Sorghum is a tropical grass grown primarily in semiarid and dry parts of the world, especially in areas that are too dry for corn. The diverse range of climates that sorghum can grow in, as well as the fact that it is heat and drought tolerant, makes it an important cereal crop. That’s particularly true in dry regions of the world.
Nutrient composition of forages reported by a commercial laboratory from New York shows that the average content of starch in sorghum silage is less than that of corn silage (10 percent versus 32 percent of dry matter or DM, respectively). It also has greater fiber (neutral detergent fiber; 58 percent versus 44 percent of DM) and lignin content (5.4 percent versus 3.3 percent of DM). Altogether, sorghum silage has a lower energy content (net energy for lactation: 0.54 Mcal/pound versus 0.73 Mcal/pound of DM) than corn silage.
For this reason, it is difficult to meet the nutritional requirements of high-producing cows when feeding significant amounts of conventional sorghum silage in the diet.
Look to BMRs
However, forage sorghum hybrids with the brown midrib (BMR) gene have shown positive results in lactating cow diets. They are becoming popular in the U.S. because they feature the lower water requirement of conventional sorghum compared to corn. Researchers from the University of Georgia analyzed the production response of lactating cows to diets based on corn or dwarf BMR sorghum silage harvested from two crops during two seasons.
Continue reading this article published in Hoard’s Dairyman.
