Ammoniation Helps Improve Value of Low-Quality Forages

By Scout Nelson

Livestock producers often face challenges when supplies of good-quality hay are limited or expensive. During these situations, improving the value of lower-quality forage becomes an important management option.

North Dakota State University (NDSU) Extension provides guidance on ammoniation, a process that can improve the feeding value of low-quality hays and crop residues while helping producers make better use of available feed resources.

Ammoniation is most commonly considered when medium- or high-quality roughages are costly or difficult to obtain. Instead of relying only on expensive hay sources, producers can use treated low-quality forage to support livestock nutrition. This approach can help reduce feed costs while maintaining animal performance.

The process works by breaking down the lignin-cellulose bonds found in plant fibers. As these bonds break apart, the forage becomes easier for animals to digest. Improved digestibility allows livestock to consume more forage and use nutrients more efficiently. Specialists report that ammoniation can increase forage intake by approximately 15% to 20%.

“Crude protein can be increased by at least double, and digestibility increased by 10%-30% in crop residues such as straw and corn stalks, making them equivalent to prairie hay in feed value,” said James Rogers, NDSU Extension forage crops production specialist.

Ammoniation also adds nitrogen to the forage. This nitrogen helps feed the rumen microbes that are responsible for digestion in cattle and other ruminants. In addition, ammonia treatment helps prevent forage heating and works as a fungicide when forage moisture levels are as high as 30%.

The practice is best suited for low-quality feed materials. Examples include wheat straw, barley straw, oat straw, corn stover, and mature grass hay. Forages that contain less than 6% crude protein and 48% total digestible nutrients are strong candidates for treatment.

Moisture content is important for successful ammoniation. Forage should contain at least 10% moisture, while moisture levels between 15% and 20% generally provide the best results. Treating immature medium- or high-quality forage usually produces limited benefits and may increase the risk of toxicity problems.

NDSU specialists also provide feeding recommendations for livestock consuming ammoniated forage.

“A balanced mineral and vitamin A should be added to the diet whenever ammoniated residues are fed,” said Vinicius de Souza Izquierdo, NDSU Extension beef cattle specialist.

Research shows that mature cows fed ammoniated residues maintain body weight and condition during most of the gestation period, up to about 50 days before calving. However, certain groups of cattle may need extra nutritional support. These include late-gestation cows, thin cows, growing heifers, and first-calf cows.

Specialists encourage livestock owners to monitor animals closely after introducing ammoniated feed.

“If issues occur, remove cattle from ammoniated forage for several days, and avoid working or exciting them,” said de Souza Izquierdo.

The ammoniation process itself is relatively straightforward. Forage is stacked, covered, and sealed with 6- to 8-millimeter plastic to create an airtight environment. While bale shape is not critical, bale weight is important when calculating the amount of ammonia required.

Anhydrous ammonia is introduced into the sealed stack through a pipe. The recommended rate is 60 pounds of ammonia per ton of dry forage, or approximately 3% of the forage dry matter weight.

“For example, if you are ammoniating 72 bales weighing 1,000 pounds, you would need 2,160 pounds of anhydrous ammonia,” said Karl Hoppe, NDSU Extension livestock systems specialist.

Temperature also affects treatment success. Stacks treated at 86 to 95°F should remain sealed for at least one week. Temperatures of 59 to 85° require one to four weeks, while temperatures below 50° require four to eight weeks. Producers should not treat forage when temperatures exceed 95°F, because excessive ammonia absorption may occur.

Before feeding, one end of the stack should be opened for three to seven days to allow excess ammonia gas to escape safely.

The estimated cost of plastic and anhydrous ammonia ranges from $30 to $40 per ton of forage, not including labor or equipment expenses. Treated forage should also be tested before feeding to evaluate quality and nutritional value. Specialists recommend labeling samples as “ammonia treated” so laboratories can perform the correct analysis.

Safety remains the most important consideration when working with anhydrous ammonia. The chemical is extremely hazardous and requires proper protective equipment, training, and emergency preparation. Because ammonia reacts strongly with moisture, it can cause severe burns to body tissues.

“Because body tissues contain moisture, anhydrous ammonia can damage the eyes, skin, nose, throat and respiratory system on contact,” said Angie Johnson, NDSU Extension farm and ranch safety specialist.

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