Category Archives: Forages

Herbicide Grazing Restrictions

Forage Feed Grazing Restrictionscattle in corn stalks

Replant Options Rotation Restrictions-long

Grateful for a nice week for harvesting and for the good yields being reported!  It’s also good to see cattle being turned into cornstalks.  A reminder to read herbicide labels to understand if there’s any grazing restrictions from corn and soybean herbicides applied in-season.

It’s also important to look for any grazing restrictions on fall-applied herbicides to control marestail and other germinating weeds.  These restrictions can also be found in the Forage Feed Grazing Restrictions in the UNL Guide for Weed Management.  The forage, feed, and grazing restriction only applies to the crop for which the herbicide was applied.  When it comes to grazing cover crops planted into these residues, one must use the replant/rotation restriction guidelines found on the herbicide label and in the UNL Weed Guide: Replant Options Rotation Restrictions-long.  I apologize as these scanned blurry; hopefully you can zoom in ok to read what you need.

If the label doesn’t specify any restrictions, then it should be ok. If you want to be on the safe side, a rule of thumb is to use the pre-harvest interval for the amount of time to wait before grazing stalks.  Some labels will say that residue should not be grazed or baled and fed to livestock.  Sometimes studies were actually conducted to know there is a safety concern.  In other cases, the chemical company may not choose to conduct all the studies the Environmental Protection Agency (EPA) required for labeling due to high costs.  If that’s the case, the EPA requires the strongest restrictive language be placed on the label. Regardless, if it says there’s a grazing restriction on the label, the label needs to be followed as it is a legal document and the law.

As you plan for next year’s herbicide program, if you’re thinking about fall cover crops, the following NebGuide may be of benefit to you as it goes through the grazing restrictions of various herbicides.

Cow-Calf College

This looks like an excellent workshop for anyone in cow-calf production.  Hope to see you there!
(Click on the agenda below to enlarge the view).

Cow-Calf College

Feeding Storm Damaged Corn; a Few Thoughts from a Veterinarian

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.  Hail Damaged Corn with fungal growth.

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.

Forage Options After the Storm

Thank you to everyone who participated in the Town Hall Discussion on such short notice last week!  It was cool watchingPanel discussion during storm damage meeting everyone come together to discuss the concerns at hand.  Here’s a recap of some of the discussion regarding forage options.  We also have provided numerous articles this week and will again next week at UNL’s CropWatch website.  I will continue to post more about our local conditions on my blog.

Forage Options

Dr. Bruce Anderson explained that the best potential usage of storm damaged corn that won’t go for grain is to use it for silage.  He stressed that the silage has to be made at the correct moisture and packed well-and that standing corn could be over 80% moisture right now.  He mentioned the easiest and maybe the best way to lower moisture content is to simply wait until some stalks start to turn brown. This will also allow the surviving corn to continue to add tonnage.  If waiting isn’t desirable, 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 with 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 from 80% to 70% moisture.  When making silage, he recommended adding the inoculant during the chopping process to allow for proper fermentation.

He mentioned haying and baling were an option but that he was concerned about the amount of time it would take for the stalks to dry down at the current moisture.  He recommended crimping the stalks if at all possible to help aid in the drying process.  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 them in to reduce the chances of digestive problems.  Also, strip graze the field to reduce trampling losses and get more grazing.

Shredding was mentioned as an option in some fields.  Dr. Bob Klein observed two years ago in the wind storm out in western Nebraska that shredding of plant material led to piles after wind drifted loose material in the field.  That made for a difficult planting situation the following year.  Making earlage was also mentioned as an option.

Additional Resources:

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