A Review of Literature Concerning Odors, Ammonia, and Dust from Broiler Production Facilities: 2. Flock and House Management Factors

Transcription

1 2004 Poultry Science Association, Inc. A Review of Literature Concerning Odors, Ammonia, and Dust from Broiler Production Facilities: 2. Flock and House Management Factors J. B. Carey,*,1 R. E. Lacey, and S. Mukhtar *Department of Poultry Science Texas A&M University, College Station, Texas ; and Department of Biological and Agricultural Engineering, Texas A&M University, College Station, Texas Primary Audience: Extension Specialists, Poultry Scientists, Poultry Farm Managers SUMMARY Confinement buildings are one of the most likely sources of odor in a broiler operation. The buildings must be ventilated, either mechanically with fans or relying on natural airflow, to prevent animal mortality and enhance animal health. Consequently, odors generated within the building are carried to the surrounding environment by the ventilation system. This review addresses the management of those factors that affect the production and removal of odorants in a broiler production operation. Published literature does not specifically discuss odor generation within broiler houses. Several studies deal with ammonia (an odorant gas) or particulate matter (a pollutant thought to carry odorant gases) emissions in broiler houses. These studies are discussed and inferences are made about the generation of odors under similar conditions. Conditions that lead to higher moisture in the litter tend to increase ammonia release, and by inference, more odorant release. Higher litter moisture is presumed to encourage greater microbial degradation of uric acid excreted by the birds into the litter and release more ammonia. Evaporative coolers may produce excess water droplets that fall to the litter rather than evaporate to cool the incoming air. Broiler houses that use misting systems generally have higher moisture content in the litter at the inlet end of the house. Either type of evaporative cooling system may also reduce litter drying rates by increasing humidity levels within the house. At the other extreme, low litter moisture could lead to the production of more particulate matter (i.e., dust), a pollutant that can transport odors to the atmosphere. The optimum litter moisture content that can minimize odorant and dust release is somewhere within the range of 25 to 35%, but exact values for optimum balance depend on numerous house-specific conditions. Changes in dietary nutrient levels can alter the production of ammonia by varying the amount of nitrogen available; however, most currently researched methods show negative impacts on productivity. Management of watering devices is critical to controlling litter moisture. Proper water equipment maintenance and operation are part of daily house management strategies to control litter moisture and, therefore, dust and odor. Key words: broiler production, odor, litter management 2004 J. Appl. Poult. Res. 13: DESCRIPTION OF PROBLEM Production of broiler chickens in the US is primarily done within enclosed structures in which the floor is covered in an absorbent material (i.e., litter). Conditions within these confinement buildings are managed to optimize bird health and productivity. Factors that affect the 1 To whom correspondence should be addressed: j-carey@tamu.edu.

2 510 interior conditions include seasonal climate and weather conditions; building ventilation, heating and cooling; and factors that affect the litter (e.g., feed spillage, flock husbandry, litter management). These factors are interrelated in establishing the composition of the interior air in the building. Because commercial broiler production is totally confined, the air in the building contains all of the materials emitted to the atmosphere; some of which are potential pollutants (e.g., ammonia, dust, and odorants). HOUSE AND SITE FACTORS JAPR: Review Article The American Society of Agricultural Engineers [1] has suggested separation distances for site selection of animal production facilities from residential developments (1 mi) and individual rural residences (0.25 to 0.5 mi). Many states have regulatory requirements that establish minimum set-back distances for broiler production facilities. Regulatory constraints notwithstanding, it is best to locate broiler production facilities such that impact on surrounding property is minimized. Local airflow and human traffic patterns may necessitate distances in excess of those stated above to prevent negative impact. In a study of broiler and pig slurry in The Netherlands, Misselbrook et al. [2] used a series of mathematical models to demonstrate that broiler house odors were more intense than the pig slurry, but broiler house odors had a greater slope of intensity on concentration (1.61 for swine compared with 2.35 for broilers) and would, therefore, be easier to abate. A greater slope of intensity means that smaller reductions in concentration yield greater reductions in odors. The models thus developed for the relationships between odor concentration and odor intensity could be useful in determining the required abatement strategy to render the odor acceptable. The effectiveness of any control measures, when used in conjunction with such models, could establish minimum acceptable distances between the source of an odor and potential complainants. Due to regulatory constraints, ammonia emissions are of utmost importance in the UK. Phillips et al. [3] used a ranking system to elucidate approaches to livestock management and waste storage that had feasibility to reduce ammonia emissions. Those factors related to poultry house and flock management include dietary manipulation, adequate bedding, exhaust air cleaning, and use of ventilation systems to dry litter. LITTER MANAGEMENT Management of broiler litter to reduce ammonia volatilization is largely a matter of controlling litter moisture and ph. Control of litter ph over the life of the flock has proven to be a difficult task. Reece et al. [4] demonstrated that litter ammonia release was negligible at litter ph below 7. Ammonia release began when ph was near 7 and reached a maximum at ph 8 and above. These researchers examined treating the litter with monobasic calcium phosphate at 0.4 and 1.0 kg/m 2 or phosphoric acid at 0.4 kg/m 2 in an attempt to adjust litter ph during growout, but no treatment was effective after 17 d. Ellicott and Collins [5] modeled ammonia release from broiler houses and found litter ph, temperature, and moisture content (in that order) to impact ammonia release. Carr et al. [6] found that ammonia concentration increased with increases in litter ph, temperature, and moisture level. They stated that increased ventilation caused a decrease in ammonia concentration and that litter moisture level should be below 35% to reduce ammonia concentration in the building air. Amon et al. [7] studied litter treatment with a commercial yucca extract (De-Oderase) and a zeolite (clinoptilolite) fed at 2% of the diet and spread on the litter at 1.6 kg/m 2 in concrete and brick broiler houses in Slovenia. The treatments had no positive impact on odor, and clinoptilolite actually increased ammonia release. FLOCK HUSBANDRY Flock husbandry encompasses a variety of factors that impact odor and dust. Litter depth can be a factor as Al Homidan et al. [8] observed that litter ammonia levels were higher in treatments with less bedding material. Dietary factors are discussed more fully in a subsequent section. Ferguson et al. [9] examined the impacts of dietary CP levels on litter ammonia and found that their dietary treatments had no significant impact on litter ammonia. They did, however, confirm the relationship between higher litter moisture

3 CAREY ET AL.: REVIEW: FLOCK AND HOUSE MANAGEMENT 511 and increased litter ammonia. Increases in litter moisture from approximately 56 to 60% resulted in an increase in litter ammonia release. The positive impacts of litter management can also improve broiler health. McGovern et al. [10] demonstrated that oiling broiler litter with feedgrade canola oil reduced dust levels by up to 32%. Willis et al. [11] used evaporative cooling systems to control broiler house dust. Treated pens had higher ammonia and moisture but lower dust. Broiler BW of the treated pens were higher. Dietary Influences Terada et al. [12] studied the impact of feeding lactosucrose in broiler diets on cecal microbes and odor compounds in cecal contents. These researchers reported significant reductions in cecal ammonia, phenol, and cresol among birds fed lactosucrose. They also reported increases in cecal acetic acid and butyric acid among birds fed lactosucrose. Pen ammonia levels were significantly lower in the lactosucrosefed birds, and the researchers observed that pen odor was reduced in the lactosucrose-treated groups. Elwinger and Svensson [13] examined the impact of protein level on ammonia emission and litter nitrogen in broilers in Sweden. Based on nitrogen balance estimates, they calculated that the loss of nitrogen attributable to ammonia losses increased as dietary protein level increased but numerous measurements of litter ammonia did not detect any differences in ammonia volatilization from the litter. An initial experiment by Ferguson et al. [9], examining the impact of low CP on broiler growth and litter composition, found no impact on litter ammonia levels but did report significant reductions in litter nitrogen levels. In other work, Ferguson et al. [14] compared low, medium, and high CP levels in broiler diets. The low and medium treatments were supplemented with synthetic amino acids. Litter ammonia levels tended to be lower for the low and medium CP treatments compared with the high treatment. Litter ph of the low treatment was significantly reduced compared with the high treatment group. Litter moisture and total nitrogen was significantly reduced between the high and medium group and also between the medium and low treatment group. Si et al. [15, 16, 17] studied the impacts of lowering CP levels accompanied by supplemental synthetic amino acids in an attempt to reduce nitrogen excretion while maintaining growth and feed efficiency in broilers. Reducing CP below 20%, while providing indispensable amino acids, consistently resulted in reductions in BW and feed conversion of the broilers. Extensive work to elucidate specific amino acids that may contribute to the poor performance has failed to determine the necessary amino acids required to restore growth and feed efficiency in lower protein diets. Chavez et al. [18] reported significant differences among methionine sources on the odor volatility of broiler excreta. This could provide additional management strategies to reduce or alter odors from broiler production facilities. Litter dry matter content and nitrogen losses were lower when using nipple drinkers vs. bell drinkers [13]. Presumably conditions favoring reduced nitrogen loss would also favor reduced odor production. However, if the litter is too dry, then increased dust concentrations may occur in the building. Water Systems Guidelines for drinker management in relation to season of the year are provided by manufacturers [19]. Birds drink substantially less water in cooler weather; thus, it is necessary to reduce pressure in drinker systems during cooler weather to prevent wet litter conditions that can lead to increased ammonia release and related problems. Each manufacturer has recommendations regarding drinker pressure for birds of all ages and under all environmental conditions. Additional difficulties occur when house floors are not level. Some form of pressure equalizer or additional regulator is needed in the system to assure proper water pressure throughout the length of the system. General recommendations for finding the proper water pressure involve careful observation of litter conditions surrounding the drinker system. If the litter is wet, the pressure needs to be reduced or the drinker height needs to be raised. Litter age, season of the year, bird age, and equipment condition all

4 512 JAPR: Review Article play a role in determining the proper drinker pressure. COMPOSTING OF LITTER AND MORTALITY Wet litter and dead birds are among the potential sources of odor at a broiler operation. Processing of litter and mortalities by composting helps reduce odors and volumes of waste generated. On the other hand, a poorly managed composting operation will add one more source of odor. Managing a major die-off requires extra attention to the factors that could result in the development of odors. Carcass burial must be completed within the 72 h required by regulations, but it is highly advisable that burial occurs within 24 h. Due to the large number of carcasses associated with a major die-off event, the potential for rapid development of strong odors is of primary concern. Natural Resource, Agriculture, and Engineering Service [20] states that odor control CONCLUSIONS AND APPLICATIONS 1. Proper location of poultry facilities is a key factor in the avoidance of odor-related problems. Other site factors include the potential windbreak walls, tree lines, or fan elbows to improve air mixing. 2. Litter moisture management is key to odor control. This includes ventilation and drinker management. 3. Research has demonstrated that litter ammonia release is negligible at litter ph below Consideration of nutritional factors that influence odor production may be warranted if such changes do not negatively impact bird performance. 5. Management of on-farm mortalities is an important factor in odor management. 1. American Society of Agricultural Engineers Control of manure odors. Pages in ASAE EP Agricultural Engineers Yearbook of Standards. ASAE, St. Joseph, MI. 2. Misselbrook, T. H., C. R. Clarkson, and B. F. Pain Relationship between concentration and intensity of odours for pig slurry and broiler houses. J. Agric. Eng. Res. 55: Phillips, V. R., D. A. Cowell, R. W. Sneath, T. R. Cumby, A. G. Williams, T. G. M. Demmers, and D. L. Sandars An assesment of ways to abate ammonia emissions from UK livestock buildings and waste stores. Part 1. Ranking exercise. Bioresour. Technol. 70: Reece, F. N., B. D. Lott, and B. J. Bates The performance of a computerized system for control of broiler-house environment. Poult. Sci. 64: Ellicott, H. A., and N. E. Collins Factors affecting ammonia release in broiler houses. Trans. ASAE 25: REFERENCES AND NOTES problems are the single biggest threat to a composting operation. They recommend that composting facilities be placed a long distance from neighbors and property lines. The 3 primary sources of odor are raw materials, ammonia, and anaerobic conditions within the compost stack or row. Anaerobic conditions can be eliminated through assurance of proper moisture and aeration. Ammonia odors can be controlled by providing extra carbon sources (such as straw or wood shavings) to the mixture. Strong-smelling raw materials can be eliminated through timely and effective collection and use. Reduction of odors from strong smelling raw materials will not occur until the composting process is well underway. Odors can be reduced by increasing the porosity of the mixture and by covering the compost pile with a layer of peat moss or fully composted material. Compost turning, loading, and transportation tend to increase odors. Control of moisture in raw materials can also reduce odor problems related to excessive moisture. 6. Carr, L. E., F. W. Wheaton, and L. W. Douglas Empirical models to determine ammonia concentrations from broiler litter. Trans. ASAE 33: Amon, M., M. Dobeic, R. W. Sneath, V. R. Phillips, T. H. Misselbrook, and B. F. Pain A farm-scale study on the use of Clinoptilolite Zeolite and De-Oderase for reducing odour and ammonia emissions from broiler houses. Bioresour. Technol. 61: Al Homidan, A., J. F. Robertson, and A. M. Petchey Effect of temperature, litter and light intensity on ammonia and dust production and broiler performance. Br. Poult. Sci. 38:S5 S Ferguson, N. S., R. S. Gates, J. L. Taraba, A. H. Cantor, A. J. Pescatore, M. J. Ford, and D. J. Burnham The effect of dietary crude protein on growth, ammonia concentration, and litter composition in broilers. Poult. Sci. 77:

5 CAREY ET AL.: REVIEW: FLOCK AND HOUSE MANAGEMENT McGovern, R. H., J. J. R. Feddes, F. E. Robinson, and J. A. Hanson Growth performance, carcass characteristics, and the incidence of ascites in broilers in response to feed restriction and litter oiling. Poult. Sci. 78: Willis, W. L., M. D. Ouart, and C. L. Quarles Effect of an evaporative cooling and dust control system in rearing environment and performance of male broiler chickens. Poult. Sci. 66: Terada, A., H. Hara, J. Sakamoto, N. Sato, S. Takagi, T. Mitsuoka, R. Mino, K. Hara, I. Fujimori, and T. Yamada Effects of dietary supplementation with lactosucrose (4 G -β-d-galactosylsucrose) on cecal flora, cecal metabolites, and performance in broiler chickens. Poult. Sci. 73: Elwinger, K., and L. Svensson Effect of dietary protein content, litter and drinker type on ammonia emission from broiler houses. J. Agric. Eng. Res. 64: Ferguson, N. S., R. S. Gates, J. L. Taraba, A. H. Cantor, A. J. Pescatore, M. L. Straw, M. J. Ford, and D. J. Burnham The effect of dietary protein and phosphorus on ammonia concentration and litter composition in broilers. Poult. Sci. 77: Si, J., C. A. Fritts, P. W. Waldroup, and D. J. Burnham. through amino acid supplementation. 1. Extent to which crude protein may be reduced in corn-soybean meal diets through amino acid supplementation. Abstr Int. Poult. Sci. Symp., Atlanta, GA. Abstr Si, J., C. A. Fritts, P. W. Waldroup, and D. J. Burnham. through amino acid supplementation. 2. Effects of tryptophan: large neutral acid ratios and overall amino acid levels. Abstr Int. Poult. Sci. Symp., Atlanta, GA. Abstr Si, J., C. A. Fritts, P. W. Waldroup, and D. J. Burnham. through amino acid supplementation. 3. Effects of excess methionine from meeting the needs for total sulfur amino acids. Abstr Int. Poult. Sci. Symp., Atlanta, GA. Abstr Chavez, C., T. P. Niemeyer, P. L. Reynolds, R. A. Russo, R. E. Lacey, and J. B. Carey The impact of methionine source on poultry fecal matter odor volatiles. Pages in Proc. Int. Symp. Addressing Anim. Prod. Environ. Issues, Research Triangle Park, NC. 19. Ziggity Systems, Inc Water Works. Issues 2 5. Ziggity Systems, Elkhart, IN. 20. Natural Resource, Agriculture, and Engineering Service (NRAES) On-farm composting handbook. NRAES-54. Cooperative Extension, Ithaca, NY. Acknowledgment This review was in part supported by contract # with the Texas Natural Resources Conservation Commission (Study of Odors and Arsenic Emissions from Poultry Growing Operations).