Yes, drought-stressed sunflowers can be used as a feedstuff for beef cattle. Harvesting as silage or grazing the crop are the most practical and cost-effective means to harvest sunflowers damaged by drought.
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.
Sunflower silage has higher levels of crude protein but lower levels of energy than corn silage. It can be used as a portion of the diet for beef cows and backgrounding calves.
In the past, producers have successfully blended corn and sunflowers together in a silage pile. One load of sunflower silage added to three to four 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.
Sunflowers can accumulate nitrate. Testing the crop for nitrate level prior to feeding is a good idea.
