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Forages for Dairy Cattle

Characteristics of a Good Dairy Ration

A ration is the amount of feed fed to a cow in a 24 hour period. Good dairy rations provide the "right" amounts of nutrients to the "right" cow at the "right" time.

Forages are the foundation upon which Ohio dairy rations are built. Since dairy cows are ruminants, they need 1 to 11/2 pounds of hay per 100 pounds of body-weight per day to maintain normal functioning of the rumen and to allow them to produce milk containing a normal percentage of milk fat. Long or chopped forage will fulfill this need for fiberous feeds. Forage that has been ground in a hammermill or through a fine recutter screen has lost its effectiveness as a source of fiber. The concentrate mixture should be formulated to compensate for any deficiencies that remain after the forage intake is considered.

Most forages are high in crude fiber content and relatively low in energy. Wide variation exists due to plant species, stage of maturity at harvest, weather damage leaf loss in the field and improper storage. They are usually produced on the farm and are a source of relatively low priced nutrients. Their bulkiness makes forages difficult and expensive to transport. Some high fiber by-product feeds can be used to replace forage in times of short supply.

High producing dairy cows should be fed the best forage available. The primary factor in determining the quality of grass-legume forages is the date of cutting. The digestibility and palatability of forages decreases rapidly after the heads appear on grasses and the blossoms appear on legumes. The maximum nutritional value of a grass-legume forage is established at the moment it is cut. There is no equipment available for processing, handling, storing or feeding the forage that will improve its nutritional value. In fact, one always gets less out of a machine or storage structure than he puts into it. Dairymen should harvest forage early while the quality and yield of nutrients are high, even though the yield of dry matter per acre is not maximum. On the average, weather hazards are no greater for early harvested than late harvested forage.

Forage, depending upon its quality and the quantity consumed, will provide for the maintenance needs of a dairy cow and allow her to produce 0 to 40 pounds of milk per day. A concentrate mixture should be fed to support the production of milk in excess of the amount that can be obtained from forage alone. The concentrate mixture is fed to increase the energy and nutrient density of the ration. A ration that contains 68 to 74 percent digestible dry matter (similar to T.D.N.) will meet the energy needs of high producing cows within the limits of their ability to consume feed dry matter. The poorer the quality of the forage, the greater the amount of concentrate mixture needed.


Methods of Handling Forages

Dry Forage

Hay has been the traditional forage provided for dairy cows during the barn feeding season. Cows fed excellent quality hay free-choice consume forage dry matter at a maximum rate. Hay making in Ohio is plagued by weather problems and the operations required have been more difficult to mechanize in comparison to silage.

Hay should contain 80 or more percent dry matter (20 percent or less moisture) when it is baled without a preservative. Baling at lower dry matter percentages leads to high temperature curing and a significant reduction in protein digestibility. This reduction in protein digestibility can run as high as 30 percent. Testing for acid detergent fiber insoluble nitrogen provides an estimate of the amount of protein unavailable for digestion.

Research has shown that propionic acid is an effective fungistat. It's use according to manufacturer's directions will allow hay to be baled at lower dry matter percentages. One commercial product will prevent the over-heating of hay baled between 75 and 80 percent dry matter. This is not an extremely large change in the recommended dry matter percentage, but it does provide for an earlier start in the morning and a later finish in the evening. Sometimes it is the difference between making hay and not making hay. If this system is used, measure the dry matter percentage of the window accurately and do not exceed the manufacturer's recommendations.

Silage

Ensiling is a method of preserving forage crops. Ensiling does not improve the quality of the material stored. Under good management, dairymen can expect to recover 92 to 95 percent of the material stored in a gas-tight silo; 88 to 92 percent of that stored in a conventional silo; and 85 percent of that stored in a bunker or trench silo. Poor management can reduce all of these dry matter recovery estimates significantly. For silage to be preserved, it must be stored in an environment free of oxygen and the material must develop an adequate amount of acid to lower the pH to 4.5 or less. Fine chopping, rapid filling, and even distribution of material in a structurally sound silo are recommended. The dry matter content of the silage should be between 30 and 50 percent (50 and 70 percent moisture) to produce a good quality feed.

The quality of meadow crop silage is dependent primarily upon the kind of crop harvested and the stage of maturity at which it is cut.

Silage is of slightly less value per pound of dry matter than hay made from the same field on the same day. Cattle will eat slightly more dry matter per hundred pounds of bodyweight as hay. However, making silage entails less weather hazard, is easier to mechanize and causes less field losses.

Meadow crop silage should be cut early and chopped fine but not pulverized. Early cut silage should be wilted. For conventional silos, the recommended dry matter percentage for silage is 35 percent (65 percent moisture). Such material packs well to exclude air, seeps very little if at all, is consumed at a rate of dry matter intake per one hundred pounds of bodyweight that is similar to drier material and the moisture content helps assure a low temperature fermentation. A high temperature fermentation is caused by oxygen entering the silage and the silage having a high dry matter content (above about 40 percent). A high temperature fermentation (browning reaction) changes the material from green when ensiled to brown when removed from the silo. Such browning reactions reduce the digestibility of both protein and energy containing compounds. These reductions may be as high as 30 percent.

For gas-tight silos, wilting to 45 percent dry matter (55 percent moisture) may increase the ease of removing silage. Such silos should be filled rapidly and as completely as possible. All gas entrance control mechanisms should be closed as soon as possible. Significant browning losses have been observed in gas-tight silos that have been partially filled and/or improperly sealed. The browning reaction proceeds at maximum speed in the presence of oxygen at 70 percent dry matter (30 percent moisture) and at environmental temperatures over 100 F.

Pasture

Pasture can be a very good or very poor source of nutrients for dairy cattle. Pasture quality depends upon the plant species present, the stage of growth and the amount of material available. The area available at any one time must be controlled to maintain a legume stand in a pasture, to minimize wastage and to provide high quality forage throughout the pasture season. A sequence of different crops is usually desirable. If milk production increases when cattle are on pasture, it indicates a deficiency in the barn-feeding ration, usually a deficiency of protein. If production decreases when cattle go to pasture, it usually indicates that a more nearly balanced ration was fed during the barn-feeding period. Removing the cattle from pasture several hours before feeding the concentrate mixture will usually increase the amount of dry matter consumed and will increase milk production. Convenient sources of shade and water should be provided for cattle that are pastured during hot weather.

Green-Chop

Chopping and hauling forage to dairy cattle increases the yield per acre of meadows because the losses due to tramping and fouling are avoided. The labor, power and capital costs are similar to harvesting the crop as silage. It is usually necessary to provide a sequence of different forages to have good quality forage available for harvest each day. Rainy weather and poorly drained fields make daily harvest difficult. Harvesting the forage twice each day will reduce the heating of the material and will increase consumption.


Forage Crops

For additional information on these forages, please see our Crop - Forage pages.

Alfalfa: A good, well managed stand of alfalfa on well-drained soil produces greater yields of protein and energy than any other grass or legume crop. Alfalfa must be protected from damage by alfalfa weevils and potato leaf hoppers. Information concerning the number of insects necessary to cause economic losses and approved insecticides can be obtained from your County Extension Agent.

Birdsfoot Trefoil: Birdsfoot Trefoil is similar in composition to alfalfa. It is most useful in long-lay meadows on poorly drained soils. Its yield potential is 80 percent or less than that of alfalfa on well-drained soils. Only upright varieties should be planted if the crop will be harvested for hay. Seedling vigor is low. Stands become established slowly. It is usually seeded with bluegrass or timothy to limit the amount of competition.

Medium Red Clover: The yield of medium red clover on well-drained soils is usually less than 80 percent of that expected from alfalfa. The nutrient composition is similar to alfalfa. Occasionally, a fungus that produces a toxin called the "slobber factor" grows on late cut red clover. This toxin when consumed by cattle causes a profuse flow of saliva followed by a refusal to eat the affected forage (either hay or silage). There is no practical method of removing the toxin. The best protection is obtained by early harvesting.

Sweet Clover: Although sweet clover is similar in chemical composition to alfalfa, it is seldom harvested as hay for dairy cattle. Moldy sweet clover hay is likely to contain dicoumarol that prevents the normal clotting of blood. Animals with "sweet clover poisoning" hemorrhage severely when cut or bruised.

Soybeans: Soybeans can be used as an emergency hay crop. Forage varieties planted in thick stands develop into a finer stemmed, leafier crop than that produced by soybeans planted for seed production. Soybean hay is difficult to cure and dusty to handle.

Timothy: Timothy is the companion grass usually seeded with medium red clover. The recommended cutting dates for these species are nearly the same. Timothy also matures at a rate nearly equal to varigated varieties of alfalfa. It is seldom planted in pure stands because it does not produce well in dry weather and does not respond well to nitrogen fertilization. It is a palatable grass and will be consumed in large quantities if harvested as the heads emerge from the boot.

Brome Grass: Brome grass is a good companion grass for use with varigated alfalfas. It is rather difficult to establish and is best suited for use in long-lay meadows. It is seldom planted in pure stands.

Orchard Grass: Orchard Grass is the earliest maturing tall grass grown in Ohio. When harvested early (as the heads emerge from the boot) it is a palatable forage. Its dry matter digestibility and palatability are reduced rapidly after the heads emerge from the boots. Orchard grass responds well to nitrogen fertilization. Common orchard grass matures too early to be a good companion grass for alfalfa. The named varieties such as "Pennlate" mature 10-14 days later and can be used as a companion grass with "Flemish" type alfalfas.

Tall Fescue: Tall fescue is an aggressive, productive grass but is not as palatable as the grasses discussed above. It will be consumed in amounts adequate for maintenance diets and will support a limited amount of growth. It is not a desirable forage for milking cows.

Sudan Grass and Sorghum-Sudan Grass Crosses: These crops produce forage during the late summer and early fall when permanent meadows are likely to be dormant. No consistent superiority in yield has been found for any variety or hybrid in the three to four cut system that is necessary to obtain high quality forage. The quality is reduced rapidly as the heads emerge. The Sudan grasses are finer stemmed and lower in prussic acid than the Sorghum Sudan crosses. Neither of these crops should be grazed or chopped when less than 16 inches tall because of possible high prussic acid content.

Normal Corn Silage: A crop of corn made into whole plant corn silage yields more energy per acre than any other crop adapted to Ohio. The recommended harvest time is the late dent stage when the grain is physiologically mature and contains approximately 36 percent moisture (64 percent dry matter). The stalks at that time contain about 70 percent moisture (30 percent dry matter). At this stage the yield per acre should be maximum, the crop will chop easily, it will pack tightly and little or no seepage should occur. Corn silage should be chopped fine enough to break the cobs into particles of pea-size or smaller, but it is not necessary to break all of the kernels. Corn silage is low in protein and minerals.

Non-Protein-Nitrogen Treated Corn Silage: Corn silage harvested at 30 to 38 percent dry matter can be treated with non-protein-nitrogen compounds such as urea or ammonia to increase the crude protein percentage of the silage. Untreated corn silage contains about 8 percent crude protein on a dry matter basis (2.8 percent as fed). The addition of 10 pounds of urea or 6 pounds of anhydrous ammonia per ton of material ensiled will increase the crude protein percentage 50 percent (12 percent crude protein on a dry matter basis and 4.2 percent as fed). Non-protein-nitrogen compounds can be purchased directly or in combinations that contain minerals, vitamins or energy sources such as molasses.

Supplemental minerals are usually needed when corn silage is a major part of the forage program. They can be added to the silage at ensiling time or added to the ration as it is fed. Maximum flexibility and minimum capital costs are obtained when minerals are added as needed.

If non-protein-nitrogen compounds are to be added to corn silage, observe these recommendations:

  1. Harvest the corn crop at 30 to 38 percent dry matter (62 to 70 percent moisture).
  2. Determine accurately the amount of chopped material in each load.
  3. Add the correct amount of non-protein-nitrogen. Ten pounds of urea can be spread over the top of the load or metered in at the blower. Six pounds of anhydrous ammonia can be added as a water solution or by using a cold-flow meter. It may be added at the blower or at the field chopper. Ammonia additions should be made at the field chopper for silage to be stored in a bunker or trench silo. Do not attempt to use anhydrous ammonia directly as a gas. The loss of nitrogen is too great.
  4. Reduce the amount of non-protein-nitrogen added to the silage that will be fed first to provide a three to six week adjustment period for the microorganisms in the rumen. Silage dry matter intake will be greater and the utilization of non-protein-nitrogen will be more efficient.

The addition of high-calcium limestone to corn silage does not improve its feeding value for dairy cattle.

Mature Corn Silage: Mature corn plants should be made into silage only under emergency conditions such as inclement weather during the normal harvest time or the need to refill limited silage storage capacity. Field losses of dry matter occur after the late dent stage because of leaf shatter, stalk lodging and ear droppage These losses approach 20 percent of the potential dry matter yield as the crop proceeds to full maturity. Non-protein-nitrogen compounds should not be added to mature corn silage, because it does not pack tightly and less fermentation (acid production) occurs. Under these conditions, much of the added nitrogen is lost.

Frosted Corn for Silage: Harvesting a crop of frosted corn as silage will salvage more nutrients per acre than any other option available for a dairyman. The nutritional value per pound of dry matter harvested will be similar to that in normal corn silage. The frosted crop should be allowed to dry to a minimum of 30 percent dry matter (70 percent moisture) to prevent seepage but it should not be allowed to become overly-dry (more than 40 percent dry matter—less than 60 percent moisture).

Sorghum Silage: Forage type sorghums often produce greater yields of green material per acre than does corn. However, this extra weight is usually moisture and the yield of energy per acre is usually less. Forage sorghums should be ensiled when the seeds are in the dough stage. Such silage often seeps large quantities of juice which contain nutrients and is a water pollution hazard. Sorghum grains are not effectively broken by field choppers. A large percentage of them pass undigested through the cow. Grain type sorghums are not recommended for silage. A combination of corn and sorghum for silage is less desirable than either crop planted alone because of the difference in maturity dates.

Corn-Soybean Silage: A combination of corn and soybeans grown for silage is not a desirable crop. When the population of corn plants is adequate for maximum corn production, few soybean plants survive. If the corn plant population is reduced enough to allow soybean plants to grow, the loss of corn production out-weighs the advantages of soybean production.

Soybean Silage: Chopped green soybeans do not make good silage. They develop into slick, slimey, badsmelling silage. If immature soybeans are frosted, they should be chopped and mixed with green-chopped corn before ensiling in order to provide the necessary amount of fermentable carbohydrate necessary for proper fermentation.

Small Grain Crop Silage: Rye, wheat, barley, oats and spelt can be made into good quality silage if they are cut in the blossom to milk stage, wilted to 35 percent dry matter (65~o moisture), chopped fine, distributed evenly and stored rapidly. Small grains that reach the late dough-stage should be harvested as a grain crop.

Rye: Rye seeded between September 1 and 15 will usually provide a supply of late fall forage for grazing and/or green chopping. It will then live through the winter and provide early spring forage. It is a palatable forage until the heads appear. The fields are usually plowed and seeded to corn for silage or soybeans after the rye has been removed. Balboa is a variety recommended for use as forage.

Straws, Stover and Cobs: Oats and wheat straws, because they are at full-maturity, are usually considered bedding materials rather than feed. When fed to cattle they are likely to provide adequate energy for maintenance but may be deficient in protein and minerals. Limited amounts of clean, bright straw can be fed to producing dairy cows to maintain normal rumen function and butterfat percentage in times of forage shortages.

Corn Stover: Corn stover is equal to average quality hay in energy content. However, it is much lower in protein and mineral content. Corn stover should be harvested only from those fields of corn that were grown under conditions approved for corn silage for dairy cattle. Be sure to check the chemicals that were used to control insects and weeds. Corn stover should be stored in a manner that prevents mold growth.

Corn Cobs: Corn cobs can be used to raise the fiber content of dairy rations or as the fiber portion of complete rations for ruminants. Cobs have an energy value equal to medium to low quality roughage. They are very low in protein and mineral content. Only mold-free cobs should be fed.


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This page was last updated on November 16, 2002