The effects of ammonia volatilization from litter can be significant at levels above 25 parts per million. It may adversely affect the birds’ growth rate, feed efficiency, and egg production; damage the respiratory track; and increase the birds’ susceptibility to a variety of avian diseases, including Newcastle disease, airsaculitis, Mycoplasma gallisepticum, and keratoconjunctivitis.
Ammonia volatilization from litter also contributes to acid rain. In Europe livestock wastes are considered the dominant source of ammonia pollution in acid rain, and emissions increased as much as 50 percent in the three decades leading to 1980.
Methods to reduce ammonia volatilization from litter usually require good housekeeping, proper ventilation for moisture control, and perhaps chemical additives. Remediation can be costly but prevention is cost-effective and beneficial to farm workers, poultry, and the environment.
Ammonia emissions from litter during broiler production adversely affect bird health, increase ventilation costs, and cause significant ammonia emissions to the air. Improving nitrogen efficiency by feeding the flock proper amino acid diets can reduce the content of nitrogen in excrement and help control ammonia emissions.
Ventilating the poultry house before you have a problem, for example, when the house is new, the birds are young, and after cleanouts, is essential. Unless the house is properly ventilated at these times, ammonia problems may be just around the corner. Ventilating to prevent the problem will save growers increased heating and ventilation costs later in the growout.
Another tip: don’t let your nose be your sensor. After several years in the poultry business, you may tolerate a higher level of ammonia in the air than is good for you or your operation. First-time growers may be sensitive to ammonia at 10 parts per million; seasoned growers may be unaware of levels as high as 60 ppm. Operating costs, especially for fuel, will be lower at these levels, but so will the birds’ performance.
Controlling house humidity will help you manage the ammonia and prevent litter from caking; it will also help control carbon dioxide, dust, and oxygen levels. Humidity in the house should be kept (ideally) at 50 to 70 percent.
Diluting the moist air inside the house with fresh outside air is the key to humidity control, so watch the weather. Warm, humid days will obviously increase the need for ventilation. Because it can be so difficult to gauge how much fresh air is needed, Georgia’s Cooperative Extension Service has developed a list of timer settings and number of fans needed to maintain the average humidity in a 40 by 500-foot house during the six or eight weeks of growout (see Tables 1 and 2). You will want to check the weather conditions and perhaps consult with the Cooperative Extension office nearest your facility before adopting these tables.
Table 1. — Small Birds (30,000).
| Bird Age (Weeks) | Seconds On (5-minute timer) | Number of 36″ Fans |
|---|---|---|
| 1 | 30 | 2 |
| 2 | 60 | 2 |
| 3 | 90 | 3 |
| 4 | 120 | 3 |
| 5 | 150 | 4 |
| 6 | 180 | 4 |
Table 2. — Big Birds (24,000).
| Bird Age (Weeks) | Seconds On (5-minute timer) | Number of 36″ Fans |
|---|---|---|
| 1 | 30 | 2 |
| 2 | 60 | 2 |
| 3 | 60 | 3 |
| 4 | 90 | 3 |
| 5 | 120 | 3 |
| 6 | 120 | 4 |
| 7 | 150 | 4 |
| 8 | 180 | 4 |
Two other tips: First, if you are using the tables, consider the timer settings as minimum suggestions when the birds are young. The settings may be adjusted down slightly during extremely cold weather when the birds are older. To help you determine how much leeway you have, an inexpensive relative humidity and temperature gauge will be as useful as more expensive ammonia meters. The difference in price will be significant: $30 as opposed to $1,500, and the ammonia meter may not last more than a year or two in a poultry house.
Second, be sure to check the drinker line height and pressure. Adding additional water to the house through improper drinker operation will skew the tables and cost you money. It takes about 12,000 cubic feet of air to get rid of a gallon of water. So wasting five gallons of water will increase your ventilation rates by 1,000 cubic feet per minute. If the fresh air also has to be heated, you will probably use an additional half-gallon of propane per hour.
Phosphorus runoff from fields and ammonia entering the air are two problems associated with poultry litter. The amount of water soluble phosphorus in litter varies depending on its source and management. For example,
- fresh broiler litter contains 1.23 grams of water soluble phosphorus per kilogram of litter;
- stacked litter, 2.29 grams;
- dead bird compost, 2.15 grams;
- caged layer manure, 2.68 grams; and
- turkey litter, 3.02 grams.
The addition of certain litter additives has been reported to reduce ammonia levels in the house and to decrease phosphorus runoff when the litter is spread on pasture. The reduction in phosphorus runoff has been as high as 87 percent in some cases. Some research has observed a 30 percent decrease in soluble soil phosphorus.
Other litter additives are available for acidifying the litter to decrease the levels of ammonia in the air of poultry houses. The acidification of the litter is also reported to reduce the levels of bacteria in the litter, thus having a potential food safety benefit.
Follow the manufacturer’s recommendation on the application rate for the additive (pound/square foot). Be sure to follow proper safety precautions in its application.
References
Czarick, M. and M.P. Lacy. 1997. Ammonia levels need to be monitored for ventilation effects. Poultry Times, June 16, pp. 22-23
Felton, G.K. and K.J. Hughes. 2002. Field experiments in reduction of water soluble phosphorus in poultry litter using industrial co-products as amendments. ASAE Paper 02-2037 presented at 2002 ASAE Annual Meeting, July 28-31, Chicago, IL.
Hughes, K.J. and G.K. Felton. 2002. Laboratory reduction of water soluble phosphorus in poultry litter with SWAN-gypsum and filter cake amendments. ASAE Paper 02-2269 presented at 2002 ASAE Annual Meeting, July 28-31, Chicago, IL.
Moore, P.A. Jr. 1995. Phosphorus Precipitation in Poultry Litter with Al, Ca and Fe Amendments. Completed Research, Project 102. Southeasten Poultry and Egg Association, Tucker, GA.
Moore, P.A. Jr., P.C. Daniel, D.R. Edwards, and D.M. Miller. 1996. Evaluation of chemical amendments to reduce ammonia volatilization from poultry litter. Poultry Science 75:315-320.
Moore, P.A. Jr., W.E. Huff, T.C. Sauer, T.C. Daniel, and D.R. Edwards. 1996. A simple method for measuring ammonia volatilization from poultry litter. Presentation at the 85th Annual Meeting of the Poultry Science Association, Inc., July 8-12, in Louisville, KY.
Paul, J.W., P.K. Barton, D. Kermode, and T.A. Scott. 1997. Measuring Ammonia Emissions from Poultry Broilers Fed Balanced Amino Acid Diets. Agriculture and Agri-Food Canada, Pacific Agricultural Research Center, Agassiz, BC, Canada.