Grazing Alfalfa

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Harvesting alfalfa by grazing with livestock can be profitable for experienced producers who utilize critical management practices. Producers who are unfamiliar with managing livestock on lush forages should be extremely careful and attempt grazing only on a small scale. Without proper management, losses of livestock due to bloat can become quite costly. Grazing has been reported to shorten the life of alfalfa stands, compared to harvesting alfalfa for hay; however, if proper management practices are followed, grazing effects on stand life are negligible.

For most alfalfa production situations, grazing during fall and winter has more advantages than disadvantages. Spring grazing, however, is difficult to manage for most producers, and successful summer grazing can be considered intermediate from the standpoint of both positive and negative aspects. Considerations to be taken into account when determining whether to graze alfalfa follow.


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Positive Aspects 

Some reasons to consider grazing alfalfa include:

In spring, harvesting alfalfa by grazing can reduce weather-related problems associated with normal timing of first harvest (late April and early May). First-cutting hay yields are normally high, resulting in large windrows. The hay is difficult to dry and frequently requires 5-10 days without rain. As a result, most first-cutting hay is damaged by rain before it is dry enough to bale.
Alfalfa grazed in late March or early April is not ready to harvest again before May 15 to 20 under normal conditions. By that time, the frequency of rainfall is likely to be lower, and temperatures are higher; thus, hay dries more rapidly with less chance of rain before baling. Furthermore, the volume of hay is reduced and should be easier to cure.
In spring, producers often need high-quality forage for stocker cattle that were maintained on wheat pasture during winter. Alfalfa can be used for this purpose, and average daily gains may be comparable to those on wheat (frequently from 1.7 to 2.3 pounds per day).
Grazing alfalfa infested with weevils and/or aphids during spring can reduce the habitat available to the insects and results in mortality of large numbers of insects, greatly reducing the need for insecticide application. The highest mortality of alfalfa weevil and aphids results with spring grazing.
Summer grazing is especially attractive when hay yields are low during July and August due to dry conditions. Summer grazing also is a good way to utilize thinning stands infested with grasses and other weeds. Normally, forage nutritive value of these weeds is good, and grass in alfalfa reduces the chances of bloat.
In late fall and winter, grazing is the most effective and economical means of utilizing late-season forage. Late fall and winter grazing is a good means of reducing alfalfa weevil infestations by effectively reducing sites for weevils to lay eggs.  Additionally,  livestock will consume existing eggs in alfalfa stems.


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Negative Aspects

Grazing alfalfa during active growth is a challenge, and there are concerns associated with this practice. Therefore, few producers in Oklahoma routinely graze actively growing alfalfa. Some of the major concerns include:

Bloat: Fear of losing animals to bloat is the most frequently cited reason for not grazing alfalfa. Lush alfalfa growth in early spring is the most likely period for bloat to occur. All alfalfa varieties can cause bloat, including those called "grazing alfalfa." Careful management of animals can minimize bloat problems. Bloat is less prevalent during the summer; nevertheless, precautions should be taken to guard against it. Accepted practices to lessen the occurrence of bloat are listed in Figure 7-1.

 

Figure 7-1. Practices to lessen the occurrence of bloat when grazing alfalfa.

Do not put hungry cattle on lush alfalfa.
Fill animals with dry grass or hay before grazing alfalfa.
Provide a bloat preventative (such as poloxalene) for several days before and after the start of grazing alfalfa.
Closely watch cattle several times a day at first.
Give cattle a choice of eating dry feed or fairly mature grass when grazing alfalfa.
Some producers use a "chronic bloater" in the herd as an indicator.
Remove all animals from the alfalfa at the first sign of bloat and watch closely.
Do not turn cattle onto alfalfa wet with dew. Wait until it dries completely.
Do not begin early in the morning. Fewer problems occur when starting in the afternoon.
Pay close attention to weather forecasts and remove animals before weather changes.
Do not graze alfalfa that is lightly frosted.

 

Inconsistent animal performance: Weight gain depends on many factors including animal type, previous nutrition, forage availability and quality, and environmental stress (heat, cold, mud). Management of livestock and the grazing system has a tremendous impact on many of these factors. For example, animals forced to consume low-quality, mature alfalfa frequently gain less than one pound per day.  Intensive management and favorable weather conditions are required to maintain maximum animal performance.
Stand loss: Removing animals when the soil is saturated to the point where animals leave deep tracks can minimize stand loss problems (another reason for not grazing alfalfa). Rotational stocking or mob grazing (high stocking density for a day or two) to remove forage quickly normally results in no stand loss problems as long as adequate rest periods between harvests are provided.
Grass and weed infestation: Grazing alfalfa in early April can increase the amount of cool-season grass in the second alfalfa harvest. Vigorous alfalfa often smothers grasses during April. However, removing alfalfa allows light to reach the grasses that are then able to compete with alfalfa and produce seed. If weed-free hay is the target for second harvest, then weeds should be controlled with a selective herbicide before grazing.


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Grazing Practices during the Growing Season

There is no single acceptable practice for grazing alfalfa. Both continuous and rotational stocking is possible and can be successful if managed properly.

To reduce the chances of damaging stands and to maintain stocker gains between 1.5-2.0 pounds per day, some type of controlled or rotational stocking should be practiced. There is no set rule on the number and size of paddocks; however, paddocks should be small enough for animals to complete grazing in less than a week. Ideally, allow 4-5 weeks for recovery before another round of rotational grazing begins. A good program would be to divide the field into eight paddocks and graze each area four days. To prevent damage to the stand, cattle should be removed when fields become muddy.
Rotational stocking (grazing less than five days followed by regrowth for at least 3 weeks) will result in high forage production and animal gains. In general, good hay-type varieties respond in the same way to rotational stocking as to cutting for hay.
Rotational stocking can minimize the ill effects associated with thinning alfalfa stands because of grazing. Animals should not be left on any particular part of the field longer than one week. If animals remain on the field longer, much of the available forage is lost by trampling, and new regrowth will be eaten. Rotational stocking should alleviate both of these problems. The best combination of days of grazing and regrowth changes during the growing season because alfalfa grows at different rates. It matures most rapidly when temperatures are high ( 90o F and higher) and there is adequate moisture.
Continuous stocking of hay-type alfalfa (and probably grazing types) should be managed so alfalfa is not grazed shorter than 6 inches. This means stocking rates are adjusted several times during the growing season by removing and introducing animals as dictated by alfalfa growth rate.

Research at the Grazinglands Research Laboratory at El Reno, OK, has shown continuous stocking is a good method for grazing stockers, resulting in gains exceeding two pounds per day using a well-adapted hay-type alfalfa variety. However, many producers find this system difficult because of the need to divide the herd and adjust stocking rates with each change in growing conditions.


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Economics of Grazing during the Growing Season

A strong argument for grazing alfalfa is the reduced cost of harvesting. Stocker gains of 1.5-2 pounds per day are attainable. Alfalfa yields of 0.75 ton per acre (grazable) can be assumed in early to mid-April. Assuming stockers consume 15 pounds per head per day, 100 stocker-days per acre are present in typical alfalfa stands. Allowing one week to consume available forage, approximately 14 head per acre would be used, gaining 14 pounds per acre on average. At $.30 per pound of gain, almost $59 per acre could be earned during a one-week grazing period. Cost of grazing would include fencing, labor, poloxalene, and dry hay for bloat control.

Economic return is also a reason for interest in summer grazing. Cutting, raking, and baling cost approximately $21 per acre per cutting. If weed-free hay sells for $80 per ton and grazable summer yields are 0.5 ton per acre, only $14 per acre would remain after harvest and hauling costs. With grazing as an alternative, assuming one pound of gain for each ten pounds of forage, 100 pounds of beef gain could be achieved. One hundred pounds of gain would be worth $30 per acre at current rental rates ($.30 per pound gain). If a producer owns the cattle, a higher return could be achieved.

In late summer, instead of making hay, a better option may be to graze droughty alfalfa. Grazing is the least expensive way to harvest alfalfa. When alfalfa is droughty in the summer, bloat problems are easily controlled. During late summer, when alfalfa stops growing, mob grazing can be a very good way to harvest.

Stockers can gain between 1.5-2 pounds per day on this type of forage. Considering 600 pounds per acre of alfalfa are present and stockers consuming 15 pounds per day, there are about 40 stocker-days of forage per acre. Stocking at four stockers per acre, the field can be cleaned in 10 days. If the cattle gained 1.76 pounds per day worth $0.30 per pound of gain, the forage is worth about $21 per acre, about the same as the value of hay, without harvesting equipment costs. As with spring grazing, cost of grazing includes fencing, poloxalene, and labor.


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Late Fall and Winter Grazing

Mob grazing alfalfa after the first killing frost (20°F) in November or December is likely to be a better option than trying to make hay. Making hay during this time is difficult because of poor drying conditions-- i.e., low temperature, high relative humidity, and reduced solar radiation.

Another consideration is the value of the hay. The value of hay would be about $40 per acre (gross), assuming 0.5 ton per acre (grazable) at $80 per ton. When harvesting cost is approximately $21 per acre, only $19 per acre remains to cover costs of hauling and storage. This optimistically assumes the hay is baled before it is damaged by precipitation. Grazing would cost much less than haying, assuming no loss due to bloat. Using a grazing value of $60 per ton, the 0.5 tons per acre yield would be valued at $30 per acre. Expenses of grazing include bloat prevention, fencing, and labor.

Grazing after frost also helps control insects. During grazing, sites for alfalfa weevil eggs are removed and eggs in stems are consumed, reducing the number of eggs available for hatching the following spring. Grazing on dry fields after a hard freeze will also result in some control of broadleaf weeds. Further, the hoof action of the livestock will cause uprooting of small weeds. See Chapter 2, "Insect Management - Alfalfa Weevil" for details.


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Pasturing Dairy Cattle

Recently, some dairy producers have taken another look at grazing for their lactating herd as a way to make more effective use of their land and reduce operating costs. The key to success in grazing alfalfa with dairy cattle is to manage the fields in a grazing system with adequate periods of rest to allow for proper regrowth. The following are suggestions producers should follow to reduce potential problems and provide effective grazing.

To reduce the potential of bloat during spring grazing, cows should be fed before being allowed access to pasture. An additional precaution may be to limit access to the pasture. Over a period of one to two weeks, cows may be allowed access for increasing intervals until animals are on pasture continuously. Once adapted, bloat usually does not occur unless cows are forced to graze pastures too closely and are hungry when moved to the next paddock.
Move cows to new paddocks frequently in order to ensure high-quality forage is available daily. Low-producing cows, heifers, and dry cows may be allowed to graze after the high-producing cows to clean up pastures and make use of the  lower-quality forage.
Grazing may provide 40 to 50 percent of total dry matter intake. The remainder of intake can be used to balance the ration.
High producing cows may need some source of rumen-undegradable protein (e.g., blood meal, fish meal, etc.) to meet protein and amino acid requirements for high production.
Feeding high-starch feeds such as corn will help "capture" the soluble protein portion of alfalfa and increase rumen microbial protein production.
Feeds such as soybean hulls, whole cottonseed, wheat midds, or corn gluten feed may also be incorporated into the grain mix to provide appropriate levels of highly digestible carbohydrate while providing a source of fiber. Additionally, some hay also may need to be fed to maintain fiber levels in the ration and to prevent digestive upsets and milk fat depression.

Pasture based dairy operations can achieve excellent production levels while controlling input costs. However, close attention to detail, proper supplementation, and use of rotational stocking are needed in order to realize maximum benefit from an alfalfa grazing system.


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Alfalfa Production Guide for the Southern Great Plains, 2001
Comments and Questions:
E-mail: John Caddel


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