Residues of harvested row crops offer considerable low-cost feed if they can be used in a timely and appropriate manner. Timing of use becomes critical in our area since there is frequently little time from completion of harvest until snow flies. The most economical means of utilizing residues is grazing or gleaning.

Sunflower residue feed value is found almost totally in the threshed heads. They contain about 10.5% protein and are highly digestible (nearly 58%) compared to corn and small grain residues. Although the head portion is highly digestible by sheep, no digestive upsets or related problems have been observed from overconsumption of threshed heads.

Residues from grain sorghum are best used by grazing. The stalks can be grazed following snowfall since they remain upright. Composition of dry matter will be around 54% TDN and 5% crude protein.

Soybean and dry bean residues can be used to advantage provided a collection device or machine is pulled behind the combine to collect the finer materials, as they will have the better feed values among residues. Stems themselves, particularly of the soybean, are very low in feed value and ewes should not be forced to consume them.

CAUTIONS!

Many of North Dakota's well-known forages contain potential poisons that normally don't harm livestock. However, under certain conditions these poisons are released in the plant and can cause poisoning if consumed in large enough amounts. Prussic acid is probably the most common.

With frost, sheepmen should use caution when either grazing or feeding sudangrass, forage sorghum, sorghum sudangrass crosses, Johnson grass or flax. The poisoning potential is greatest when grazing forage sorghum and lower with sudangrass and sudangrass hybrids. Beware of grazing flax strips.

Two hard freezes will eliminate most Prussic acid from forage. However, the toxicity potential is very high for the first day or two after freezing, so wait three to five days after a killing frost before allowing livestock to graze. Freezing triggers Prussic acid release, so the forage is very dangerous immediately after a freeze.

Remember these points:
- Mature plants contain less Prussic acid than younger plants.
- There is less acid present in cured hay than in fresh cut hay.
- Wilted forage is especially dangerous.
- New growth following a frost is particularly dangerous.
- Frosted plants that are well dried are safer than freshly frosted material.
- Amount of Prussic acid usually decreases as the plant height increases.

1993