Written by: Dr. Jacquie Jacob, University of Kentucky
In relation to poultry production, lime is a generic term used to refer to the manufactured forms of lime. These forms of lime are quicklime, which is calcium oxide (CaO), and hydrated lime, which is calcium hydroxide (Ca(OH)2). The terms whitewash and, less commonly milk of lime, are used to refer to the suspension of hydrated lime in water. For the purposes of this article, lime does NOT include agricultural lime, which is crushed limestone (calcium carbonate). Agricultural lime should not be used in poultry houses.
The use of lime in poultry production can have several effects.
- Lime application to litter increases the pH of the litter. When litter reaches pH 12, cell membranes of pathogens living in the litter are destroyed.
- Lime reduces the nitrogen content of litter by increasing ammonia volatilization. For this reason, it is important to refrain from using lime when the ammonia level in a poultry house is high. Organic producers should remember that hydrated lime is not permitted for deodorizing animal wastes in organic production. For additional information on controlling ammonia in poultry houses, refer to the page on the effectiveness of litter treatments for the reduction of ammonia volatilization in broiler production.
- Lime decreases soluble phosphorus, thereby reducing phosphorus levels in the runoff.
The routine of cleaning and disinfecting equipment and the poultry house between production cycles is key to controlling diseases. In addition to cleaning and disinfecting, producers can use lime in poultry houses to control pathogens (and reduce fly problems). According to current research, lime is effective at preventing the following poultry diseases:
- Avian influenza
- Newcastle disease
The University of Georgia researchers found that adding 15 pounds of quicklime to every 100 pounds of used litter and turning the litter every other day for 10 days reduced bacterial loads in the litter with no adverse effects on broilers placed in the house after the 10-day preparation period. Researchers conducting a multiple-trial study using turkey litter, however, encountered contradictory results. In the first trial, the inclusion of up to 5% lime in turkey litter improved poult performance. In a subsequent trial, the inclusion of 5% lime in the litter did not improve poult performance.
Producers should exhibit great care when using lime in poultry houses. Lime is caustic to organic matter and destroys debris in addition to pathogens. Lime also burns the footpads of birds if it is left on the ground or floor. It is important to take animals out of the area before treating the area with lime. Also, working with lime is extremely dangerous. Dust inhaled or exposed to the eyes can cause severe burning of the eyes and mucous membranes. When using lime, poultry producers should wear personal protective equipment.