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Ammoniation of Dry Forages for Beef Cattle.pdf
Ammoniation of Dry Forages for Beef Cattle
by Dan Faulkner, Extension Specialist, Beef

Research has clearly demonstrated that ammonia treatment of low quality roughages will substantially improve digestibility, voluntary intake and cattle performance. In general, forage crude protein content is roughly doubled, dry matter digestibility is improved 8 to 15 percentage units and intake is increased 15-20% or more by ammonia treatment.

Ammonia improves the digestibility of mature forages by combining with water to form ammonium hydroxide which reacts with the lignin in the plant cell wall to permit better utilization of the complex carbohydrates. Research suggests that hydroxide treatment increased both the rate and extent of cellulose and hemicellulose digestion by breaking the lignin-cellulose bonds, solubilizing the hemicellulose and possibly causing physical swelling of the plant fiber thereby allowing greater microbial activity within the plant tissue. The reaction time for ammonia can be quite long, requiring a minimum of several days, depending upon environmental temperature. Table 1 gives some recommended treatment times according to temperature.

Table 1. Recommended Ammonia (NH3) Treatment Time According to Temperature

Temperature Length of Treatment
Less than 41 degrees Greater than 8 weeks
41 to 59 degrees F 4 to 8 weeks
59 to 86 degrees F 1 to 4 weeks
Greater than 86 degrees F Less than 1 week

We do not recommend treating higher quality hays such as brome, fescue, alfalfa, small grains, forage sorghums or sudans. The high soluble carbohydrate content of such forages when treated with ammonia appears to produce imidazole compounds in some cases. These compounds can produce extreme hyperactivity, convulsions and even death, especially when treated forage makes up most or all of the ration.


  1. Can be applied to any forage package-square or large round bales, loaves, loose stacks, etc.
  2. Forage must be covered with plastic to seal in ammonia:
    1. Group bales or stacks together for efficient plastic use.
      1. Select a level site with wind protection, if possible.
      2. If available, a bunker or pit silo is an excellent site.
    2. Cover with 6-8 mil black or UV resistant clear plastic.
    3. Seal well around edges with dirt, limestone, gravel, etc.
    4. Plastic is not needed under the forage.
    5. Example: 1 roll of 40' x 100' plastic will cover a 5 bale pyramid stack, 15-17 bales long = 84-90 bales.
  3. Apply about 3% (60 lb/ton) ammonia (50 lb actual N) to forage:
    1. Apply ammonia through hose or pipe sealed under plastic.
    2. Use regulator or gauge for accurate application, or order a nurse tank with only the amount of ammonia needed for treatment.
    3. Apply ammonia slowly to minimize ballooning of plastic--1 to 5 minutes per ton has been used successfully.
    4. During application, some of the ammonia will turn to a cold liquid-a depression or trench under the stack will help to contain it.
    5. The gaseous ammonia will balloon the plastic for 1-3+ hours.
    6. Make sure equipment is in good shape, work upwind and handle ammonia safely.
  4. Keep covered for at least 15 to 45 days, depending on temperature:
    1. Best to apply soon after harvest to prevent weathering and field loss-also warm weather speeds up treatment.
    2. Best to leave covered until fed to prevent weathering.
    3. Uncover and aireate 3-7 days prior to feeding to allow residual ammonia to escape.
    4. Can be tub ground before feeding without loss of treatment effect.
    5. If forage is to be analyzed for crude protein, label the sample "ammonia treated" so the lab can analyze it correctly.

Dan B. Faulkner, Extension Specialist / Beef - 217-333-1781
Date: 06/24/1999

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