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FORAGE SPECIES FOR SUPPLEMENTAL EMERGENCY FORAGE

FORAGE SPECIES FOR SUPPLEMENTAL EMERGENCY FORAGE

 

Mark Sulc

Dept. of Hort. & Crop Sci., The Ohio State Univ., Columbus, OH

Bill Weiss

Dept. of Animal Sciences, OARD/OSU, Wooster, OH

 

Many Ohio livestock producers are faced with or will likely soon face a need for supplemental forage to offset decreased or lost production from winter-injured alfalfa stands. The need for such supplemental forage is already apparent in many cases. The need for supplemental forage may become even more apparent, because some winter-damaged stands of alfalfa may fail to recover satisfactorily after the first harvest.

 

Earlier this spring, small grains and small grain-pea mixtures could have been planted. Now, and certainly after the first harvest, our options for planting supplemental forage are limited to the summer annual grasses and legumes. Below is a brief description of these forage species to consider. Refer to the Ohio Agronomy Guide, 13th Edition, for more information on establishment and management of these crops. Feeding these forages should be based on forage quality analyses and ration balancing to meet the herd's nutritional and energy requirements.

 

Corn

 

Corn silage is the best choice in terms of yield potential and feeding value of all annual forages grown in Ohio. Late planted corn (in June) for silage will be lower yielding than if planted earlier in May, but yield potential and feeding value are still higher than for the other summer annual grasses discussed below. If forage is needed before the ear is formed, corn can be greenchopped. Without the ear, feeding value will be at least equal to that of the other summer annual grasses, and forage dry matter yields are likely to be higher with corn. This offers some flexibility for producers who may need to extend their forage supplies in late summer before the corn is ready for silage harvest. Some acres could be greenchopped, and the rest saved for silage harvest at the recommended kernel milkline stages when corn reaches 30 to 40% dry matter content. Earlier maturity hybrids may be an option for reducing the time to corn silage harvest; however, we have no data on silage yield potential of very early season corn hybrids.

 

Summer-annual grasses

 

These grasses grow rapidly in late spring and summer, and when managed properly can provide forage of good quality. Summer-annual grasses are a good double-crop option when planted after a small grain crop. With the exception of pearl millet, the summer-annual grasses are members of the sorghum family. These species differ in prussic acid poisoning potential (see below), but all are equal in nitrate toxicity potential.

 

Sudangrass is fine-stemmed, leafy, and grows between 3 to 8 feet tall. It will regrow following each harvest until cool temperatures or lack of moisture inhibit growth. It is the preferred summer-annual grass for pasture, and can be used for hay. Solid stands grow shorter than when seeded in rows. Sudangrass usually contains lower levels of prussic acid and is usually lower yielding than the other sorghum family grasses. Sudangrass hybrids are generally slightly higher yielding and have slightly higher prussic acid levels than sudangrass at comparable stages of growth.

 

Sorghum-Sudangrass Hybrids are made by crossing sorghum varieties with sudangrass. They resemble sudangrass in growth habit, but are generally taller, have larger stems and leaves, and are higher yielding. This grass can become coarse and unpalatable if not properly utilized. It is not as well suited for hay production as sudangrass. Sorghum-sudangrass hybrids will regrow following each harvest unless environmental conditions are restrictive, as with sudangrass. They are more likely to contain toxic levels of prussic acid.

 

Pearl Millet is not in the sorghum family and prussic acid is not produced in the plant. It tends to have smaller stems and be more leafy than the sorghum grasses. Pearl millet will regrow after each harvest, but not as rapidly as sudangrass or sorghum-sudangrass hybrids. It may also be more sensitive to cutting height for regrowth than sudangrass.

 

Forage Sorghum grows 6 to 15 feet tall and has potential for high yields. It is utilized as a one-cut silage or greenchop crop. Forage sorghum produces silage containing more digestible energy than legume and cool-season grass silage. Making high-quality silage from forage sorghum is generally easier than from forage legumes because of the high levels of nonstructural carbohydrates which enhance fermentation. The high-energy, low-protein characteristics of forage sorghum silage make it a good supplement for high- protein forage legumes. The feeding value of forage sorghum silage is considered to be about 85% that of corn silage; therefore, corn silage is usually the preferred high-energy silage grown in Ohio. But forage sorghum has the potential to grow better than corn on light-textured, shallow soils that tend to be droughty.

 

Mixtures of summer-annual grasses and legumes such as field peas and soybeans are being marketed by some seed dealers. The legumes generally improve protein content compared with summer-annual grasses grown alone. The annual legumes included in these mixtures would be present in the first growth only; regrowth would occur only from the grasses (except forage sorghum which does not regrow after harvest).

 

Soybeans

 

Corn silage should be the first choice over soybeans, but soybeans can provide supplemental forage with good management and provided herbicide restrictions are adhered to. Use of herbicide-treated soybeans for forage or hay is allowed for only a few herbicides, so check the label before using herbicides on soybeans to be used for forage.

 

The optimum time to harvest soybeans for hay to optimize yield and quality is when seeds are filling the pods and the lower leaves of the plant are just beginning to turn yellow. If harvested for silage at this stage, soybeans should be mixed with corn in the silo to achieve acceptable fermentation. Mix one part soybean with two or more parts of corn in the silo. If soybeans will be ensiled alone, then harvest at about 60 days of growth (before seed formation) to avoid the high oil content which inhibits good fermentation in the silo. This practice is not the best choice, because of the resulting low dry matter yields.

 

Soybean forage should comprise no more than 30 to 40% of the dry matter intake of the animal, because of its high oil content (assuming it was harvested when seeds were formed). This level will not be exceeded when soybean and corn silage are ensiled together in the proportions described above.

 

Brassicas

 

Brassica crops such as turnip, rape, kale, or swede are fast- growing crops that are good options for grazing, especially for sheep and beef cattle. These crops are highly productive, and can be grazed from 80 to 150 days after seeding, depending on the species. These crops must be treated more like "concentrates" than "forage" in nutritional planning for livestock because of their high digestibility and low fiber content. They are seldom used as dairy feed because they can cause an off-flavor in the milk. Consult the latest Agronomy Guide edition and county extension offices for more information.