Duration: 10/01/1999 to 09/30/2004

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Statement of Issues and Justification

Poultry production has increased and intensified significantly during the last several decades. With more reliance on climate controlled houses, the complexity of production has also increased substantially. It has become increasingly critical that management strategies optimize efficiency of production, minimize losses from environmental and housing stresses, and maximize animal well-being -- areas of major concern to producers. A multi-discipline, collaborative approach to understanding how to best achieve these goals is necessary because of the enormous complexities of animal-environment interactions.

Related, Current and Previous Work

RELATED CURRENT AND PREVIOUS WORK:

Research conducted under the aegis of Regional Research Project NE-127 ("A Systems Approach to the Evaluation of Environmental Constraints Affecting Poultry Production" [1989-1994] and "Biophysical Models for Poultry Production Systems" [1994-1999]) has provided many significant contributions to understanding of the effects of the physical environment on poultry physiology and productivity.

Current Work: Results of the CRIS search

A CRIS search identified 12 regional research projects including NE-127 that are working on similar or related areas of research with poultry (see Appendix I). Much of our proposed research deals with the effects of thermal environment on poultry. Therefore this area of the current research will be discussed first.

In addition to NE-127 and the stations involved, the following stations and ARS units were identified to have currently active projects related to the thermal environment of poultry production facilities: AL, FL, GA, KY, MS (ARS), NC, SC, and TN. All these stations are involved in the Southern Regional Research Project S-261 "Interior Environment and Energy Use in Poultry and Livestock Facilities". While both NE-127 and S-261 share the common goal to improve production, profitability of poultry operations, there exist numerous distinctive and complementary natures between the two projects. These distinctions and complementation include:

a) Committee Profile and Work Thrust: The S-261 committee consists of primarily agricultural engineers, and its main thrust is to develop and/or evaluate building ventilation and environmental control components or systems that lead to improved interior environment and energy efficiency. By comparison, the NE-127 committee has much greater diversity of disciplines and focuses on establishing the fundamental database for development of the optimal housing and environmental control systems by characterizing physiological, behavioral and performance responses of poultry to critical environmental factors.

b) Project Scope: S-261 encompasses all farm animal species (cattle, dairy, swine, and poultry). The poultry aspect of its work scope focuses primarily on broilers, the major poultry industry for the Southern region. NE-127 is devoted entirely to poultry and its work scope covers all the poultry species of broilers, layers, and turkeys, all of which have a major role in the agricultural economy in the Northeast and/or Midwest.

Thus, we see the efforts by both projects as being highly complementary with each having its own, equally important uniqueness. In fact it has been proposed that the two committees exchange annual reports to enhance prompt information dissemination and avoid unnecessary duplication of efforts.

No projects were identified to systematically quantify the heat and moisture production of modern poultry and their housing systems except those from participants of NE-127. Limited studies have recently been conducted at IA with young turkeys (Xin et al., 1998), breeder chicks (Xin and Harmon, 1996; Han and Xin, 1997), and market-size broilers (Xin et al., 1996).

With regard to ongoing research in behavior and leg problems, no other station was identified as currently active in this topic. Different stations are working on leg problems but focusing on effects of nutrition (AL, AK, MS), physiological and biochemical aspects of leg problems (MI, AK), etiology and pathology of osteomyelitis-synovitis (AK), biomechanical properties of the musculo-skeletal system (GA) and effects of slats flooring systems on leg problems in broiler breeders(GA). Only one station (WA) has an active project in behavior that is focused on cannibalism in laying hens.

There are currently no projects that study all three aspects of the light environment: spectral quality, intensity and duration of light/dark cycles. However investigators in OH, TN, and PA are looking at photoperiod schedules, such as intermittent lighting, to improve layer or broiler production. Other researchers at FL and ARS-Beltsville are looking at light attractants to kill flies in poultry facilities. The FL team is also looking at the effect of UV light from these fly attractants on bird performance.

A CRIS search of the literature shows a paucity of information concerning the use of artificial intelligence and operations research methods in poultry management systems. The poultry work involving Operations Research and Artificial Intelligence noted in the CRIS research came from PA (Roush et al., 1996, 1997; Roush and Cravener, 1997) and the University of Georgia (Patel et al., 1996).

Related work: Studies in thermoregulation

The negative impacts of warm environmental temperatures or heat stress on poultry production have been well documented. Less defined are the physiological mechanisms and strategies to reduce the negative impacts. An increase in environmental temperature decreases feed consumption and growth of meat type poultry ( Deaton et al., 1978; Reece et al., 1972; Reece and Lott, 1983; Suk and Washburn, 1995). Heat stress alters the rate of thermal panting and blood flow patterns. Depressed gastrointestinal blood flow may impair energy assimilation and contribute to poor performance.

In layers, increased environmental temperature reduces egg mass and shell quality, but much remains to be elucidated about how egg production is disrupted. Homeostasis of calcium metabolism, as well as of the reproductive hormones (LH; progesterone, P4; estradiol, E2) is disrupted within 24h of onset of acute HS in unacclimated birds (Mahmound et al., 1996; Novero et al., 1990). Progesterone release by ovarian granulosa cells is inhibited by heat stress even with challenge by the releasing hormone (LH). Heat shock proteins (hsp) may alter progesterone release.

Hsp90 is of particular interest for its role intracellular transport and possible activation of avian progesterone receptor function (Kost et al., 1989) as well as possible involvement in activation of other steroid receptors (Carson-Jurica et al., 1989). Increases in hsp90 in response to heat stress could flood progesterone receptors, making activation of the receptors more difficult and resulting in the decreased ability of granulosa cells to produce and secrete progesterone following heat stress of the hen (Novero et al., 1991).

The main cooling mechanism in the fowl is convective heat transfer to the skin surface, but because of the great insulatory properties of the feathers, vasodilatation is only likely to achieve substantial heat losses in the comb, shanks, and undersurface of the wings (Hutchinson and Sykes, 1953; Appleby et al., 1992a). Recent research indicated that local peripheral tissue cooling during heat stress can shift visceral and peripheral circulatory patterns and improve production. At high temperatures the birds' feet provide a site to modulate heat dissipation through conductive heat loss (Muiruri and Harrison, 1991 a; Reilly et al., 1991) and several other physiological mechanisms (Hillman et al., 1982; 1985). For example, access to a cooled roost improved egg production during heat exposure (Staten et al., 1986; Flynn et al., 1984).

As air temperature rises, animals increasingly rely on latent heat loss. When high air temperatures are combined with high humidity, the effects can be devastating. In order to assess the relative effects of temperature and humidity, temperature-humidity indices (THI) have been developed and used by researchers for several species (ASHRAE, 1981). For poultry, THI's have been developed for laying hens (Zulovich and DeShazer, 1990); turkey hens (Xin et al., 1992); and growing male turkeys (Brown-Brandl et al., 1997). No THI's have been developed for broilers, which suffer heavy losses during periods of acute heat mortality stress annually.

Research-based data are also meager on the effective environmental temperature (EET) for poultry that integrates the combined effects of air temperature, humidity, velocity, and possibly radiation, although tunnel ventilation (to increase air velocity and thus convective heat dissipation of the birds) has been routinely used in the industry to cool the birds. Timmons et al. (1995) proposed a new control algorithm that uses a time integrated thermal history of the birds as opposed to the conventional, instant thermal conditions, to better recover the heat stress accumulated during the hot period of the day. One critical issue that remains to be further investigated regarding this approach is the optimal time interval of integration, which will likely depend upon animal species, age, and acclimation history.

Current literature data on moisture production have a major limitation in that they represent only the latent heat loss from the birds. Although the data were appropriate for evaluation of bird thermoregulation, they would be incomplete as a database for building ventilation designs where heat and moisture from both the birds and their surroundings must be considered. The partition of total heat production into sensible and moisture modes is undoubtedly affected by the housing components (e.g., open trough drinker vs. nipple drinker), waste handling system (liquid vs. solid manure; belt vs. litter), and management schemes (e.g., manipulation of photoperiod). For instance, a recent study on young tom turkeys during 5-week brooding/growing period (Xin et al., 1998) revealed a 4% (for body mass= 0.1 kg) to 282% (for body mass = 1.0 kg) higher moisture production and a corresponding 2% to 107% lower SHP for the current study, as compared with those in the ASAE Standard (EP 270.5) (1998). Consequently, the discrepancy in the minimum ventilation requirement for moisture control ranged from 55 to 457% between the values based on the current moisture production data and the values of the literature recommendations (MWPS, 1990).

Related work: Studies related to the aerial environment

Aerial ammonia in poultry facilities is usually found to be the most abundant air contaminant. Ammonia concentration varies depending upon several factors including temperature, humidity, animal density and ventilation rate of the facility. Maghirang et al. (1991) concluded that overall air quality was poorest at locations furthest from the exhaust fans with significant differences in air temperature and NH, levels and that ventilation rate appears to be the most important factor influencing indoor air quality. Xin et al. (1996) showed that 8 to 9 times the normal minimum ventilation rate, i.e., for new bedding was required for NH3 control on the first day of brooding for broiler houses using old litter.

The effect of aerial ammonia on bird performance has been widely studied. Birds exposed to ammonia showed reductions in feed consumption, feed efficiency, live weight gain, carcass condemnation, and egg production (Charles and Payne, 1966a; Quarles and Kling, 1974; Reece and Lott, 1980; Xin et al.,1987). High ammonia exposure was found by Xin et al. (1987) and Charles and Payne (1966b) to reduce respiratory rate by 7 to 25% in layers. The reduction of egg production under heat stress may have been related to the altered respiratory pattern (Xin et al.,1987).

Studies on the effects of dust in animal housing generally indicate potential for adverse effects on the health, growth and development of animals (Janni et al., 1985; De Boer and Morrison, 1988; Feddes et al., 1992). Respirable aerosol particles within poultry housing have been shown to decrease bird growth (Butler and Egan, 1974), increase disease transfer within flocks (Hugh-Jones et al., 1973; Beaseley et al., 1970; Simensen and Olson, 1980), and increase condemnation of meat at processing plants (Hugh-Jones et al., 1973). Dust might affect the health and the growth rate of livestock in four ways: 1) as a physical irritant of the respiratory tract; 2) as a carrier of toxic chemicals and odors; 3) as a carrier of pathogenic microorganisms; and 4) as a carrier of commensal, non-pathogenic bacteria (Harry, 1978). The size and shape of the dust particles determines the extent of penetration and deposition of the particles into the respiratory system. Dust helps to concentrate the non-pathogenic microorganisms to very high levels, which may interfere with normal function and predispose the animal to further health problems. In addition, dust absorbs and carries gases and moisture (Day et al., 1965; Bumett, 1969; Scott et al., 1983; Donham et al., 1986; Hinz and Krause, 1987) and can thus transport gases such as ammonia deep into the lungs (Hillman et al., 1988). Dust plays an important role in the transport of trace gas and odors inside and outside the animal building. Dust can also carry toxins (Attwood et al., 1987).

Ammonia and dust also interact to worsen the air quality impact. Results of air quality monitoring in commercial turkey grower barns have indicated that ammonia and dust are significant contributors to the incidence of air sacculitis and resulting condemnation in tom turkeys (Janni et al., 1984; Janni et al., 1985; Janni and Redig, 1986).

There are three basic methods used in an attempt to control air contaminant levels in poultry facilities: 1) Reduce contaminant production at the source; 2) Remove contaminants from the air; and/or 3) Reduce gas contaminant concentration by dilution (ventilation). The most effective method is to reduce release of contaminants from the source, or to at least intercept and remove them before they reach the workers and animals.

Sprinkling small quantities of vegetable oil on floors every day has reduced dust concentration by more than 80 percent in swine facilities (Zhang, et al., 1996). High animal activity levels release large quantities of particulates into the air, so management strategies to reduce agitation of animals are helpful. Electrostatic precipitators or room air filters can reduce dust problems and air scrubbers have the capability to remove gases and particulates, but practical, economical systems need to be developed.

Reducing ammonia generation might be obtained through the use of litter additives that affect ammonia release or by decreasing the amount of available substrate (organic nitrogen) through diet manipulation.

Litter pH has been shown to be a critical component in the control of ammonia release in floor rearing management conditions (Carr et al., 1980). Chemical additives which decrease litter pH appear to be most effective (Hulet, 1998). Recent research has emphasized alum application (Moore et al., 1995). Effectiveness appears to be influenced by other environmental conditions such as litter moisture and temperature. Developing predictive ammonia models with consideration of litter additives and including economic considerations is needed for making recommendations to producers.

Decreasing diet protein levels has the potential to decrease nitrogen excretion. Recent research at Kentucky (Ferguson et al., 1998a, 1998b) showed lowered litter nitrogen concentrations when broilers were fed diets with reduced protein content. However, some reduction in body weight was observed which could be corrected with supplemental lysine. Waibel (unpublished, University of Minnesota) has indicated the potential to reduce diet protein content in turkey diets to 50% of the NRC (1994) recommended levels with appropriate amino acid supplementation. The next step is to demonstrate the degree of reduction in nitrogen excretion and ammonia generation.

Related work: Studies related to the light environment and photoperiod

Several studies have shown that energy efficient compact fluorescent lamps do not adversely affect bird performance for layers (Darre and Spandorf, 1985; Darre, 1991a; Widowski, et al. 1992), or broilers (Zimmerman, 1986; Andrews and Zimmerman, 1990; Scheideler, 1990).

Longer lamp life along with energy and monetary savings have been shown to outweigh the initial cost of the lamps (Darre, 1986; Darre, 1991 b; Darre and Rock, 1995). Other types of lamps, including high and low pressure sodium lamps, have been tested with broilers without adverse results (Zimmerman, 1986). More recently a variety of alternative lighting programs have been compared to 23 hours of light: 1 hour of dark for broilers with the observation that intermittent lighting schedules resulted in heavier body weights (Buyse et al. 1996). Gordon (1997) reported that reducing the hours of light provided to growing broilers also reduced mortalities due to sudden death and ascites. Classen et al. (1991) found programs with increasing photoperiod were superior to near continuous light for the health of growing broilers.

Studies on the quality of wavelength have been conducted in both laying hens (Pyrzak et al., 1986, 1987) and broilers (Prayitno et al. 1997) showing that birds will respond to all wavelengths of light, but broilers may be more active under red light than under blue or green, but grow to slightly heavier weights under green lights. Widowski et al. (1992) showed that laying hens prefer compact fluorescent lamps over incandescent lamps. What is lacking in the literature are studies defining the interaction of wavelength, intensity and duration on layer performance or broiler growth and the use of newer energy efficient lighting devices, such as the electronic lamps, electronic ballasts for CF lamps and high pressure sodium lamp dimming devices.

Related work: Lea disorders, perch design and behavior

Leg disorders in broilers are due to a large number of bone, muscle and tendon deformations of different pathology and are often of multi-factorial origin (Nairn and Watson, 1972; Riddell, 1981; Pierson and Hester, 1982; Classen, 1992; Edwards, 1992; Leach and Lilburn, 1992). Important factors contributing to the high incidence of leg abnormalities are genetic selection and the use of high-energy diets for rapid growth (Rink et al., 1980; Nestor, 1984; Edwards and Sorensen, 1987; Lilburn et al., 1989; Leterrier, 1992). Other factors, such as environmental quality (for review see Hester, 1994), and the level of exercise of the birds (Newberry et al., 1988; Farm Animal Welfare Council, 1992; Kestin et al., 1992; Elson, 1993) may also play a very important role in the incidence of leg abnormalities.

Leg weakness and lameness can have immediate results such as decreased food and water consumption and litter eating (Rowland, 1989; Kestin et al., 1992). Increasing the level of activity in broilers might be one of the most cost-efficient and practical management procedures to reduce leg abnormalities (Hester, 1994). In fact, many positive results obtained with different lighting programs (Hester et al., 1983; Classen and Riddell, 1989; Renden et al., 1991), and feed restriction programs (Rizk et al., 1980; Lilburn et al., 1989) may be due to the higher level of activity of the birds under those conditions (Hester et al., 1983; Lilburn et al., 1989; Hester, 1994).

Although there are several methods to increase the level of exercise of the birds such as to increase availability of space (Estevez et al., 1997), perches have been used extensively in different avian species to increase exercise. Perch use has been shown to increase laying hen bone strength (Hughes and Appleby, 1989; Knowles and Broom, 1990; Appleby and Hughes, 1990; Duncan et al., 1992), increase trabecular bone volume (Appleby et al., 1992b) and increase tibial mass (Hughes et al., 1993). Perches improve the health and well-being of laying hens (Appleby et al., 1992a; Appleby, 1994; Duncan et al., 1992).

Despite the potential benefits of perch use by broilers, few studies have examined its application in the production of broilers (Hughes and Elson, 1977; Simpson and Nakaue, 1987; Reilly et al., 1991, 1992; Newberry and Blair, 1993; Newberry et al., 1995) or broiler breeders (Muiruri et al., 1990, 1991, Muiruri and Harrison, 1991 a, 1991 b). Perches reduced wing flapping during catching prior to transport, which could reduce injuries (Newberry and Blair, 1993). Perches also improve growth rate and might play an important role in reducing heat stress if their design is adequately combined with a cooling system (Muiruri et al., 1990; Reilly et al., 1991).

Current work: Pulmonary hypertension syndrome (PHS ascites)

Any one or more of the following general factor categories can cause PHS: genetics, nutrition, management, environment, incubation, and disease. The specific factors that appear to be most important include: inadequate environmental conditions during incubation (Odom, 1993), limit oxygen uptake by the blood in the lung (i.e., respiratory disease, high altitude), inadequate house ventilation (ammonia, dust, or carbon monoxide build-up), or factors that increase the need and use of oxygen, such as an increase in basal metabolic rate with cold exposure, and rapid somatic body growth (for an excellent review, refer to Julian, 1993 and Wideman et al., 1995).

Interactions between the general and specific causative factors may lead to a similar endpoint in this disease (i.e., PHS). Chronic pulmonary hypertension as a physiological consequence of interactions has been suggested by researchers (Huchzermeyer and DeRuyck, 1986; Julian, 1993; Maxwell et al., 1986; Peacock et al., 1989) as being the primary causative factor.

In mammal research, it has been shown that the production of vasoactive compounds such as synthesis of nitric oxide (NO, the endothelium derived relaxing factor, Palmer et al., 1987; Palmer et al., 1988) and synthesis of endothelin-1 (ET-1, a powerful endothelium-derived vasoconstrictor, Yanagisawa et al., 1988) participates in the regulation of vascular function (Rees et al., 1989). Furthermore, the biosynthesis of NO occurs within endothelial cells via L-arginine (L-arg) and synthesizes the formation of L-citrulline and NO. Under certain conditions, treatment in vitro and in vivo with L-arg attenuated the constriction and augmented the relaxation of blood vessels (Eddahibi et al., 1992; Imaizumi et al., 1992). These results suggest that the basal endothelial synthesis of NO from L-arg and/or the release of NO, contribute to normal vascular tone (Eddahibi et al., 1992; Imaizumi et al., 1992; Palmer et al., 1987; Palmer et al., 1988).

Additionally, researchers have suggested that the availability of endogenous L-arg is an important limiting factor for NO synthesis (Eddahibi et al., 1992; Imaizumi et al., 1992; Kuo et al., 1992; Palmer et al., 1988). In some diseases such as pulmonary and essential hypertension and atherosclerosis (Kuo et al., 1992; Panza et al., 1993) or in experimental models of acute and chronic hypoxic pulmonary hypertension (Adnot et al., 1991; Eddahibi et al., 1992; Johns et al., 1989; Liu et al., 1991), the synthesis of NO may be reduced because of a lack of L-arg substrate or another flaw in the NO signaling cascade. The precise mechanisms of the endothelial cell impairment remain to be fully established.

L-arg is an essential amino acid for avian species. Birds lack the enzyme carbamoyl phosphate synthase (Tamir and Ratner, 1963a; Tamir and Ratner, 1963b) required for L-arg synthesis. Therefore, the bird has to ingest, absorb and circulate dietary arginine for normal endothelial cell NO production. Supplementing L-arg in the chicken diet at levels higher than required for adequate growth rate may allow synthesis of more NO in the chicken and may influence disease resistance (Dietert et al., 1994; Taylor et al., 1992) especially to PHS (Wideman et al., 1995).

Current work: Modeling technical and economic responses

The scientific effort is directed toward the end of predicting via the means of understanding. Its superstructure is built on the faith that causal relationships are inherent in all phenomena. Therefore, the charge of the scientist is to systematically proceed toward discovery, revelation and utilization of these intrinsic properties. Modeling is a methodology that assists in accomplishing this charge by abstracting from reality in a manner that maintains the essential inherent causal relationships but reduces complexity enough so that explanatory and thereby inference powers are enhanced.

Rahn (1977) presented a way that strategic planning models can be used to make economic-based decisions that incorporate both physical relationships and market conditions. Also, since both physical relationships and market conditions are time related, dynamic economic models typically need to consider investments in assets that will yield flows of services over more than one time period, likely have an impact on income tax considerations as well as explicit time value of money considerations. Rahn (1978) presented a modeling procedure that can be used to appropriately appraise capital expenditures and their associated net revenue streams. Both of these techniques are complementary to other project activities focused on discovering and characterizing causal relationships of poultry to environmental factors and are crucial in ascertaining their economic merit and commercial adoption prospects.

Artificial Intelligence and Operations Research Methods offer systematic methods of distilling information for making prescriptive decisions. Collaborative studies carried out between AR and PA have shown that artificial neural network models can be developed based on physiological inputs and outputs for diagnosis of ascites in broilers (Roush et al., 1996, 1997).

It is interesting to note that the Edelman prize for Management Science Achievement (given by the Institute for Operations Research and the Management Sciences) was given to Sadia, a poultry company in Brazil. Using the principles of operations research, the company saved over $50 million over a three year period as a result of (1) better conversion of feed to live bird weight, (2) improved utilization of birds to produce more than 300 products classified by weight range, taking into account weight variation between and within flocks; (3) almost 100 percent fulfillment of daily production plans with increased output of higher value products; (4) greater flexibility and reduced lead time in meeting market demand; and (5) timely and wide ranging studies of different price and demand scenarios (Taube-Netto, 1996). The limited application of Operations Research/Management Science application in poultry science research in the USshould give cause for concern for poultry scientists.

Objectives

1. To quantify physiological responses of poultry to critical biophysical factors and to integrate these with innovative field-tested techniques to solve poultry production problems.
   
2. To develop, evaluate and validate mathematical models appropriate for application to poultry production based on data generated in response to time-dependent changes of the environment with resulting economic implication (Objective 1).
   
3. 
   

Methods

Objective l: Characterize physiological and behavioral responses of poultry to critical environmental factors

Thermal Environments

The effects of hot environments on poultry well-being and production are well documented. As ambient temperature increases above thermoneutrality, feed consumption and growth rate decrease and abrupt extreme thermal stress produces significant losses in all production settings. As temperature rises, animals increasingly rely on latent heat loss; when high temperatures are combined with high humidities, the effects can be devastating. These adverse effects include elevated mortality, reduced growth rate, reduced egg production and quality, and disrupted physiological and behavioral equilibrium.

In the following protocols, various techniques and or technologies developed under the current NE-127 will be used. Calorimeters were designed at NE and built jointly by NE and MD; and others were built at IA and IL. Each of these calorimeters was designed to evaluate a specific animal-environment interaction and their uses are mutually complementary. Cool roosts were initially experimented with at IL and their use and applicability were tested in cooperation with MD.

Specific Experimental Protocols:

1) NE and MD, in collaboration with IL and IA will determine the relative effects of air temperature (T) (25-400C), relative humidity (RH) (40-80%), and velocity (V) (0.2-2.0 m/s) in broiler chickens at 5, 6, 7 and 8 weeks of age (after they reach homeothermy). Four identical indirect calorimeters (1.2x1.5x1.5 m) will be used and modified as needed to generate the TRH-V conditions. They are located within a 3.60.20.6 m environmental chamber that provides preconditioned air. Each bird will be exposed to a T-RH-V combination for 2 hours or until the body core temperature reaches 430C. A PC-based, automatic measurement and data acquisition system will be used to continuously collect the following physiological response variables of the birds: respiration rate, core body temperature, C02 production rate, OZ consumption rate, and moisture production rate. The procedures detailed above will be applied in subsequent studies to broiler chickens of the same ages under the same T-RH-V conditions, but with modification of the NE calorimeters to provide cool roosts for perching and for use as a heat sink. This study will also contribute data to development of temperaturehumidity index (THI) at various air velocities for broilers as described in objective 2.

2) MD, in collaboration with IL and NE, will investigate the effects of conductive heat transfer on the incidence of leg problems in broilers during periods of heat stress. Cold water perch systems of various designs and at various locations within pens will be evaluated.

3) NE and IA will address basic and applied aspects of laying hen responses to thermal stress; basic mechanisms will be investigated at NE and applied commercial evaluations at IA. In addition, IA and NE will jointly evaluate the efficacy of the low pressure sprinkling versus high pressure fogging developed at IA versus cool roosts in alleviating heat stress in hens. IA will develop the control algorithm and collect data on production and the environment; NE will investigate hormonal, immunological and cellular affects of heat stress, including samples from hens in the IA studies. IA, in collaboration with IL and NE will evaluate the various cooling methodologies on physiological responses in simulated laboratory heat stress conditions.

4) IA, in collaboration with IL, will systematically measure heat production (HP) and moisture production (MP) data for modern poultry strains reared under current housing and management systems. Precise data are critical for proper design and operation of ventilation systems. Lab-scale measurements will be conducted to differentiate HP and MP of the bird from those of the system. Field measurements will also be conducted to verify partitioning of total heat production (THP) into sensible heat production (SHP) and MP. These new data will be used to update the literature and ventilation recommendations.

5) The data collected in the above studies will be analyzed for their economic ramifications by MI (see Objective 2).

6) Nonlinear models will be developed by PA with artificial intelligence tools, of temperature and humidity relationships to biological responses from the above studies (see Objective 2).

Expected Outcomes:

Broiler responses to temperature-humidity combinations change with age and body size. The cool roosts are expected to decrease the effect of humidity, reduce panting stress, and reduce incidence of leg problems. Laying hen experiments will provide a better understanding of basic mechanisms disrupted by heat stress. The efficacy of the high-pressure fogging and the lowpressure sprinkling systems as cost-effective alternatives) for air quality control in caged layer houses will be demonstrated. If proven technically desirable, guidelines on the system design and operation will be established. An updated HP and MP database will be established for more precise design and operation of environmental control systems.

Aerial Environment

Ammonia and dust are major factors affecting both flock performance and worker health. In addition as production units concentrate in small areas, release of ammonia and dust becomes an environmental concern. Effective strategies need to be identified to abate gas and dust emissions in order to improve flock health and lessen worker exposure.

Specific Experimental Protocols:

IL and MN will investigate the application of vegetable-based oils to manure and litter. An initial study will be done by IL to determine the potential of spraying a small amount of vegetable oil onto manure surfaces on alternate days for reducing dust and gas emissions in laying hen facilities. Individually caged hens will be placed in the IL Convective Calorimeter and Mass Gas Generation Chamber (I-CAG) for periods of about two weeks. Each test will run for about two weeks. Environmental conditions in the chambers will be controlled to operate at thermoneutral conditions. The manure will accumulate and undergo anaerobic decomposition by the second week. Data collected will include: ammonia levels, hydrogen sulfide levels, dust levels, oxygen consumption, carbon dioxide production, and water production. MN will extend oil application to litter based housing systems for turkeys in anticipation of production times most likely to result in high levels of dust from bird activity (e.g., loadout for marketing) and during times of low relative humidity (e.g., the winter season). Dust will be measured and comparisons will be made between a control and various oil application regimens. IA will examine the efficacy of fogging and sprinkling water inside commercial high-rise layer houses on reduction of aerosols, especially ammonia and dust. For aerosol suppression, water application rate and application intervals will be determined by monitoring the dynamic profiles of the aerosols following each application.

MD, MN, NE, and IA will collaborate to collect data and develop/refine models of ammonia release from broiler litter and turkey litter. Ammonia levels will be measured in chambers or production units with different temperatures and relative humidity, litter moisture, pH and ventilation rates. Litter additives, such as alum, ferrous sulfate or other sulfur-based compounds, will be used as recommended by the manufacturer. Combinations of litter additives and ventilation rates will be tested. Weekly manure analysis of the litter base for N, P, K and other minor elements will be determined at MD. Bird performance, processing, feed and non-feed data and water use data will also be collected.

MN will collaborate with IA to determine the effect of feeding reduced diet protein on ammonia production in turkey facilities. Previous research has been conducted to determine the extent of dietary protein reduction that can be accomplished with utilization of supplemental amino acids. Intact protein diet series will be compared with a reduced protein diet supplemented with appropriate amino acids expected to provide adequate growth. Turkeys will be acclimated to chambers and diets prior to determination of total nitrogen balance.

Economic assessment of the results will be made with the collaboration of MI.

Expected Outcomes:

Results from these synergistic studies will provide a database for Objective 2 in developing predictive models on ammonia generation. They will provide practical alternatives and recommendations for ammonia and dust control under commercial conditions.

Responses to Physical Environment

Perch Design

Leg problems in broilers cause financial losses of $80 to $120 million per year because of poor feed conversion, culling and high mortality. Lack of physical activity is directly related to increased incidence of leg problems. One of the most effective and widely used methods for increasing activity levels without increasing available floor space is to provide the birds with perches.

Specifc Experimental Protocols:

MD and IL will collaborate to study reduction of leg disorders by increasing level of activity and exercise using perch designs adapted to the physical conditions of broilers throughout their life (e.g. horizontal vs. perches at an angle). Potential benefits of perch availability on leg disorders at high rearing densities will also be studied.

Expected Outcomes:

Data generated from these studies will be used to formulate recommendations for perch design and application to poultry systems for improved bird performance and well-being.

Light Environment Spectral quality, intensity and duration of light/dark cycles are primary concerns in poultry production, but cost effectiveness is a primary factor in the adoption of energy-efficient lighting devices by poultry producers. As new devices come on the market, there is a hesitancy to be the first to use it on a commercial poultry farm. Sound research data is required to encourage adoption of these lamps by producers.

Specific Experimental Protocols:

CT, MD and NE will collaborate on studies of the effects of light environment on chickens. The studies will examine the light sensitivity of poultry to various sources of illumination: incandescent, fluorescent (miniature and circular types), mercury vapor, and high- and lowpressure sodium lamps. These studies will examine the behavior, growth and production of different strains of layers and broiler exposed to different sources and intensities of illumination. Data analysis using artificial neural network will predict the proper lighting levels and or types for different strains of birds. Economics of the lighting systems will be evaluated in collaboration with MI.

Expected Outcomes:

Lighting equipment and programs will be recommended to save electrical energy, increase production efficiency of the birds, and improve their well-being.

Pulmonary Hypertension Syndrome (Ascites)

Research by TX has suggested that pulmonary hypertension can be underscored by an unbalanced pulmonary vascular arterial tone and is consistent with the theory that inadequate synthesis and or release of nitric oxide may contribute to an additional impairment with hypoxia (due to an inequality between rapid somatic growth and cardio pulmonary function).

Specific Experiment Protocol

TX will elucidate the role of the vascular endothelium responses using an invasive (isolated vessel assay) and non-invasive techniques (electrocardiograph and echocardiography) to study PHS. Diet supplements will be developed toward the prevention of PHS. AR will examine the role of air quality in PHS development in broilers.

Expected Outcomes

Certain specifications for environmental conditions to prevent ascites in broilers will be established.

Objective 2: To develop dynamic models of these responses for optimizing technical and economic aspects of poultry production systems

1) Broiler THI model

Data from Objective 1-1 will be used in a multi-dimension rotatable composite design (Montgomery, 1991), with data analyzed by RSREG regression procedure of SAS (1985), using the following equation: y = c0 + c 1 T + c2H + c3 V + c4T2 + c5H2 + c6V2 + c7TH + c8TV + + c91TV + c 1 0THV + e

where y = physiological response variable T = dry bulb temperature, 0C H = relative humidity, V = air velocity, m/s ci = independent coefficients e = random error

Calculation of the THI at each air velocity will be based on the following equation:

Y=c0+c1Tdb+c2Twb where y = dependent physiological variable ci = independent coefficients Tdb = dry-bulb temperature Twb = wet-bulb temperature

THI = C` Tdb + C2 Tab (Xin et al., 1992)

c, + C2 c, + C2 2) Ammonia emission models

Data from Objective 1 will be used to build a predictive model for ammonia release from poultry facilities. Physical factors such as ventilation rate, litter pH, chamber temperature, humidity, and litter moisture will be used to confirm a previously developed model (Carr et al., 1987) and will be modified to include performance responses.

3) Economic models

Partial budgeting models will be specified and utilized to estimate - using representative and standardized market values - the potential receipt and expenditure stream changes implied by the performance results observed in the studied thermal environment states. These net receipt streams will be incorporated into discounted cash flow budgeting procedures and the financial attractiveness of the investments associated with each thermal environment evaluated and compared.

4) Artificial Intelligence and Operations Research Models

Artificial Intelligence and Operations Research Methods offer systematic methods of distilling information for making prescriptive decisions. Artificial neural network models can be developed based on physiological inputs and outputs.

Expected Outcomes:

The THI will change over time. Assuming that to be true, relating body surface area to mass might allow the generation of one THI that could be used for all ages tested. Whether one equation or four are generated, the predictive value of the equation(s) will be of benefit to the broiler industry in anticipating periods of critical T/RH combinations and their effects on health and survivability of birds. The availability of cool roosts will significantly alter the THI, because the birds will be able to dissipate considerable heat through conductive transfer to the roosts. Ammonia emission models will aid industry in management of the poultry house to improve production conditions, and provide data for improved sensor development. Economic model assessments of the investigated environmental modifications will provide an indication of the monetary benefits associated with their adoption and thus, their commercial viability.

Measurement of Progress and Results

Outputs

• Elucidation of the physiological mechanisms of thermoregulation and heat stress and the development of techniques for reducing heat stress.
• Better understanding of how aerial pollutants affect poultry production and development of techniques to reduce aerial pollution in houses.
• Development of water quality guidelines for watering poultry. Better understanding of how photoperiod effects development and production.
• Reduction in energy costs associated with lighting by using fluorescent instead of incandescent lighting.
• Explain how dietary energy schedules that skip-a day feeding programs can reduce the incidence of ascites without a major reduction in weight gain.
• Development of mathematical models that can predict the effects of heat and humidity on poultry production.
• Development of experimental vaccines to relieve stress from mycotoxins and aflatoxin.
• Development of experimental cooling systems including, pads, high pressure foggers, low pressure misters, direct application of water and heat exchange units which all show promise of alleviating heat stress.

Outcomes or Projected Impacts

• Increased production efficiency.
• Reduced animal stress and mortality.
• Improved supplemental nutrition for birds.
• Reduction in poultry house diseases.
• Improved well-being for the birds.

Milestones

(1999): <LI>Collect data on thermoregulation and local heat loss. <LI>Collect data on ammonia release. <LI>Test infrared ammonia sensing system in production-scale setting. <LI>Evaluate light sources for effects on production and consumption. <LI>Design lysine diets and nutritional analysis protocol (turkeys)

(2000): <LI>Continue to collect data sets (see above). <LI>Test carbon/bicarbonate buffer systems for CO2 partitioning. <LI>Monitor Salmonella in turkey litter and houses, as affected by diet. <LI>Evaluate economics of lighting strategies.

(2001): <LI>Continue data collection (see above). <LI>Construct model of biological regulatory control loops for carbon. <LI>Construct model of ammonia release and water delivery systems.

(2002): <LI>Continue data collection (see above). <LI>Evaluate models of appropriate technologies. <LI>Validate models developed.

(2003): <LI>Adapt models to user-friendly?status. <LI>Verify results of models. <LI>Interface models with simplified strategies and micro-controllers. <LI>Work with extension counterparts on technology transfer.

Projected Participation

View Appendix E: Participation

Outreach Plan

Organization/Governance

standard

Literature Cited

Attachments

Land Grant Participating States/Institutions

CT, DE, IA, IL, MD, MN, NE, PA, TX

Non Land Grant Participating States/Institutions

Producer, Spain