Livestock producers can use summer annual forages to supplement cool season forages during the gap in summer production. Fescue and other cool season grasses shut down production during July and August, and leave producers short of grazing resources. These summer annuals are also a valuable resource as hay crops producing high tonnage and quality forage. Producers often ask what they should plant and there is not magic answer, although I’ll attempt to address some of the different options available.
While there are many options for summer forages, many do not make good hay crops due to our humidity combined with their slow drying rate. Two of the most common here in Burke County are Pearl Millet, and Sorghum/Sudan crosses or Sudex.
Pearl Millet is from Africa, and does well here in our environment. Pearl Millet is a tall, upright growing forage that recovers rapidly from grazing, or cutting and tillers aggressively if cut, or grazed at around a 6” height. Close grazing or mowing tend to set recovery back some and I recommend leaving a taller stubble height. Millet produces good grazing from June through August and should be seeded after our last frost date of May 15th, once soil is warm. It typically will render 52-58% total digestible nutrient(TDN) if managed in optimum maturity. Crude protein(CP) will usually range from 8-11%. Seeding to grazing will generally be 30-40 days and can usually be grazed until frost. Successive cuttings or grazing’s will generally drop in yield potential. Pearl Millet given proper fertilization can carry up to 2-3 mature cows or 3-4 stockers during peak production and hay yields can vary from 9-16,000 lbs. per acre. Pearl Millet resists drought better than many other species, and while it can accumulate nitrates, it does not pose a risk from prussic acid poisoning as do the sorghum-sudan crosses.
The sorghum family including forage sorghum, sudangrass, and the sorghum-sudangrass hybrids (Sudex) can also be used for grazing, and hay crops. The newer improved brown-rib varieties have improved quality and are more digestible than the older varieties. Sudex will generally be higher yielding than Pearl Millet but more susceptible to drought. Sorghum-Sudangrass hybrids typically range from 53-60% TDN and from 9-15% CP. They must be managed closely when grazing to avoid prussic acid toxicity and also will gather nitrates when suitable conditions prevail.
There are many other summer annual forage species out there, and many may find a niche in our forage program, but the Sorghum-Sudangrass hybrids and Pearl Millet have proven their worth over time, and are fairly predictable in their output, allowing producers to plan for their forage needs during the summer cool season forage gap. Producers should consider the merits of these forages and make their decision based on their needs, management, and resources, so that they can maximize their forage resources.