Much to Consider When Feeding Drought-Stressed
Soybeans, Sorghum
Feeding drought-stricken soybeans or sorghum as forage requires close
management. While they're good sources of needed livestock feed, they
also can be toxic, University of Nebraska specialists said.
When used right, the drought-stricken forages are a good substitute
for dry pastures, said Bruce Anderson, forage specialist in NU's Institute
of Agriculture and Natural Resources.
Harvesting and feeding soybean hay or silage is similar to feeding
alfalfa, he said. Harvesting sorghum for forage is similar to harvesting
corn and it also can be made into hay or silage.
Feeding these drought-stressed crops is much like feeding other hay
crops. Beef, dairy cows and sheep can use the fibrous nature of these
drought-damaged plants, while swine can use it more as a filler, Anderson
said.
Livestock can graze soybeans, but usually shouldn't graze sorghum
because it is too high in prussic acid and nitrates, which are poisonous
to cattle, Anderson said.
Soybean silage is best made with a moisture content between 60 percent
and 70 percent, Anderson said.
A useful in-field method to test silage moisture is the squeeze test.
After chopping some forage, grab a couple of handfuls and squeeze
it tightly for about 30 seconds. If it stays in a ball and the palm
of the hand is moist, but not dripping wet, it's just right for chopping.
Forage quality drops quickly in soybeans after seed begins to form.
It should be harvested before the bottom leaves start to turn yellow,
and cut earlier if possible because the stems become woody and poor
in quality.
It's especially important to harvest before a freeze to prevent leaf
loss, Anderson said.
"With soybeans we also have to avoid the loss of leaves,"
he said.
"They crumble easily. We just can't cut them when they start
drying, or we'll get sticks."
To aid fermentation in chopped soybean silage, it may be best to mix
in chopped soybean plants with corn or sorghum silage, Anderson said.
A ration of 1 ton soybean silage to 3 or 4 tons of corn or sorghum
silage will improve fermentation of the soybean silage and increase
protein content of the corn or sorghum silage by 2 to 3 points. ©
