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.
With corn being harvested for silage, corn maturing early, and livestock producers looking for forage options, I’ve received questions about seeding cover crops or forage options. Mike Burgert from the Clay County Natural Resources Conservation Service also wanted me to share the concern of the loss of reside and the increased likelihood of soil erosion. He said if harvesting crops for forage takes place on a USDA program participant’s “highly erodible” acres, this would likely not be an approved conservation system and could cause ineligibility for USDA programs on all of their land in programs. He also said they have cost share for drought related practices (cover crops for forage on cropland, stock water well/pipe/cross fencing/water facility, etc.).
Dr. Bruce Anderson shared the following information: Before planting anything, review your herbicide history. Prior use of contact herbicides like glyphosate won’t cause any problems, but some herbicides have a long soil residual effect that could prevent successful establishment of some crops. Double crop choice is likely to be different for rainfed and irrigated conditions. One ton (dry weight) of forage production is likely to use 4-5 inches of water. For rainfed conditions, a crop that will winter kill is preferred in order to accumulate soil water from snow melt and spring rainfall for the next crop. For irrigated conditions, forage production will be more with a crop that survives winter and is spring harvested—although irrigation for the forage and following crop will likely need to be increased compared with no double cropping.
Fall Forage options: Determine when the forage crop is to be harvested and how it will be used. For fall-harvested hay or silage, oats or other spring cereals will outyield all other options. Plant about 100 lb. of seed per acre. Various legumes like hairy vetch, field peas, or winter peas can be added to increase protein concentration a percentage point or two, but they are unlikely to increase dry matter yield; the forage from the cereal alone will meet most cattle protein needs. Also be wary of spending more for the seed than the extra protein might be worth. For grazing this fall and winter, turnips and oats (separately or in a mixture) usually will provide the most feed.
Early planting and emergence (irrigation or soil moisture must be available immediately) is essential for successful fall forage. Plantings after Labor Day rarely produce sufficient growth for mechanical harvest in the fall and the amount of fall grazing becomes negligible for plantings made after mid-September. Even earlier planting dates may be needed for sites north of the Platte River. Later plantings should consist of winter cereals. Also, the chances for successful establishment are low unless soil is sufficiently moist to at least an eight-inch depth at time of planting.
Spring Forage Options: For spring forage, the winter cereals rye, triticale, and wheat tend to be the best choices. Rye is your best choice for early spring pasture and produces much growth before being terminated for timely planting of a row crop. Some rye varieties also provide enough fall growth for some light grazing if planted early enough. Rye also may be the most reliable crop when planted under stressful conditions. Rye has some drawbacks. It turns stemmy and matures much earlier than triticale or wheat, with a loss in feed value and palatability, although this should not be an issue if harvest ends in time for spring planting of a row crop. Also, it should not be used in fields that will be used to grow grain wheat due to potential contamination that could lead to discounts/dockage when wheat grain is sold.
Triticale holds on to its feed value best into late spring. This makes it well suited for hay and silage, or for stretching grazing well into June if grazing begins two or three weeks later than it could begin with rye. Triticale often is more susceptible to winter injury than rye and wheat.
Winter wheat will provide very little grazing for fall. During spring, forage quality and acceptance is very high but forage yield is less than rye and triticale. It can be grazed and then allowed to produce grain if grazing ends when plants begin to joint and elongate.
Mixtures often can be desirable and can be designed for individual needs. For example, an early planting of 30 lb. of oats plus 75 lb. of winter rye per acre may provide both fall grazing from the oats and spring grazing from the rye.