Livestock producers who need more forage might consider a late planting of sunflowers, says Bruce Anderson, University of Nebraska Extension forage specialist. They may be your best bet for replanting a field or double cropping after wheat, says Anderson.
He points out that sunflowers are relatively drought resistant and safe from most common insects and they tolerate most soybean herbicides. When chopped for silage and fed as a full feed to steers, they can support nearly the same rate of gain as alfalfa haylage. In a mixed ration, alfalfa will be more valuable as a protein supplement, but sunflower silage will have about the same value as forage sorghum silage. For dairy cows, sunflower silage has about 70-80% of the feeding value of corn silage.
In Nebraska, sunflowers can be planted for silage as late as July, says Anderson. Oilseed types are best when planted at 20,000-30,000 seeds per acre.
Harvest sunflower silage when 50-65% of the plants are blooming. If harvests occurs before frost kills and starts to dry up the plants, wilting or adding a dry feed may be needed to get moisture content down to near 65%. Use a silage inoculant and add about a bushel of grain per ton of silage when filling to improve fermentation and feeding value of the silage.
The silage should contain around 11-12% protein and 60% TDN. “Yield will increase if you harvest later, but the silage will be less palatable due to more coarseness of the stems,” says Anderson.