Sometimes finding a new use for a feedstuff can be more valuable than adding a new forage to your program. Take, for example, chaff and straw. In the eyes of many beef producers, they offer little feed value.
That image can be changed by ammoniating low-quality forages, says North Dakota State University (NDSU) Extension beef specialist Greg Lardy.
Treating cornstalks and small grain straw with anhydrous ammonia breaks down the linkages between fibers, increasing digestibility 10-30%and boosting consumption of those feeds by 15-20%. It can also double or triple crude protein levels and make those crop residues equivalent to prairie hay in feed value, according to Lardy.
Improving the nutritive value to that extent could help some producers cut the cost of buying additional hay, says Norwood Van Dyke, Extension animal scientist at Auburn University.
"As long as the price of ammonia is reasonable, ammoniating forages can be cost-effective," says Lardy. The cost of ammoniation ranges between $24-35/ton of dry matter, with wheat straw estimated at $18/ton, plastic at $5/ton and anhydrous ammonia at $9/ton.
While those numbers make straw and chaff sound more appealing, "it's still not used enough," says Van Dyke.
Van Dyke says that is in part due to some of the hazards involved in using anhydrous ammonia and the work involved, but also because producers simply don't know much about ammoniating forages.
When Ammoniation Works Best Lardy says ammoniation works best on low-quality forages including wheat, barley and oat straws, corn stover and very mature, low-quality grass hay.
"We've seen quite a bit of ammoniation of forages used in Canada, especially of chaff. One producer put the chaff in a pile, ammoniated it and then put an electric fence around it to let the cows self-feed on it," says Lardy.
However, ammoniating forages above 6% protein isn't recommended, Lardy says. Medium- to high-quality forages treated with anhydrous ammonia results in only small changes in digestibility and intake and may cause toxicity problems when fed, he adds.
In a forage program, Van Dyke says ammoniated forages are well suited as feed for cows with the lowest protein requirements, such as dry cows in the winter.
But gestating cows can utilize the feed as well. Cows fed ammoniated residues will maintain weight and condition during gestation until 50 days prior to calving, Lardy says (see Table 1). However, he cautions that ammoniated residues may not work well if cows are in thin condition.
Phosphorus, trace minerals and vitamin A should be supplemented whenever ammoniated residues are fed, Lardy adds. For gestating cows, additional supplementation will be required immediately prior to calving and during lactation.
Step By Step While ammoniating crop residues requires some time and effort to stack and cover the bales, it's relatively easy, says Lardy.
However, caution should be taken when working with anhydrous ammonia. Misused, it can burn skin, eyes or throat or even explode and burn.
* Forage stacks must be covered and sealed with plastic to make an airtight environment. Six to eight millimeter black plastic is recommended.
Bales should be stacked in a pyramid with about 2 in. between bales to allow for maximum exposure to the ammonia.
If possible, stacks should be located in an area with protection from strong winds and good drainage. Lardy suggests disking the area to loosen the top few inches of soil for anchoring the plastic.
* Once the pile is covered, leave a small space to insert a pipe for adding anhydrous at the midpoint of the stack.
Insert a pipe 6-10 ft. long on the ground and seal plastic with loose soil around the pipe. Connect the pipe to the anhydrous tank hose with an adapter. Use a shut-off valve on the pipe to eliminate back flow of anhydrous when disconnecting.
* Add 60 lbs. of anhydrous ammonia per ton of dry forage (3% dry matter content). Best results are achieved when the forage has greater than 10% moisture, with 15-20% being ideal. To ensure moisture in the forages, bale the forage shortly after harvest, or in early morning or late evening when there is dew on the forage. Molds won't grow on ammoniated forages because ammonia is a fungicide.
Total time for addition of the anhydrous will be 8-10 minutes/ton of residue; a 30-ton stack requires about five hours.
* After treatment is complete, turn off the valve, remove the pipe and seal the area where the pipe was removed. The forage will need to be sealed for one to eight weeks depending on temperature (see Table 2). The cooler the temperature, the longer the residue needs to remain sealed.
Open one end of the stack three to five days prior to feeding to let the excess ammonia dissipate.
For more information contact your local Extension agent.