Now that first harvest of forage crops is completed or in progress, some may be noticing the low yields in damaged forage stands, or they may realize the need for additional forage supplies this summer. There is always the temptation to no-till something into existing stands in an effort to produce more tonnage, but I believe that is a risky proposition this time of the year. The existing stand will compete heavily for moisture and regrowth of the existing stand will shade new seedlings struggling to get established. So at this point in the year, I think it is best to either kill a poor stand and seed an annual crop for summer forage production, or find open land available to seed an annual forage for supplemental feed.
There are several good options for producing supplemental forage from annual crops planted in June, which are discussed here. Additional options for supplemental forage exist for planting in late summer, particularly following wheat harvest. Those options were discussed in an article available at http://corn.osu.edu/newsletters/2012/2012-24/#7.
For anyone considering forages for silage, corn should be the first choice because of its high yields and energy content. Corn can be planted as late as mid- to late June for silage production; however, it does carry increased risk especially if dry weather develops. Nevertheless, June planted corn with adequate rainfall can produce more forage with greater feeding value than other summer annual grasses. If forage is needed before the ear is formed, corn can be green chopped. Even without the ear, the feeding value of corn is at least equal to that of the other summer annual grasses and yields are likely to be higher.
Summer annual grasses
Sudangrass, sorghum x sudangrass hybrids, pearl millet, and forage sorghum grow rapidly in summer. When managed properly, these grasses can provide good quality forage. All these species can be planted up to mid-July and will produce 3.5 to 5 tons of dry matter per acre assuming sufficient moisture is present for emergence and growth. Pearl millet is essentially free of prussic acid poisoning potential, while the sorghum species have the potential for prussic acid poisoning which varies by species. Nitrate toxicity is possible with all summer annual grasses. Refer to the Agronomy Guide (pages 111-114) for how to reduce these risks and for more details on establishment and management (http://agcrops.osu.edu/specialists/fertility/fertility-fact-sheets-and-bulletins/agron_guide.pdf/view).
Mixtures of summer-annual grasses and legumes such as field peas and soybeans are marketed by some seed dealers. The legumes generally improve protein content but only in the first growth when they are present. Because the legumes usually increase the seed cost, evaluate the cost to benefit ratio of purchasing mixtures with legumes vs. supplementing livestock with other protein sources.
Teff is a relatively new warm-season grass option that can be used for hay, silage, or pasture. In our test plots it produced about 3 to 4 tons of dry matter per acre from 3 cuttings (http://oardc.osu.edu/forage2008/table14.asp, http://oardc.osu.edu/forage2009/table11.asp). It can tolerate drought-stressed as well as waterlogged soil conditions. For more details on managing this forage, see an excellent factsheet from Cornell University found at http://nmsp.cals.cornell.edu/publications/factsheets/factsheet24.pdf.
Soybean can be grown for forage, but it is extremely difficult to make good soybean hay and ensiling soybean also has problems. The high concentration of fat (about 10%) inhibits bacteria in the silage and fermentation is slow and often incomplete. The best approach to using soybeans as a forage is to mix them with corn plants during silo filling. A mixture of 1 part or more of corn to 1 part soybean works well. In large diameter upright silos, adequate mixing usually occurs when one load of corn is unloaded followed by one load of soybeans. In smaller diameter upright silos one-half load of soybeans followed by one-half to a full load of corn will usually result in adequate mixing. For silo bags, mixing is difficult. The ratio of corn to soybeans should be increased and the amount of soybeans put in the silo at one time should be small. The best solution would be to chop about one-fourth to one-half load of soybeans and fill the rest of the wagon with corn. Use of herbicide-treated soybeans for forage or hay is allowed for only a few herbicides, so check chemical labels before using herbicides on soybeans to be used for forage.
Several brassica species can be planted in May for late summer grazing. For more information on this option, refer to The Ohio Agronomy Guide, pages 114-118.