With the recent sprouting of grain on the ears and with more producers now learning what percent loss their crop insurance is determining for each field, I felt it would be good to talk about feeding this damaged grain again. This post is written by Dr. Dee Griffin, DVM at UNL’s Great Plains Veterinary Education Center at Clay Center. I appreciate Dee’s willingness to provide this information from a Veterinarian’s perspective.
Also a note, to date we have not found Aspergillus in our hail damaged fields. The grain molds we are seeing are Diplodia and Fusarium. Diplodia does not have the potential to produce mycotoxins. Fusarium has the potential of producing fumonisin, vomitoxin, or DON. You can bring forage samples to Husker Harvest Days this coming week to the IANR building and have them tested that day for nitrates for free if you wish.
Dr. Griffin writes: Any time a growing grain producing plant is damaged there is a potential for changes in the plant or grain on the plant contaminated with fungus/molds to grow. The most common change in stressed plants is the accumulation of nitrates. Aspergillus or Fusarium will be the most likely fungi to be contaminating harvested grain from storm damaged corn in our area.
It is really important to know that most molds are not toxic. Therefore just because mold growth is observed doesn’t mean the feedstuff will harm livestock. Even though a mold may not be toxic it can still cause feed refusal. Not all livestock species are equally sensitive to mold contamination and not all production groups are equally sensitive. For instance pregnant and young animals are more sensitive than mature non-pregnant animals.
Nitrate accumulation in stressed plants can cause be harmless or cause serious harm depending on:
- the level of nitrate in the feed harvested from stressed plants,
- on the life stage of the animal,
- and on the species of animal.
Nitrates accumulate in the forage portion of the plant, so nitrates are not a concern in grain harvested from stressed plants. Additionally, it is important to know nitrate levels will always be highest in the bottom part of the plant and lowest in the top foliage. Nitrate testing is simple and reasonable quick. Your local UNL Extension Educator can help you locate the nearest facility that does forage nitrate testing.
Feed containing nitrate levels less than (<) 1000 parts per million (ppm) seldom are associated with an animal health concern. Feed containing nitrate levels greater than (>) 1000 ppm may be a concern in younger animals and levels >2000 ppm should not be fed to pregnant cattle. Feeder cattle are reasonably resistant to nitrates but feeds containing >4000 ppm should not be fed to any animals.
Molds in corn grain of concern could be either Aspergillus or Fusarium. Your UNL Extension Educator can be a great help in identifying mold growing on ears of your storm damaged corn before the grain is harvested. Both of these fungi are potentially dangerous when found in livestock feed. Toxins produced by molds are extremely stable, therefore if a significant level is found, the level will not decrease over time. Silage produced from damaged plants and grain harvested from mold infested plants is potentially a problem.
Good silage management is critical to lessen the likely hood of continued mold growth after ensiling. Proper packing to remove oxygen and improve fermentation which ensures the pH will be below 4.5 is critical.
You can’t look at harvested grains from storm damaged fields and visually identify mycotoxins. Corn grain from storm damaged fields can … and mostly likely should … be tested for mycotoxins before feeding to livestock. Your local UNL Extension Educator, nutritionist or veterinarian can help with mycotoxin testing.
Proper sampling is crucial to getting reliable results back from the laboratory. A “grab sample” is not adequate. The sample submitted to the lab should be representative of the entire load, bin, pit or pile of feedstuff being evaluated.
The steps are simple
- If sampling a field before harvest, sample at least two dozen ears that appear to have mold growth and submit all the ears to the laboratory for mycotoxin evaluation
- If sampling after harvest, take multiple samples uniformly from throughout the silage or grain in question
- The sample should be taken from what would be used in a single load of feed
- That means, if five loads of feed could be made from a 50,000 lb semi-load of corn, collect not less than five samples from the semi-load of corn
- The sample should be based on sample volume not weight
- For instance, collect “coffee can” size samples
- Mix all the all samples together that were collected from the feed in question
- For instance, if 10 coffee can size samples were collected from across the face of a silage pit, pour all 10 samples onto a plastic sheet and thoroughly mix them together
- Next, collect a single sample from within the 10 mixed samples
- Submit the single sample to the laboratory
The laboratory results usually will provide some recommendations for how the feedstuff can be used. There is an old saying, “Dilution is the solution …” meaning in this consideration, that many feedstuffs that contain higher levels of mycotoxin than would be acceptable, might be usable if a sufficient amount of non-mycotoxin contaminated feedstuff is used to dilute the mycotoxin. Your UNL Extension Educator, nutritionist or veterinarian can help evaluate the possible uses of a damaged feedstuff containing unacceptable levels of a mycotoxin.
The rain was welcome on Thursday but the wind and hail damage that came were devastating to a good portion of the County. I’m so sorry to all of you affected….for some of you, this is two years in a row of severely hail damaged or totaled out crops. We are thankful the damage wasn’t worse. You can see more pictures here.
So the big question is what do you do now? Ultimately, each field will need to be assessed on a case by case basis. The following are our NebGuides for hail damage to corn and soybeans. For the most part we were in brown-silk to blister for corn and late pod-beginning seed in soybean (R4-R5). The concerns I have right now are stalk quality, disease, grain filling, and the amount of diseased grain we may have due to mushy areas on hail-damaged cobs right now. Several years ago, we watched how severely hail-damaged corn a little later in the season turned brown and died. We also know that southern rust is in the area and while much of the leaf tissue in the County is damaged, it is still in the County in other fields and south of us. The Puccinia polysora fungus that causes southern rust, when severe enough, will infect and cause pustules on the stalks. With the wounding and low leaf area for photosynthesis, stalk strength is a concern and fungicides may be a consideration depending on potential yield loss-again need to assess on a field by field basis.
I talked with a number of people on Friday regarding thoughts on silage, green chop, haying/baling, planting cover crops, etc. Dr. Bruce Anderson, UNL Extension Forage Specialist, said the most common salvage operation for corn damaged by hail, wind, drought, or other calamities is to chop it for silage. Don’t be in a hurry, though. Standing corn currently could be over 80 percent moisture. The easiest way, and maybe the best way, to lower moisture content is simply wait until some stalks start to turn brown. Waiting also allows surviving corn to continue to add tonnage.
But in some of our damaged fields, I don’t think we can wait to make silage. Bruce also shared you can reduce moisture by windowing the crop and allow it to wilt one-half to one full day before chopping. You also could mix grain or chopped hay to freshly chopped corn to lower the moisture content. It takes quite a bit of material for mixing though – about 7 bushels of grain or 350 pounds of hay to lower each ton of silage down to 70 percent moisture from an original 80 percent moisture. That’s 7 bushels grain or 350 pounds of hay for each ton of silage.
Or, you can allow that windrowed corn to dry completely and bale it as hay. Be sure to test it for nitrates before feeding. Grazing might be the easiest way to use damaged corn, and this is a good way to extend your grazing season. You might even plant some corn grain or sorghum-sudangrass or oats and turnips between rows to grow more forage for grazing if you can wait until late fall before grazing. Be sure to introduce livestock slowly to this new forage by feeding them before turning in to reduce the chances of digestive problems. Also, strip graze the field to reduce trampling losses and get more grazing from the corn.
Unfortunately the drought continues to intensify. All Nebraska counties have now been released for haying and grazing of Conservation Reserve Program (CRP) lands. Information and resources continue to be added to UNL Extension’s Drought Resource page at http://droughtresources.unl.edu. Please check it out for drought information for livestock, crops, water, and gardening.
Some have started chopping corn for silage or are about to soon. Dr. Bruce Anderson, UNL Extension Forage Specialist, shares the following information about maintaining silage quality in the future. “After silage has been chopped and piled and packed correctly, it still can be damaged seriously by air and moisture slowly penetrating the outer 3 to 4 feet. Animals often eat less when fed moldy silage and can even experience health problems due to mycotoxins.
Good, well-eared silage can lose over 20% percent of its feed value from fermentation and spoilage under normal conditions. Silage made from corn with little or no grain might have even greater losses. This loss can be cut in half or even more if the silage is kept well covered by plastic.
Cover freshly chopped silage with black plastic immediately after you finish filling the trench, bunker, or pile. Then cover the plastic with something to help hold it down. Old tires are readily available and do a good job of keeping the plastic from blowing away, but they only keep keep pressure on the silage directly under the tire. In between the tires, air can circulate and cause spoilage.
An even better choice would be a solid cover over the plastic, something like freshly chopped forage or weeds or maybe even a 3- to 4-inch layer of manure. This would ensure that the entire surface of silage is fully protected to reduce the chance for air bubbles to form under the plastic which could reduce silage quality. You go to a lot of time and expense to make good silage. Isn’t it worth it to protect that investment?”