This past year has seen tough growing seasons across the US. The high plains suffered drought and wildfires, the Midwest and Northeast had rain that delayed planting and first crop harvest. Recently, the Southeast was hit with rain from Harvey and other storms that have caused severe damage in Florida and up the coast. In past newsletters, we have focused on forage quality and quantity due to delayed planting and a wet, cool growing season. The following is an excerpt from a previously written factsheet by Janet Fallon in 2014.
In general, affected fields may have a lot of debris and dirt on them. This places them at greater risk for fungal and bacterial contamination that may have a negative impact on fermentation and feed quality. It may also cause dusty, dirty harvest conditions that may result in added costs from wear on machinery. If corn plants have a lot of silt on them, grain harvest may be a better choice since corn for silage will be at greater risk for fungal and bacterial contamination.
The following guidelines may help reduce risk on damaged fields chopped as silage.
- Scout fields before harvest to identify potential problem areas and schedule harvest.
a. Check whole plant moisture, kernel development, and presence or absence of any ear or stalk rot.
2. Tighten up management at harvest to promote a good fermentation.
a. Chop at the right length of cut.
b. Use an appropriate inoculant.
c. Fill fast, pack well, cover tightly.
3. Harvest above the silt line to avoid soil contamination.
4. Avoid chopping fields with heavy dirt or silt on it.
5. Keep flooded forage separate so it can be evaluated before feedings. Testing for energy, ash and mycotoxins is highly recommended.
6. Monitor animal health closely. Contamination from manure, sewage, and other chemicals is possible.
Harvesting flood damaged corn for grain should be carefully managed as well;
1. Monitor the field prior to harvest. Look for stalk and ear rots that may indicate an elevated potential for mycotoxins in the harvested grain. Fields that remained flooded for more than 12 hours are at greatest risk.
2. Change combine air filters more frequently, and operators should avoid breathing too much dust.
3. Limit dirt coming into the grain bin by harvesting grain as dry as possible and avoiding the hardest hit areas in fields.
4. Monitor grain quality. Mold and mycotoxin levels may be higher in damaged or stressed con fields and should be tested.
Once things have dried out enough for harvesting perennial forages, check the field for a few things:
1. Remove any debris that may damage farm machinery or harm animals. It is amazing what you might find in your fields after a flood!
2. If it is time to harvest the forage but it is covered in silt and sediment, it may be best to simply mow and chop the forage right back on the field, top-dress it to stimulate regrowth and move on. The risk due to pathogens, limited palatability and poor fermentation is just too great. Of course, wait until your crop insurance adjuster has had a chance to see it first!
3. If several weeks will elapse before harvest, wind, rain, and sunlight will help remove sediment and kill off some of the potentially harmful bacteria that may limit fermentation. Proceed as usual but keep forage separate from non-flooded forages if possible. Ag bags or separate storage areas will allow you to sample, evaluate and adjust rations accordingly.
4. Follow best management practices-monitor harvest moisture, length of cut, fill fast, pack well, use an appropriate inoculant to make sure you have the right bacteria for the job and seal the silo to keep oxygen out.
5. Test all forages as usual but keep a close eye on the VFA score and ash content.
6. Top-dress fields that appear to be in good condition. At least 4 healthy alfalfa plants per square foot are needed to justify additional inputs of fertilizer and herbicides.
In summary, practice extreme caution when harvesting and feeding flood damaged forages and grains. We recommend keeping all flood damaged feeds separate from undamaged feeds and test for feed value and toxins to avoid animal health and production problems down the road. Our (321) Forage NIR package is probably your best bet to quickly and accurately test the feed value. It also provides a VFA score for your ensiled feeds. Mycotoxin testing is another recommended procedure for flood damaged feeds.