NDSU Extension - Griggs County


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September 14

The Extension Connection

By Megan Vig

                This year’s growing conditions and grain markets are creating opportunities for cheap feeds-- grain screenings and soybeans.  However, proceed with caution if you are looking at turning these into feedstuffs.  This week I share information from Karl Hoppe, NDSU Extension Livestock Systems Specialist on cattle feeds.

                Grain screenings are routinely used as cattle feed.  Since the price of screenings is substantially reduced compared to other feedstuffs, it is an economical feed source for the cattle producer.  The use of this feed source also helps grain farmers avoid discarding or landfilling the screenings.  However, this year’s small grains or small grain screenings may contain ergot.  Some fields have been affected with ergot more or less than others.  There are purchasing elevators that have rejected small grains this season because of ergot levels.  If the elevator has rejected the grain, can one sell it or use it for cattle feed?

                The poison is in the dose and dilution is the answer.   Here is an example:  If the feed was 0.2% ergot by weight, and NDSU’s toxicologist’s recommended maximum for feeding is 0.1% ergot by weight, then limiting this feed at 50% of the ration by weight may not show symptoms of toxicity.  Another example, if the feed was 2.0% ergot by weight, then limiting this feed at 5% of the ration by weight may not show toxicity.  Be careful to obtain a representative feed sample.  If the sample containing ergot was not a representative of a more concentrated portion of the feed, then you will be mistakenly feeding a more toxic ration.   

                Ergot comprises multiple compounds that are persistent vasoconstrictors.  These compounds reduce the blood flow.  Reduced blood flow to the extremities can cause loss of hooves, tails, and ears.  In the summer, cattle cannot dissipate heat and are heat stressed.  In the winter, reduced blood flow to the extremities can lead to frostbite.  Decreased fertility, abortion and poor cattle performance are other symptoms.  Ergot-containing feed can be analyzed for the active ergot compounds.  The NDSU Veterinary Diagnostic Toxicology laboratory can analyze ergot-containing samples for a fee.

                If you are thinking about incorporating whole soybeans into your rations, hold up.  Whole soybeans contain anti-nutrition factors (anti-trypsin and anti-trypsinogen) that require heat treatment to make inactive.  For monogastrics, such as swine, feeding whole soybeans will lead to poor growth.  Heat treatment can be done by extruding or roasting.  Soybean meal is heat treated during the oil extraction process. 

Ruminants, such as cattle, appear to not be affected by same anti-nutrition factors as swine however the high oil content of soybeans limit the use in cattle rations.  In general, when the oil content of the ration exceeds 7 to 9% oil, the oil becomes toxic to the rumen microbes and digestibility of the ration decreases.  Too much oil content in cattle rations will lead to scouring, rumen fermentation can cease, and eventually death. 

While soybeans can be fed to cattle, soybeans can only be fed to cattle at a small portion of the diet.  If the cattle ration is limited on protein, adding soybeans to the ration is a good option for protein supplementation.  At a low rate of supplementation 1 to 4 lbs./head (5-7.5% of ration), soybeans provide added protein and energy (oil).  At this low level of addition, oil isn’t toxic to rumen microbes.  Further, green (harvest early or frost damaged) soybeans can be fed to cattle at low inclusion rates.  A feed test for oil content is recommended if feeding green soybeans.  If you have any questions, contact the Extension Office at 797-3312.

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