Ivan Rush
for Tri-State Livestock News

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September 21, 2012
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Drought and crop residue

It is realized and much is written about drought. It appears that now even if it does rain it won’t help this year’s grass much except for some cool seasons grasses. It will still be absolutely wonderful for fall seeded wheat or fall seeded cool season forage crops such as triticale, turnips, oats, etc. plus it will give some hope to replenish subsoil moisture for next year’s pastures.

It amazes me how often crop residues go unused or underutilized even in drought years. Admittedly, more will be used this year and it is noteworthy that many feedlots that used to feed large quantities of alfalfa are now replacing alfalfa with cornstalks, wheat straw, and other low-quality forages especially when only coarse fiber or roughage is needed in diets such as finishing rations. This has caused an increase in demand for these low-quality forages so more is being harvested and removed from the field. It is especially a good blend with wet feeds such as wet distillers or wet beet pulp.

Even though we see an increase in the use of crop residue we still have a lot that is not utilized. Dr. Terry Klopfenstein, Professor emeritus, University of Nebraska recently calculated that in Nebraska we produce nearly 42 million tons of corn residue and that if all of the approximately two million cows plus one million calves in the state were fed stalks instead of alfalfa that only 2.8 million ton would be utilized. This translates to a mere 6.5 percent of production. Obviously this calculation is for the entire state. There are areas where corn acreage is sparse and cows are plentiful so a much larger percentage is utilized.

There are several reasons for such low utilization: cost of transporting cows, concern over the care taken of cows and the risk of heavy snowfall or other weather events. Plus some worry that subsequent crop yields will be hurt but this is not a valid concern. A famous speaker once said, “Everyone has the right to be ignorant, but not when data shows otherwise.” That’s the way I feel when farmers and crop consultants make this statement when well controlled research data from the University of Nebraska shows otherwise. First of all it is well documented that grazing only removes 10–20 percent of the residue but most of that is returned in the manure. Very little nutrients are removed and if the cattle are supplemented significantly nutrients may actually be added to the soil. Then the excuse is used that cattle pack the ground. Research from University of Nebraska, Lincoln at the Ag Research and Development Center near Mead, NE (where it rains and the soil is heavy) found that when stalks were grazed, the next year’s soybean yields were increased from 60.4 to 62.4 bushels per acre and corn increased from 206 to 209 bushels per acre. Does that tell you that it hurts yields? Other well-controlled research data says the same. Regardless I am sure bias will prevail with some even in drought years when the residues are needed and have value as feed.

Cows gain well on stalks with minimal supplementation and calves will gain very well with protein supplementation plus added energy unless ear drop is significant.

Management is key in grazing corn residue for good performance. Opinions vary on stocking rate for stalks but most agree that unless ear drop is in excess, one should allot 45–60 grazing days per acre. Higher yielding corn offers more residue and higher grazing days. A good observation is that when all of the white husk and many leaves are gone it is time to move. Also keen observation on general cow condition will be important.

It is a commonly-held belief that the genetically modified corn hybrids exhibit reduced stalk quality. Because it is such a strong belief and stated so frequently, to many it has become fact. However I do not know of any data to support this belief and in fact the little data available states just the opposite. It is true that the modern hybrids usually leave less corn in the field than in the past when lodging and ear drop were more common so cows do gain less when less corn is consumed. Some even suggest that the GMO corn has caused genetic modification of the fetus. When asked that question or forwarded the suggestion I usually respond that if they graze stalks they should expect seven legged calves with hair lips.

In general, crop residues offer some real opportunities for some in drought stricken regions. It is not for everyone but many should weigh the opportunity against $250 a ton hay.

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Tri-State Livestock News Updated Sep 14, 2012 01:19PM Published Oct 9, 2012 09:48AM Copyright 2012 Tri-State Livestock News. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.