Treat forage with ammonia for drought feed option
July 5, 2012
The heat and drought have caused cattle producers to look for methods of adjusting to local conditions. Many who don’t want the expense of additional feeds are considering early weaning and selling replacement heifers. However, an alternative may be ammonia treatment of low-quality forages.
For wheat producers who choose to bale their straw, this provides an opportunity for additional income. But there are drawbacks to removing straw. Many producers leave wheat residue to enhance soil moisture storage for future crops. And some nutrients are also removed in the straw, which can affect future crops.
Irrigated wheat produces considerably more straw; a portion can be removed and still leave some residue. Straw production rates can be predicted fairly accurately if you know grain yield. The Harvest Index (ratio of grain to total dry matter) for most semi-dwarf wheat varieties planted in western Nebraska is about 0.3. A 40-bushel wheat crop will produce about 5,600 pounds, or 2.3 tons, of straw. An 80-bushel wheat crop will produce over 5 tons of straw per acre.
Straw is an ideal source of forage to ammoniate for beef cows. With wheat harvest so early in many areas, some are considering planting hay millets behind straw harvest to produce another (hay) crop to increase income. Crop production budgets for millet and sorghum-sudan crosses following irrigated wheat are currently being developed by Jessica Johnson, Extension Educator in ag economics at the Panhandle Research and Extension Center.
Treatment of low-quality crop residues with anhydrous ammonia improves their digestibility, as shown in the accompanying table. Moisture content of the forage is important. Ideally, best results of ammoniation occur when the forage is greater than 10 percent moisture. Also, ammoniation of forages is successful when the air temperature is over 80 degrees Fahrenheit. Adequate heat has not been a problem of late across most of the High Plains, but waiting until fall is not advised.
Ammoniation is accomplished by covering the straw pile with plastic and applying ammonia to the covered straw. Procedures and how to estimate the amount of anhydrous to apply are listed in UNL Extension Publication EC89-265, which can be found at http://digitalcommons.unl.edu/.
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Presently, anhydrous is selling for $820 per ton, wheat straw is averaging $85 per ton, labor is estimated at $12 per hour and alfalfa hay is estimated at $180 per ton at 18 percent crude protein, 15 percent moisture and 56 percent TDN (59¢ per pound of protein and 19¢ per pound of TDN).
Assuming that 6-8 mil. black plastic sheets are selling for 7¢ per square foot, a 40-foot by 100-foot sheet would cost $280 and plastic pipe would cost $35. Following are some estimates costs to ammoniate a ton of wheat straw:
Equipment (plastic and pipe): $ 9.33
Anhydrous Ammonia: $24.60
Bale wheat straw: $15.82
The cost to ammoniate wheat straw at 89 percent dry matter, 9.7 percent crude protein = 172.66 pounds of protein = 29¢ per pound of protein and 6¢ per pound of TDN.
If cattle producers want to purchase wheat straw at $85 per ton and ammoniate it, their costs would total (without trucking) $134.88, or 78¢ per pound of protein and 16¢ per pound of TDN. Ethanol byproducts or other feeds such as beet pulp and soy hulls can be fed along with wheat straw to meet cow nutrition needs. By evaluating and comparing feed options producers can develop the most cost effective ration to meet livestock needs.