Articles on forages, animals, and grazing systems
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Master Grazer Coordinator
821B W.P. Garrigus Building
University of Kentucky
Extension Forage Specialist
University of Kentucky
Phone: (859) 257-3358
Fax: (859) 323-1952
Alfalfa is one of the most popular forage crops grown in the U.S. This high quality forage can be used for hay, silage, be a useful forage for animals with high nutrient needs. Although alfalfa is a cool-season legume, its deep root system makes it more drought tolerant than other cool-season species. Alfalfa can provide a high quality forage, green-chop, or pasture. This versatile crop can tolerate a wide range of soil and climatic conditions, and has the highest yield potential and feeding value of all perennial forage legumes. Because of its nutritive value, alfalfa can be a useful forage for animals with high nutrient needs. Although alfalfa is a cool-season legume, its deep root system makes it more drought tolerant than other cool-season species. Alfalfa can provide a high quality forage, even in conditions when cool-season grasses are experiencing “ summer slump” and growth rates have slowed.
Alfalfa is most often harvested for use as a stored feed, but grazing this forage can be an effective way to feed animals while reducing harvest costs. Grazing this crop can lower the use and cost of machinery and equipment. Grazing can lower fertilizer expenses as nutrients are recycled back onto the field. When pastures are grazed, up to 80 percent of the nutrients are returned to the soil as manure and urine, but when cut for hay or silage, a large portion of plant and soil nutrients are removed from the field. When used in a stand mixed with grasses, grazing can lower nitrogen needs. Taking steps to promote uniform grazing will result in better manure distribution and increase benefits of nutrient return.
Alfalfa stands can be used strictly for grazing or can be used for both haying and grazing. If managed properly, using a system where a stand is used for both grazing and hay does not reduce total yield. By grazing alfalfa in the early spring, the harvest of the regrowth can be delayed until weather conditions are more favorable for the curing process. Often older hay fields are used for grazing to extend the use of the stand. Especially ones that have become undesirable for hay production because they are thinning or have become weedy. Grazing alfalfa may also rejuvenate some stands by reducing grass and weed competition. Some producers routinely over-seed older thinning stands with cereal rye or annual ryegrass to provide high quality grazing in the fall and the following spring. Then the stand is rotated out of production the following summer. Those looking to add a couple more years to the stand may interseed with orchardgrass or another cool-season grass.
To maximize yield, quality, and stand life, alfalfa should be grazed using a rotational grazing method. Giving this crop a rest period is vital to keeping a healthy stand. If grazed continuously, stands will decline and weed and other plant populations will increase. To protect new shoots, animals should not be kept on one paddock for more than one week and the stand should be allowed four to six weeks of regrowth time before grazing again. As with any forage crop, alfalfa stands need to be well established before grazing and should not be overgrazed. Begin grazing when plants are in the bud stage and move animals to a new area when there is two to three inches remaining. Alfalfa should be grazed relatively short so that regrowth will occur from the crown and not the stems.
There are a few disadvantages of grazing alfalfa. First, there is a potential for bloat. If certain precautions are taken, this risk can be greatly decreased. For more information on reducing the risk of bloat, see Managing Legume-Induced Bloat in Cattle (ID-186). Second, the crowns of alfalfa can be damaged by hoof traffic when pastures are wet. To protect the stand, it is suggested that animals be removed from alfalfa stands under muddy conditions. Damage to crown shoots can also occur if cattle are left on an individual paddock after new shoots begin to develop. Additional fencing may be required to subdivide pastures so cattle will be restricted to one paddock, then moved to another paddock, allowing the alfalfa a rest period.
A common mistake made when using alfalfa for grazing is the variety chosen. Often new varieties of alfalfa are selected for hay production, and are less tolerant to graz-ing stress and hoof pressure. In the early 1990's grazing type varieties began to be developed that would withstand higher grazing pressure. Grazing varieties have deeper crowns protecting them from hoof traffic. The latest information on the performance of grazing tolerant varieties is available from all UK County Extension offices; see UK Alfalfa Grazing Tolerance Reports at http://www.uky.edu/Ag/Forage/ForageVarietyTrials2.htm. Review each year's report for detailed information on stand survival or see the grazing alfalfa section of the Long Term Summary Report for a summary of a list and ranking of the varieties that have been tested for Grazing Tolerance in Kentucky over the last 15 years.
Alfalfa is a high yielding, high quality forage legume well adapted to Kentucky and can provide great animal perfor-mance per acre when man-aged properly. Grazing alfalfa is a great way to extend your grazing season. For more information about how to use alfalfa in your grazing system see Grazing Alfalfa (ID-97).