To say that the 2015 wheat harvest was and is problematic is an understatement. The rainy weather that delayed harvest has caused some significant quality issues. Grain sprouting, head scab and potential mycotoxin presence have affected the marketability of the grain. There are now reports of mills and co-ops no longer accepting wheat. So, what are the alternatives to the conventional grain marketing channels? What can be done with low quality grain? Based on the questions I have received, it looks like alternative uses include using the grain for cover crop seed and/or using it for livestock feed.
I have been asked if head scab and vomitoxin presence will reduce the viability and germination of wheat if it is used to plant a cover crop this fall. I put this question to Pierce Paul, OSU Extension field crop pathologist and he said he has been getting that question from all over the state so he wrote an article to answer this question. Here is what Pierce has to say:
“Scab will indeed reduce seed quality tremendously, causing germination rates and stands to plummet. However, the vomitoxin that is usually present in scabby seed is not your biggest problem in terms seed germination, damage to the embryo is your problem. You should first pull a grain sample from your lot and determine how badly damaged the kernels are. You can do this by estimating the percentage of Fusarium damage kernels (FDK) - small, shriveled, light-weight, and discolored (pinkish-white) seeds. FDK will give you a very good measure of seed quality.
If you have more than 30-40% FDK, then I would suggest not using your scabby wheat for seed. However, if you absolutely HAVE to plant scabby wheat, cleaning, germ test, and fungicide seed treatment are absolutely necessary. Seed treatment will only help to a point, but you should still treat the seed and try to do so as soon as possible to reduce further fungal growth. If you can increase the test weight to about 56 lb/bu after cleaning and your germination rate is above 80%, then you have decent quality seed. In addition to cleaning and treating, seeds should be stored under cool, dry conditions until planting to prevent mold development. Increasing the seeding rate will also be helpful, but you should determine percent germination first - this will help you to adjust your seeding rate accordingly.”
What about feeding wheat to livestock? Generally wheat is a good livestock feed but there are some additional considerations when feeding scabby wheat, sprouted wheat and/or wheat with mycotoxin presence. Back in 2011, Steve Boyles, OSU Extension beef specialist addressed feeding low quality wheat in an issue of the CORN newsletter. Here are his comments: “Wheat showing more than 2% percent sprouted kernels is classified as sprouted wheat. The nutritional value of grain protein does not appear to be depressed, providing the sprout is not lost. The value of sprouted wheat for ruminant feed is apparently only slightly affected, if at all, by moderate sprouting. One aspect of the feeding of field sprouted grains that must be mentioned is the fact that mold and fungal infestations are more likely with sprouted grain. Care must be taken to avoid feeding moldy wheat to livestock to prevent mycotoxin poisoning. If you suspect toxins, have it tested. The occurrence of scab in wheat does not automatically mean vomitoxin but high levels of scabby kernels in harvested grain should be suspect. If you suspect mold/toxins have it tested.”
There are several different mycotoxins that can develop on scabby wheat, but in the interest of space I am only going to consider deoxynivalenol, commonly known as DON or vomitoxin and the limitation it imposes on animal feed use. The US Food and Drug Administration has set maximum DON levels allowed of 5 ppm for Swine, 10 ppm for ruminating beef and feedlot cattle as well as poultry and 5 ppm for all other animals. In a 2012 University of Minnesota Extension publication entitled “Strategies for Feeding Mycotoxin and Mold Contaminated Grains to Cattle”, the authors review various studies conducted to look at the effects of vomitoxin on sheep and cattle. The review indicated that feedlot cattle and sheep may consume diets containing up to 18 ppm DON dry matter without any adverse effects on health and performance, so the US Food and Drug levels are quite safe. Click on the link above to access the entire document.
With regard to lactating dairy cattle, a very thorough article available on the eXtension web site (http://tiny.cc/dairymycotoxinissues ) indicates that the effect of DON on performance is not as well established but clinical data do show an association between even some relatively low DON levels in the diet and decreased milk production. There are also indications that if DON is present, other mycotoxins may also be present and there can be negative synergistic health effects. DON has been associated with altered rumen fermentation and reduced flow of utilizable protein to the duodenum. Wheat with allowable levels of DON is probably best used with dry cows or growing heifers rather than lactating dairy cows.