Cooperative Extension Service
The University of Georgia College of Agricultural and Environmental Sciences
PDF

	Ammoniation of Hay
	Robert L. Stewart and Ronnie Silcox Extension Animal Scientists

Many of the forages fed to beef cattle in the Southeast are traditionally low in crude protein and energy when harvested. Examples are low-quality grass hay, crop residues and endophyte-infected fescue hay. Cattle can use these forages, but performance may be limited by low digestibility and reduced consumption. These forages usually require supplemental protein and energy in order to feed a balanced ration.

The large supply of these low-quality roughages has prompted research on chemically treating hay to improve quality. The most promising method is to treat the hay with anhydrous ammonia. Studies have shown that quality can be improved at a reasonable cost when anhydrous ammonia is properly applied to low-quality forage.

Proper handling of anhydrous ammonia is extremely important. This chemical is very caustic and will cause injury when it comes in contact with skin. Please observe all safety rules when ammoniating hay.

Crops to Use

Scientists have conducted extensive research on the effects of ammonia treatment on a wide variety of forages. The forages that show the most promise are low-quality grass hay and straw from cereal grain and wheat. Consider using these listed below in your feeding program, since many are available to Georgia cattle producers.

Low-Quality Grass Hay -- Probably the largest tonnage of any forage harvested for winter feed is low-quality grass hay. Grass that is poorly fertilized, poorly managed and cut at a late stage of maturity will be deficient in protein and energy. Such low-quality hay is an excellent candidate for ammoniation. Crude protein can be improved by 6 to 8 percentage units and total digestible nutrients (TDN) can be improved by 8 to 12 percentage units. In most cases, ammoniation can eliminate the need for supplemental protein and energy for lactating cows.

Crop Residues -- The residue (or straw) from grain crops responds especially well to ammoniation. Corn stalks, cereal grain straw and wheat straw have proven to be good-quality forages when ammoniated. Crude protein has been raised by 5 to 8 percentage units and TDN has been improved by up to 20 percentage units. Other crop residues, such as peanut hay and soybean stubble, have not proven to be well suited to ammoniation.

Fungus-Infected Fescue -- In recent years, an endophyte fungus was discovered in most of the Kentucky 31 fescue that has been established in Georgia. When present in large quantities as grazing or hay, this fungus reduces daily gain, milk production and conception rate of cattle. If properly ammoniated, however, the fungus will no longer be harmful. Improvement in animal performance is therefore above that expected from increased hay quality resulting from ammoniation. Any cattle producers who know of or suspect fungus infection should consider the advantages of ammoniating their fescue hay.

High Quality Forages -- Well-managed, high-quality hay crops of any type should not be ammoniated. A condition referred to as "bovine hysteria" has been associated with excellent quality hay that has been treated with ammonia. This condition has caused adult cows to temporarily go crazy. In some instances, the death of young suckling calves has resulted.

Effects of Ammoniation

Mature hay and crop residues are low in digestibility because of their high fiber content. Such forages have a higher percentage of stems and lower percentage of leaves as compared with forage cut at earlier stages of maturity. The stems (or stalks) contain a high concentration of lignin, which is highly digestible. In addition, lignin bonds to other carbohydrates in the plant, which further reduces the feeding value of these forages.

Treatment with anhydrous ammonia helps break the lignin bonds and so increases the digestibility of these low-quality forages. In other words, ammoniation "pre-conditions" the forage, making it more available for the rumen bacteria to convert into usable energy. The ammonia will bind to the forage and serve as a source of non-protein nitrogen. The rumen microbes can convert the ammonia into crude protein. Therefore, ammoniation improves forage quality by increasing both energy (digestible fiber) and crude protein. Table 1 shows the effect of ammoniation on several crops.

Table 2 illustrates the effect of ammoniation on animal performance. In this example, the treated forage resulted in higher daily weight gain and increased hay consumption. Especially noteworthy was the benefit when feeding fungus-infected fescue hay. The improvement in daily weight gain was above and beyond that expected due to the increase in energy and protein from ammoniation.

Ammonia reacts with the fiber in hay more quickly under hot temperatures. Therefore, it is best to ammoniate hay during the summer or early fall. The natural heating from direct sun will aid the ammoniation process.

Materials and Equipment Needed

Before actually treating the hay, make a checklist of all the materials needed. Have them ready to use so you will not need to stop in the middle of the ammoniation process.

Anhydrous ammonia -- You will need to buy anhydrous ammonia from a fertilizer dealer in your area. The ammonia will be in a pressurized nurse tank that you haul to your farm. Check local sources to make sure it is available.

Regulator -- You will need a field-type regulator in order to deliver the ammonia at the desired rate of approximately 10 pounds per minute. It should have a safety valve attached to a rope for emergency shut-off in case of an accident. You will also need appropriate fittings and a high-pressure hose in order to deliver ammonia from the nurse tank to the regulator. These may be available from the same source as the ammonia.

Manifold -- You will need a manifold to connect to the regulator if you want to apply ammonia in several locations in the stack at the same time. The manifold connects to the regulator and simply splits the ammonia flow into two or more directions.

Hoses -- Have hose of the appropriate diameter (to fit the regulator or manifold) and length (to reach the stack of hay to be treated). A high-pressure hose is not required because of the low flow rate of ammonia. Be sure, however, to use a material that is resistant to the corrosive action of anhydrous ammonia. You may also need short pieces of non-galvanized metal tubing (same diameter as inside of hose) to serve as a probe in order to pierce the plastic that surrounds the hay.

Plastic -- Buy high-quality 6 mil black plastic in large sheets to seal the hay.

Tape -- You should have on hand a roll of pliable plastic tape. This is used to seal any holes in the plastic and to reinforce spots where the plastic will be pierced by the probe.

Figure 1. Hay being ammoniated using a nurse tank, regulator, tubing and probes.

Amount of Ammonia to Use

According to current research, the optimum amount of ammonia to use is 3 percent (by weight). To calculate the amount needed, simply estimate the weight of hay and multiply by .03. Example: You have 40 bales weighing approximately 950 pounds per bale.

You should add 1,140 lbs. of anhydrous ammonia.

Take care when measuring the amount of ammonia delivered. Since it is usually not practical to have scales present, you will have to estimate the amount of ammonia to use. There are two methods you can use to assure accuracy:

Tank gauge -- The nurse tank will have a gauge that measures the ammonia as a percentage of the tank capacity. A 1000-gallon tank with a gauge that reads 60 percent would contain 600 gallons. A gallon of ammonia weights approximately 5 pounds. To deliver 1,140 pounds of ammonia (from example above), you would calculate:

Gallons of ammonia = 1140 ÷ 5 = 228 gallons
% of 1000-gallon tank = (228 ÷ 1000) 100 = 22.8%
Final Tank Reading = 60 - 22.8 = 37.2%

If the gauge on the tank reads 60 percent to start with, then deliver ammonia until the gauge reads approximately 37 percent. Note: Be sure that the nurse tank is on level ground. The gauge will not register accurately unless the tank is level.

Flow rate -- The flow rate setting on the regulator will help you determine the amount of ammonia. If the flow rate is set at 10 pounds per minute, then it will take 114 minutes to deliver 1,140 pounds of ammonia.

Weigh the tank at the fertilizer dealer's before and after ammoniating the hay to serve as a check on the amount you actually used. Try to accurately deliver 3 percent of the weight of hay. There is no advantage using higher amounts. Lower amounts will not completely ammoniate the hay.

How to Ammoniate

There are several methods of ammoniating hay successfully. All methods have the following basics in common: (1) cover hay with plastic and seal off leaks; (2) apply anhydrous ammonia at the rate of 3 percent by weight; (3) allow four to five weeks reaction time; (4) uncover bales as needed to feed.

The most common method of ammoniating hay is the stack method. The proper steps are --

• Stack the hay. The stack can consist of square bales or large, round bales. The size of the stack depends on the size of the piece of plastic that covers it. For best results, allow space at the ends and/or middle of the stack for 55-gallon drums. Plow dirt back around the edges.
• Cover the stack with plastic. Run the hose from the regulator under the plastic and into the 55-gallon drum. Seal the edges of the plastic with dirt by turning the loose dirt (that was previously plowed) back onto the edges.
• Turn the ammonia on at the nurse tank. Slowly increase flow rate at the regulator up to approximately 20 pounds per minute. The 55-gallon drums will act as a reservoir for the ammonia that comes out in liquid form. The liquid ammonia will slowly evaporate into gas and percolate throughout the stack of hay.
• Check for leaks and seal with tape.
• Seal the stack. After the proper amount of ammonia has been added, turn off the nurse tank, remove the hose, and seal the hole with dirt.
• Allow to "cook" for four to five weeks.

Figure 2. A sheet of plastic covers the bales of hay and is sealed with dirt around the edges.

Economics of Ammoniation

Before deciding to ammoniate a forage, consider the costs and benefits. Costs can be itemized into the following categories:

Ammonia -- Calculate the cost of 60 pounds of ammonia. At $200 per ton for ammonia, 60 pounds would add $6 to the cost of a ton of hay.

Plastic -- The price of plastic will vary, but a good estimate would be $5 to $8 per ton of hay.

Other -- Consider other costs such as extra hauling, equipment and labor. An estimate of $2 per ton should cover these expenses. In this example, you may spend up to $16 per ton of hay for ammoniation.

Can you justify these costs? Consider the three benefits that follow.

• Increased quality - You add considerable value to a ton of hay when protein content is improved by 7 percentage units and TDN is improved by 8 (or more). One way to estimate this value is to compare ammoniated hay with other feeds. When corn costs $2.50 per bushel and soybean meal costs $200 per ton, the improved nutrient content of ammoniated hay is worth $25 or more per ton.
• Less spoilage - Cover the hay with plastic to reduce spoilage from rain and weather by 10 to 30 percent. When compared with outside storage, the savings you get by avoiding spoilage will offset much of the cost of ammoniation.
• Increased palatability - Ammoniation greatly increases palatability of low-quality forages. Research indicates a 10- to 25-percent increase in consumption when forages are ammoniated. Cattle consume more of the hay, which results in less waste when feeding.

Feeding Recommendations

Ammoniated hay or straw can be the primary forage in a winter feeding program. Although quality is improved by ammoniation, ammoniated forage may be deficient in some nutrients. The most likely nutrients to be deficient include --

Energy -- Rations for lactating brood cows and growing animals may require some grain supplementation.

Minerals -- You should always offer a free-choice salt/mineral mix containing calcium and phosphorus. Straw from wheat and cereal grains is likely to be deficient in magnesium. When feeding these residues, offer a mineral mix fortified with magnesium (a grass tetany mineral).

Vitamin A -- If lush grazing is not available, then be sure to supplement the ration with vitamin A. This can be done by adding 25,000 units per head to the grain supplement or feeding a mineral mix fortified with 140,000 unit per pound of mineral.

For best results, have the forage tested before and after ammoniation. Indicate on the sample identification form that the forage was (or will be) ammoniated.

Keep the stack of hay covered until shortly before feeding. When exposed to rain and weather, ammoniated hay will spoil very quickly. Most cattle producers allow the ammoniated hay to "air out" for a day before feeding. Many producers, however, have been successful feeding ammoniated hay directly from under the plastic.

Use hay rings when feeding the hay. Losses due to trampling are greater unless the hay is fed in rings.

Safety

Anhydrous ammonia is a dangerous chemical. Exposure to skin, eyes and lungs can cause serious injury. Use goggles and rubber gloves to protect your eyes and skin when connecting ammonia hoses and turning valves. Anyone working around anhydrous ammonia hoses should have a small bottle of water in his/her pocket. The word anhydrous means "without water." If it gets on your skin or in your eyes, it will disrupt cell structure. The personal bottle of water will allow you to immediately get water to the affected area of your body and give you time to get to the nurse tank, which should have a 5-gallon container of fresh water on it. Flush the affected area with water for at least 15 minutes. If a tragic accident (like a hose break) occurs, your clothing will actually freeze to your skin. In this case, hose yourself down or get into a stock tank, pond or any other readily available source of water to thaw the clothing before removing it.

Please use extreme care. An unfortunate injury from anhydrous ammonia will nullify any of the benefits you may have received from an increase in forage quality.

Summary

Treating low-quality forages with anhydrous ammonia is a valuable technique for Georgia cattle producers. Using low-quality grass hay and crop residues will help keep the annual costs of cattle production low. The improvements in quality and palatability more than offset the cost of ammoniation. The major benefit is that low-quality roughage that are of little or no value as feed can be transformed into good-quality forages when properly ammoniated. Handle anhydrous ammonia with respect. Observe all safety guidelines and always use care.

Leaflet 402/Revised June, 2001

The University of Georgia and Ft. Valley State University, the U.S. Department of Agriculture and counties of the state cooperating. The Cooperative Extension Service, the University of Georgia College of Agricultural and Environmental Sciences offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or disability.

An Equal Opportunity Employer/Affirmative Action Organization Committed to a Diverse Work Force

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, The University of Georgia College of Agricultural and Environmental Sciences and the U.S. Department of Agriculture cooperating.

Gale A. Buchanan, Dean and Director