Livestock producers and horse owners who use summer annuals for grazing and/or haying are thinking about what to plant this year. Due to drought in the seed producing areas, the prices for summer annuals have practically doubled from last year. Even so, most producers will still plant the old standards, pearlmillet or sorghum-sudan hybrids, out of necessity. Some producers are now planting crabgrass, but that seed has gone up in price as well.
Pearl millet is probably the annual of choice by most livestock producers. It is leafier than sorghum-sudan hybrids and doesn’t present the risk of prussic acid poisoning. Millet grows 3 to 8 feet tall with peak production during the months of June, July, and August. It is excellent quality forage containing 14 to 18 percent crude protein and 60 to 65 percent digestibility. Once allowed to head, millet is less palatable and animals consume mainly leaves. The dwarf varieties are easier to manage for grazing, as there is less stem with the same number of leaves as the taller types. Seeding rates for millet are 20 to 25 pounds per acre broadcast, 15 to 20 drilled, and 6 to 10 in rows. Some research done at Clemson suggests you can use 10 pounds per acre in 30 inch rows and see no loss of performance with the cattle. They would walk down the middles and eat the forage on each side.
The sorghum-sudan hybrids and sudangrass usually yield more than pearl millet on heavier soils. The hybrids grow 4 to 8 feet tall. Sudangrass is shorter with finer stems. Again, peak production is June, July, and August. Forage quality is good, usually 15 percent protein and about 60 percent digestibility, with high dry matter intake. Varieties out now known as brown midribbed, or BMR, seem to offer the best forage quality. The potential for prussic acid poisoning does exist from all varieties of sorghum-sudan hybrids and sudangrass. Avoid grazing young seedlings, young regrowth shoots, stunted growth, and frosted plants. There is no danger of prussic acid from feeding hay or silage from these plants. Seeding rates for these are 35 to 40 pounds broadcast, 20 to 30 drilled, and 15 to 20 in rows.
Getting the most use from these forages can sometimes be a difficult proposition. They need to be grazed from 14 to 24 inches tall down to around 6 or 8 inches. Intensive grazing will help keep them at the proper height as will mowing and splitting nitrogen applications. Mowing of stalks after grazing may be needed too. If cut for hay, these summer annuals should be cut when growth is 30 to 40 inches tall. If bermudagrass is available, producers should consider grazing the annual and cutting the bermudagrass instead.
More producers are utilizing crabgrass as summer forage. The two varieties that are available are Red River and Quick-N-Big. While it won’t tolerate wet feet, crabgrass is well adapted to most soils, is drought tolerant, and responds to moisture quicker than most other summer annuals. It produces good growth from June to September with yields ranging from 3 to 5 tons per acre. It is highly palatable and usually higher quality than bermudagrass. Digestibility ranges from 62 to 72 percent and protein from 7 to 18 percent depending on stage of growth and nitrogen fertilization.
Crabgrass can be seeded into a prepared seedbed immediately after the last spring frost. Disking or other tillage during the dormant season seems to be necessary for productive reseeding. Nitrogen is most efficiently used in split applications at 50 to 75 pounds per acre two or three times during the growing season. An initial pre-emergent nitrogen application is very beneficial to stand development and productivity. Graze when grass is 4 inches tall. If natural reseeding is desired, the stand must be allowed to produce seed sometime during the summer. This works best with rotational grazing.
One last comment, some producers may be considering other millets such as browntop or foxtail due to these products being somewhat less expensive than pearl millet. These varieties are also much less productive. They are lower growing with smaller stems and are probably more suited to sheep, goats, and possibly horses. However, foxtail should not be used for horses as it contains a toxin that can cause kidney and joint problems. Seeding rates are similar to those for pearl millet.