Using drought-stressed crops as emergency forage
August 11, 2016
Much of the geographic area covered by Tri-State Livestock News has been experiencing drought conditions. This is making the job of getting enough hay and forage put up difficult for many. In my column this week, I will give you a few tips and pointers on making the most out of drought stressed field crops.
Table 1 details average composition of some of the forages I will discuss in this article. It is important to get drought-stressed feeds tested prior to feeding to ensure that you formulate a balanced ration and provide the proper nutrition for your livestock. The NDSU Extension Service has an excellent drought web site available at: http://www.ag.ndsu.edu/drought/ . The web site presents information on a variety of drought related topics including livestock nutrition and feeding programs, drought management, as well as information on crop and livestock production.
Drought stressed small grains can be harvested as hays, silages, or grazed. Crops in this category include wheat, barley, and oats. Nitrate accumulation in small grains is a major issue with each of these crops. Be sure to collect a representative sample and test it for nitrate before grazing or feeding these forages. Obviously, yield is negatively impacted by drought conditions. In many cases it may be economically advantageous to graze these forages rather than harvesting as a hay or silage. Nitrate accumulation will impact this decision.
Drought stressed corn can be harvested as silage. Depending on the severity of drought, the corn may not formed ears. In this case grain production will be zero. In well-eared corn silage, the grain makes up about 50 percent of the weight of the silage on a dry matter basis. The lack of grain will affect the yield and also reduce the energy content. The protein content, however, may actually be greater than corn silage put up under normal growing conditions, especially if the silage is chopped before the plant has matured.
Drought stressed soybeans can be harvested as either silage or hay. The quality of soybean hay is quite good, particularly if it is put up with a minimal amount of leaf loss. Typical crude protein content of this hay ranges from 16 percent to 21 percent and it has about 75 percent to 80 percent the energy content of corn silage when compared on a dry matter basis.
To harvest soybeans as silage, be sure to test the moisture content and aim for about 65 percent moisture in the silage. As the soybean plant matures and leaf drop starts to occur, forage quality will be reduced.
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Drought stressed sunflowers can be salvaged as silage. Any other means of harvest of this crop is not practical. Even in a drought, sunflower plants do not dry down enough to make hay out of the crop. To make good quality silage with sunflowers, you need to add a drier feed to the silage pile. If you don't, the effluent losses from seepage of excess moisture will be significant and costly.
In the past, producers have successfully blended corn and sunflowers together in a silage pile. One load of sunflower silage added to 3 to 4 loads of corn silage is a ratio that has worked well. Ideally, you should check the moisture content of both the corn and sunflower crops and calculate the ratio needed to achieve a 35 percent dry matter (65 percent moisture) blend in the final silage pile.
Adding other dry feeds to sunflower silage can also be an effective means to achieve a 35 percent dry matter final silage blend. Depending on feed availability and nutrient needs of the livestock you intend to feed, consider blending straw, grass hay, grain screenings, or cereal grains with chopped sunflowers to achieve the proper moisture level. As a starting point, 5.5 tons of sunflowers at 25 percent dry matter and one ton of grass hay at 90 percent dry matter would result in a silage dry matter of 35 percent; reducing effluent losses to a manageable point.
Grazing is an option for salvaging a variety of drought-stressed crops, but you will have to consider the availability of proper fencing as well as water supplies for your livestock in the fields you intend to graze. If you are considering renting fields from someone else, be sure you estimate the amount of standing forage available and factor in trampling, waste, and grazing selectivity (the cattle are not going to eat everything in the field) into the amount you pay for rent.
Nitrates will be an issue with drought stressed crops, especially small grains, corn, and sunflowers. The ensiling process will reduce the nitrate content through fermentation but it is important to test drought stressed feeds before you feed them in order to minimize potential nitrate problems.
Water is the most important nutrient for your livestock during drought conditions. This is often overlooked, but performance will suffer greatly if adequate quantity and quality of water is not available.
Summary. Drought-stressed forages can be used in a variety of rations and feeding programs. It is important to get these feeds tested for nutrient content and nitrate level prior to feeding in order to get the most from your feed budget.
Greg Lardy is the head of the NDSU Animal Science department.