Source: North Dakota State University
John Dhuyvetter, Area Extension Livestock Specialist
North Central Research Extension Center
Beef cows are generally wintered most economically on rations consisting primarily of roughage. Grain, however, provides a concentrated highly digestible source of energy that can be fed when roughages are in short supply, and high priced relative to grain, or when forage is inadequate in quality to meet cow needs to maintain desired condition. Various grain processing by products such as screenings and mids can also be well utilized in cow rations.
Kind of Grains to Feed
Choice of grain generally depends on local availability and price per nutrient provided. Table 1 lists the nutrient composition of various grains and an approximate equivalent price per bushel based on energy content. Barley, however, is often the least-cost grain in most areas of North Dakota and has the advantage of a higher protein content than corn. Corn has the highest energy value and is likely the most economical grain in corn-producing localities. Corn, oats, and barley are the primary grains fed to cattle. Oats, which has a lower energy value due to its high fiber content, is considered the “safest” grain in regards to potential digestive disturbances. Wheat and rye are sometimes fed when the price is competitive as may be the case with discounted, damaged, or inferior grades. Rye tends to be less palatable than other grains, and wheat should be limited to small amounts or fed in mixtures with oats or corn to minimize digestive problems. The nutrient value of sprouted grains remains high, and vomitoxin in grain appears to be well tolerated by cows in good shape. Grain that has gone out of condition with obvious mold growth may cause adverse health effects.
|Table 1. Nutrient composition of various grains.|
|Grain||TDN||Crude protein||Crude fiber||Lbs. per Bu.||Approximate value to corn on Bu. basis|
Processing of Grain
Digestibility of grain is generally improved by mechanical processing such as rolling or grinding to break the seed coat. Improvements in efficiency for barley and wheat will most generally offset additional costs. Depending on processing costs and the level of grain being fed, the advantage to processing oats and corn may be marginal. It is preferable to coarsely process grain. Shattering of dry grains as they are ground fine contributes to small dusty particles that can contribute to feeding losses if feed is delivered on the ground and in the wind. Fines also contribute to faster fermentation in the rumen and a greater potential for digestive problems.
Potential Digestive Problems
Grain should be slowly introduced into rations when cows have been on forage and are not accustomed to eating grain to allow microbial populations to adapt to grain. This is accomplished by limiting grain initially to a few pounds per cow per day and then increasing in small steps with four or five days between steps if additional grain is desired. Cows that over eat on grain may encounter digestives disturbances as rumen acidosis with the associated problems of founder and diarrhea. If the grain is introduced gradually and delivered so all cows have an equal opportunity to get their share, these problems are generally minimal due to high levels of roughage often being fed with small amounts of grain. If grain feeding is discontinued and later resumed a similar step up is needed.
Negative Effects on Forage
Grains are composed largely of starch rather than fiber. The populations of rumen microbes that most effectively break down fiber and ferment starch vary and prefer different rumen pH levels. As increasing levels of grain are fed rumen pH drops and a resulting decrease in the breakdown and digestion of fiber can occur. The negative effects are greatest with low quality forages and higher grain levels which may result in reduced forage intake. The reduction of forage intake and substitution effect of grain is of minor concern when hay is being severely limited to stretch supplies and grain is being substituted as a primary feed source. However, if grain is being fed to meet a marginal energy deficiency while maximizing the use of forage, grain levels should be limited to avoid offsetting supplementation effectiveness through corresponding decreases in forage digestibility and intake.
How to Feed
Grain should be fed to cows on a regular daily schedule and must be delivered so each animal gets an equal opportunity to eat. Depending on herd size, and level of grain being fed, a variety of delivery and handling methods can be used, including pails, loaders, feed wagons, and a variety of home built and commercial feed dispensing hoppers. Grain can be very effectively incorporated into mixed rations where silage and chopped forages are being fed with a mixer wagon. When grain is fed alone it is best be placed in bunks if possible to minimize waste. When clean frozen or snow covered ground is available grain may be spread in small piles on the ground. Where facilities are available, sorting the herd into smaller nutritional need groups will help limit the amount of grain needed to meet total cow herd requirements.
Provide a Balanced Ration
Grains are high in carbohydrates and fed primarily as a source of energy. The protein content of grains is moderate, and while contributing to meeting protein needs, may not adequately supplement protein when fed with low quality forage. Grains also tend to be low in some minerals, especially calcium, and tend to have low vitamin A activity. Therefore, if cow rations are made up primarily of low quality roughage and grains it will be important to also supplement protein, vitamins, and minerals. This can be done by separate supplementation or inclusion of minerals, vitamins, and high protein supplements as canola or soybean meal into the grain mixture as needed to provide a balanced, adequate ration.
Grain as a Forage Supplement
In situations where the forage supply is adequate but quality is too low to meet nutritional needs, the ration may be supplemented with a low level of grain. The objective is to allow cows to get maximum utilization and nutrition from forage while using grain to make up a marginal deficiency for energy. By limiting grain to a few pounds per cow, the negative effects of starch fermentation on fiber digestion are small. The small contribution of protein from the grain will be inadequate to correct significant shortages if forage protein is low. It will be important to simultaneously supplement protein if this is the case to stimulate high forage intake and digestion and meet protein needs. This strategy is best implemented before cow condition has greatly suffered or over a significant time period to gradually recondition cows.
Grain as a Forage Substitute
In situations where forage is in short supply, costly, or unavailable, grain may be fed to partially replace roughage. While grain usually costs more per pound then hay, it is fed in smaller amounts due to its higher nutrient composition and can sometimes be more economical. Table 2 lists the amounts of various hays that can be replaced with various grains based on differing energy values. It is advisable to substitute grain for only a portion of the roughage for several reasons; 1) some roughage is needed in the diet for proper rumen function, 2) heat produced from fiber breakdown is beneficial in maintaining body temperature, 3) fill contributes to satiate, and 4) there are feeding and management problems associated with limit feeding high concentrate rations. Under cold conditions a minimum of ¾ to 1 pound of hay per 100 pounds of body weight is suggested along with grain being fed. In addition to feeding higher levels of grain as a substitute for hay, heavy grain feeding may be appropriate when relatively high rates of gain are desired for reconditioning thin cows.
|Table 2. Energy value of grains compared to hays.|
|Grain||Prarie Hay||Sorghum Suden||Alfalfa||Mixed|
|47% TDN||56% TDN||60% TDN||53% TDN|