new traits that have been bred into some types of summer annual forages give producers more choices in the types of forages they can grow. The traits have been developed by researchers in several states for grazing, haying and silage.

Research done by Texas A&M University in 2002 showed forages that incorporated photo period-sensitive (PPS) and brown mid-rib (BMR) traits generally produced better yields than did corn silage. Both traits have been developed in sorghum, sorghum-sudan grass and hybrid pearl millet. The BMR trait can also be found in corn.

"The PPS and BMR traits have shown to have advantages over the favorite roughage source of corn silage," said Ron Hale, livestock specialist for Kansas StateUniversityResearch and Extension in southwest Kansas.

Research into these traits has been conducted in several states. Texas A&M has been the leader over the last few years, with a large number of varieties and types, water use efficiency and some feedlot and grazing work. Kansas State has studied comparisons of summer annual forages for a number of years at various locations across the state. Oklahoma State University, Purdue University, the University of Wisconsin and the United States Department of Agriculture Dairy Forage Research Center have also researched PPS and BMR traits.

The PPS trait is sensitive to sunlight and as days grow shorter (less than 12 hours), plants with this trait go from the vegetative phase of their life cycle to the reproductive phase. Plants with the PPS trait have shown higher forage growth, which is a strong attribute to the plants.

The downside of the PPS trait, however, is that the growth of the plant is dependent upon the lignin content to hold the plant up. Lignin reduces digestibility of the plants.

K-State's Hale said forages that contain the PPS trait have a higher yield potential and better water use efficiency than does corn for silage, which may make using forages with PPS more feasible and economical to use. With the high lignin content in PPS plants, however, the energy content is lower than with corn silage.

That can be fixed when feeding PPS forages by supplementing them with grain, he said.

The brown mid-rib (BMR) trait has the opposite effect on a plant from plants containing the PPS trait. Plants containing the BMR trait have 25 to 50 percent lower lignin content than non-BMR forages.

That means improved energy and digestibility of BMR-containing forages compared with forages that do not contain the BMR trait, Hale said.

"This trait may be good for growing and dairy rations because any improvement in energy and digestibility has a big impact," said Hale. "The rate of gain in cattle feed BMRs may be equal or better than corn silage."

The drawback to the BMR trait is that there is lower forage growth than with forages containing the PPS trait, as well as lodging problems associated with the lower lignin content.

Texas A & M University has tested varieties that are more resistant to lodging than others.

"The improved quality of the BMR (forages) and higher production of the PPS (forages) provide viable alternatives for corn silage," said Hale. "This could be especially true in western Kansas where many of the feedlots and dairies rely on silage and where the aquifer water levels have been declining."

For more information contact local Kansas State Research and Extension Offices.

K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus in Manhattan.