As the litter goes, so goes the flock! This aphorism holds a strong meaning as it associates with management of the litter and its effect on air quality.Most of the time,litter quality often reflects how well one has managed these systems. This article deals with the litter treatments which are critical in management of the farm and control the spread of the pathogens. Hopefully, the following piece of information will aid in a better knowledge of some important management concepts with built up litter.
The most prevalent obnoxious gas in poultry housing is ammonia, among others producing irritation to the eyes and reducing resistance to infection in poultry. Ammonia is a colourless gas produced from the evolution of uric acid decomposition in chicken manure. Microbial decomposition converts uric acid to ammonia and carbon dioxide which is volatilise into the atmosphere. Many factors influence the growth of these uric acid degrading microorganisms (bacteria and fungi) present in the litter such as temperature, moisture content and pH. The limiting ammonia concentration in poultry houses is recommended to be less than 25 ppm. Blake and Hess, in their report state about continuous exposure to ammonia concentrations of 10 ppm damaging bird’s respiratory system, making them susceptible to opportunistic infectious diseases.
Using litter amendments could be one of the solutions to the above problem. Litter amendment system can acts as an ammonia binder which help in improving the exposure of ammonia to the birds and reduces release of this greenhouse gas into the environment. Litter amendment systems also having disinfectant properties may be used as bio security enhancers in the poultry house. They also reduce the energy consumption by reducing ventilation required during winter season.Moore et al. have reported that the application of alum in broiler houses considerably reduced ammonia levels within three weeks. It stated better poultry performance due to lower ammonia levels in the early growth stage. Furthermore, it lowered the electric bills, as little ventilation was not required to reduce ammonia. Overall, the benefits of using alum were approximately double the cost of investment (To read morehttp://www.ars.usda.gov/SP2UserFiles/Program/212/LivestockGRACEnet/AlumPoultryLitter.pdf).Similar results were obtained when poultry guard was used as a litter amendment, reported by McWard and Taylor. In addition, it also reduces darkling beetle populations and salmonella levels in the litter (To read more McWard, G. W., and D. R. Taylor. 2000. Acidified clay litter amendment. J. Appl. Poult. Res. 9:518-529).
The litter amendment product, USM-98, marketed by UAP Southwest of Pittsburg, Texas, uses a combination of beneficial microbes and enzymes. The manufacturers of these products claim that such treatments allow microbes to work in sub optimal conditions in the litter or improve the conditions in the litter to enhance performance of the microbes. Venting the produced ammonia during layout will result in lower ammonia levels when the chicks are placed in the house later. This result in reduction of ammonia concentration, reduced mortality rate, and improved the bird performance. P.S. the above product is not published in any scientific journals. Also, venting ammonia into the atmosphere pollutes the environment.
Using amendments may offer other economic and environmental benefits:
• Reducing ammonia loss will increase the nutrient value of the litter while improving air quality.
• Reducing ammonia production may reduce ventilation needs and, hence, energy costs in houses that have inadequate ventilation.
• Odor complaints from neighbours may be reduced.
• Pathogen and pest levels in the house may be reduced.
• Water quality may improve because the use of alum can reduce the loss of soluble phosphorus and heavy metals in the runoff from land-applied poultry litter.
Chemicals are also added to the litter to either reduce microbial growth or inhibit the mode of action, there by slowing the decomposition of uric acid. For instance, Phenyl phosphorodiamidate inhibits urease activity, reducing conversion of urea into ammonia. The main disadvantage is that inhibitors are currently not economically feasible to growers.A natural clay mineral, clinoptilolite (a type of zeolite) along with peat tend to adsorb ammonia. However, it has received mix reviews. One report states fair reductions in ammonia, while other study reports large increase in ammonia levels.Alkaline materials such as agricultural lime (CaCO3), hydrated or slaked lime (Ca(OH)2), or burnt lime (CaO) increase litter alkalinity and convert more of the ammonium in the litter into ammonia gas.However, this method releases lot of ammonia into the atmosphere, diminishing the fertiliser value of the litter, giving negative impact on the environment. Furthermore, if the alkaline material is not completely utilised during the layout period between flocks, ammonia levels in the house may increase when fresh manure is added to the litter.
To limit ammonia production, litter moisture below 30%;the litter pH should be below 7.0; and temperature at the level of the broiler’s satisfaction. Acidifies reduce ammonia levels in the poultry house and improve in-house air quality.This not only improves bird performance and health but also may positively impact worker health. Acidifies may decrease microbial loads in the litter, as well as pathogen dissemination to processing plants through the birds, thus becoming a useful bio-security control in the overall Hazard Analysis and Critical Control Point (HACCP) plan. Further acidifies also decrease darkling beetle populations at higher application rates. Finally, a well balanced fertiliser (high N/P ratio) will meet to the requirements of most crops. Overall, acidifiers are the most effective and widely used type of poultry litter amendment.
Currently, there is a growing interest in regulating ammonia emissions from animal facilities at each levels of the poultry industry. Many research studies has shown that litter amendments reduce ammonia levels in the poultry house and improve bird performance and health along with other economic and environmental benefits as well. In brief, the way in which we control built up litter will continue to modify as we are challenged with developing poultry production, welfare,food safety and environmental concerns.