Brief Summary of Minutes of Annual Meeting

Steven R. Alm (stevealm@uri.edu) - University of Rhode Island;
Paul Backman (pbackman@psu.edu) - Pennsylvania Agricultural Experiment Station;
Mark J. Carroll (mc92@umail.umd.edu) - University of Maryland;
J. Marshall Clark (jclark@ent.umass.edu) - University of Massachusetts;
Bruce B. Clarke (clarke@aesop.rutgers.edu) - Rutgers University;
Richard S. Cowles (rcowles@caes.state.ct.us) - Connecticut Agricultural Experiment Station;
J. Scott Ebdon (sebdon@pssci.umass.edu) - University of Massachusetts;
Steven Fales;
Karl Guillard (karl.guillard@uconn.edu) - University of Connecticut;
Richard J. Hull (rhu6441@postoffice.uri.edu) - University of Rhode Island;
Noel Jackson;
Peter J. Landschoot (pj11@psu.edu) - The Pennsylvania State University;
Pim Larsson-Kovach (il11@cornell.edu) - Cornell University;
James Lin - USEPA;
Bill Meyer (wmeyer@aesop.rutgers.edu) - Rutgers University;
Kevin Morris - NTEP;
Bridget Ruemmele (bridgetr@uri.edu) - University of Rhode Island;
Mike Sullivan (senmike@uriacc.uri.edu) - University of Rhode Island;
Patricia Vittum (pvittum@ent.umass.edu) - University of Massachusetts

Increased Comprehension and Quantification of Avian Behavior

At MD a study explored broiler behavior relative to perch availability, stocking density, aggression and immune status. Frequency of perching increased with stocking density and aggression decreased with stocking density. The most aggressive behavior occurred in the treatment without perches and the least in a horizontal perch treatment. Aggression increased in angled perch treatments. Aggression and perching behavior increased with age until 3 to 4 weeks and decreased to low levels at the end of the flock. In a trial with and without horizontal perches, higher densities increased bursa weight and bursa/body weight ratios decreased significantly (P <0.05). Addition of perches to the pens also significantly decreased the bursa weights and bursa/body weight index (P<0.01) and the stimulation index (blastogenesis assay) from 4 weeks to 6 weeks of age dropped dramatically (P<0.01). Bursal weight was found to be the best indicator of stress related to housing density

Mathematical Modeling

Operations research methods for optimizing broiler production were investigaed at PA. It was found that a successful application systems analysis to optimize production and products was reported for the Brazilian company, Sadia Concordia SA ( Taube-Netto, 1996. INFORMS 26:38-53). This is a pioneering example that shows how the variability of production can be used to meet the weight ranges of poultry products. Other PA studies investigated the number of days of growth velocity needed to detect pulmonary hypertension syndrome in broilers, the use of multiple objective programming to meet the goals of feed formulation, and the prediction of metabolizable energy using linear regression and artificial neural networks.
To further the establishment of databases useful in modeling activities, MI studied the use of
a computerized weighing and recording system for obtaining live turkey bodyweights dynamically over an entire growout period. Relatively high precision bodyweight parameters were obtained without the labor intensive and arduous task or disruptive and bird injury problems that usually accompany manual bird handling weighing procedures.

Nutritional Impacts on Turkey Growth and Carcass Yields

A study to ascertain if turkey breast meat yields in male market turkeys could be enhanced by varying methionine (TSAA) levels and supplementing betaine under a !‘clean!( or !‘dirty!( barn environment was conducted at MN. No differences in body weights among diets were found at the end of the trial, but the percentage breast meat yield and amount of breast meat was affected by diet. Methionine additions tended to improve percentage breast meat yields, but betaine had an even greater effect, significantly improving yield at each tested methionine addition.

In a second study, MN looked at the effect of corn fatty acids -- a high oleic acid corn and control corn variety-- on the carcass quality of market turkeys. Fatty acid content of the carcass fat pad, meat shelf-life and consumer preference were the specific carcass quality attributes evaluated. Inclusion of a high oleic acid corn in the diets was found to have a positive effect on organoleptic traits of breast meat and also delayed the development of rancidity in material stored cooked or uncooked. The high oleic acid corn was particularly effective in delaying development of rancidity in cooked and uncooked breast meat and in uncooked thigh meat.

Physiological mechanisms of thermoregulation, impacts of heat stress on thermoregulation and the development of techniques for minimizing the adverse aspects of heat stress
Studies at IA, MD and NE were conducted in this subject matter focus area. In collaboration with KY and NE, IA led an effort to determine the cooling water needs of laying hens cooled by partial surface (head and appendages) wetting. A new, surgery-free telemetric system for body temperature measurement was explored in this study and positive results were revealed. This system provides an improved, non-invasive way to quantify physiological responses of poultry to thermal stressors. The expected outcome of this study includes a) quantification of cooling water application rate as a function of air temperature, vapor pressure deficit (VPD), and air velocity that can be used for development of an intelligent controller; b) quantification of cooling efficacy of the partial surface wetting at various thermal conditions; and c) development of thermal discomfort index for laying hens that incorporate the effects of the aforementioned physical factors.

In collaboration with KY, IA has developed and tested a unique measurement and control system for characterizing dynamic feeding and drinking behavior of individual poultry. Using this system, the effects of cool (18aC or 65aF) vs. warm (27aC or 80aF) drinking water on laying hens subjected to warm conditions (27 to 35 aC or 80 to 95aF; 45 to 60% RH) were quantified. The cooler drinking water was shown to be more conducive to the hen performance under the testing conditions. The result suggests a potential viable means for the egg industry to sustain bird well-being and production efficiency during the adverse weather periods.
At MD, broiler chicks were exposed to three perch treatments to determine preferences for water-cooled over ambient temperature perches, and whether there were preferences for height, location and temperature section of the perch. The experimental treatments were: 1) three cool perches 15 cm above the floor (Cool 15), 2) three ambient perches 7.5 cm off the floor (Ambient 7.5), 3) three ambient perches 15 cm high (Ambient 15) and 4) control chambers with no perches. The total number of birds perching, their position, and temperature section within the perch were recorded. Results indicate a strong preference for high perches as birds grow (P<0.001). The cooler sections of the perch were utilized more than warmer sections within the cool treatments (P<0.05). Females showed a stronger tendency to use the perches than males, particularly within the cool treatment (P <0.0001). The higher perch use could be one of the reasons for the higher eviscerated body weight found in females with access to cool perches (P<0.05). Differences in mean body weight approached significance (P = 0.07), being higher for the birds with access to the cool perches suggesting that providing broiler chickens with access to cool perches can be a means of reducing heat stress and improving body weight during periods of high ambient temperature. Also, MD continues to collaborate with NE in developing temperature-humidity indexes for young meat chickens.
Three studies conducted at NE focused on physiological mechanisms. The objective of the first study was to determine, in avian species (Gallus domesticus), whether a link exists between heat stress and progesterone (P4) via the induction of IL-1R. Controlled studies were then conducted to 1. determine the effects of in vitro incubations of granulosa cells from HS hens with IL-1R; and 2. ascertain the effect of HS and IL-1R on 3B-HSD (3B-hydroxysteroid-dehydrogenase), the enzyme responsible for converting pregnenolone to P4. It was found that both HS and incubation with IL-1R depress P4 production by GC of laying hens. In addition, activity of 3R-HSD was reduced by both treatments and the vacuolar appearance of cells in both culture environments is similar. Thus, it appears that IL-1R can mimic the effect of HS on in vitro P4 production, at least partially through disruption of steroidogenesis as suggested by the decreased activity of 3R-HSD, the enzyme that converts pregnenolone to P4. The second study was designed to test the hypothesis that HS-induced reduction in T3 in birds acts as a functional hypothyroidism with regard to the reproductive process and that at least part of this effect is caused, as it appears to be in mammals, by elevated VIP. In both Hy and HS brains, the numbers of VIP-ir cells were increased over the Co. Adding thiouracil to the diet reversed the effect of Hy, in that numbers of VIP-ir cells were not different from Co, but were clearly lower than either Hy or HS. These observations suggest that HS disrupts reproduction in the hen, al least in part, via thyroid action on VIP !V a mechanism similar to that indicated for mammals. The third study was conducted to determine, for the three commercial laying hen varieties, the production, hormonal or metabolic responses that occurred during heat stress (HS) using both production and calorimeter settings. The study, among other things, confirmed that total heat loads are more lethal to the bigger and heavier birds. This calorimeter study is the first to examine the heat production characteristics of different strains of hens in relation to their responses in production settings.

Poultry Health Enhancement

Studies were conducted at TX to develop a method of measuring thrombocyte aggregation and to use this technique to investigate the effects of incidence of pulmonary hypertension syndrome (PHS) in the broiler chicken. Broilers were reared either under hypobaric conditions (simulated altitude 2900 m) to induce PHS or under normobaric conditions (altitude 96.7 m) for a period of five weeks. Compared to normobaric broilers, hypobaric broilers had lower body weights, increased hematocrit levels, and greater right ventricular weight to total ventricular weight ratio as a hypertrophy index measurment and increased PHS mortality compared to the broilers reared in normobaric conditions. Also, compared to normobaric broilers, hypobaric broilers produced less nitric oxide in the right pulmonary artery, significant after four weeks of hypobaric exposure. The thrombocyte counts were reduced in the hypobaric broilers at four and five weeks of age. There were no consistent differences in whole blood or thrombocyte-rich plasma aggregation between the environment group. Finally, changes in the rate of thrombocyte aggregation do not seem to be correlated with these results nor with the development of PHS in the broiler chicken.

A high passage attenuated R strain of M. gallisepticum is being tested as a modified live vaccine for the prevention of M. gallisepticum disease and as a vector for the delivery of genes encoding protective antigens from bacterial and viral avian pathogens at CT. Study results suggest that R-high and another strain (GT-5) are promising live attenuated strains of M. gallisepticum that may be appropriate as a vaccine strain. In addition, the R-high strain may be useful as an expression vector based upon the serological response of chickens immunized with a single close transform of the R-high strain.

Poultry Housing Environments and Environmental Impacts

A proposal for a pilot project to investigate the use of plastic optical fiber (POF) cables to illuminate poultry facilities has been initiated by CT and funded by the Connecticut Poultry Association. POF cables will be placed in individual cages and a single illuminating source will be utilized. This light source is rampable and filterable to deliver the exact level and frequency of illumination to the birds. The use of fiber optics may enhance egg production in cage layers by providing more precise and even lighting and enhance the energy efficiency of lighting caged laying hens.
In collaboration with AR and KY, IA took the lead in updating the heat and moisture production rates (HP, MP) of poultry and their housing environment. A comprehensive review of the literature on poultry HP and MP for the past 50 years has been completed. Quantification of broiler HP and MP in modern commercial production settings has been performed. Measurement of pullet and laying hen HP and MP is currently in progress. The new data will lead to more efficient design and operation of the building ventilation system, thus improved indoor air quality and production efficiency. The data also represents the advancement in scientific knowledge.

In a study to evaluate the efficacy of products to inhibit ammonia production, IL researchers compared ammonia generation rates from hen manure that received an ammonia production inhibitor that worked systemically (through the feed) to a topically applied compound. Mean overall mass generation rate of ammonia (mgNH3/hr/kg manure) for the two week period of manure collection was 58, 52, and 31 for the Control, Systemic, and Topical treatments, respectively. Ammonia generation rate from manure collection ages of day-1, week-1, and week-2 was lower for the Topical treatment. Treatments had no affect on fecal weight or moisture; However when ammonia generation rate was compared on a dry weight basis for the week-2 evaluation, the Systemic and Topical treatments were lower (17 and 26 %, respectively) than the Control.

Another IL study was conducted to determine the degree of leaching of nitrogen and phosphorus, and permeability of soils from earthen floors within several turkey barns.The results indicated that significantly greater concentration of total Kjeldahl nitrogen (TKN) were present in the first 3 ft. of soil depth for the inside vs outside (control) samples for all farms. However, no differences in total Kjeldahl nitrogen (TKN) concentration were found between inside and outside samples for the 4- and 5-ft. deep samples. For nitrate nitrogen (NO3-N), concentrations were greater for inside vs outside samples at the first 3 ft. of depth, and 5 ft. depth for all farms. Total phosphorus (P2) concentrations were essentially the same between inside vs outside samples for depths 2-5 ft. This indicated that total phosphorus (P2) did not migrate in the soil. The soil permeability results indicated that lower permeability occurred for the inside vs outside samples at the 1-3" and 5-7" depths for all farms averaged together. This study suggests that even though some soil nutrients leached below the surface of the ground inside a turkey facility, leaching essentially stopped at the 4 to 5 ft. level. In addition, the degree of soil permeability may be lowered by the presence of turkeys grown inside a facility. Thus, it is highly unlikely that subsurface ground water would ever be contaminated by harmful soil nutrients.

Work attempting to define the relationship between total litter moisture and litter water activity was continued in MD. Litter water activity and total litter moisture under field conditions from 216 litter samples were collected over a 12 month period. A scatter gram plot of total litter moisture vs. litter water activity shows a non-linear relationship. Another MD study was undertaken to better define the impact of litter/manure ventilation, water activity, and total litter moisture on Salmonella and E. coli loads on poultry farms. Results from 86 poultry production houses showed that airflow rates > 60 ft/min. may be important in maintaining drier litter/manure conditions and the drier conditions created an adverse environment for the growth and multiplication of the pathogenic organisms investigated.
Revision and Development of Web Publication of the Handbook "Biomeasurements and Experimental Techniques for Avian Species"

Further evolutionary progress was made !Vwith editorship spearheaded by members from Paul Harrison (IL) and Lewis Carr (MD) and web publishing activities by Michael Darre (CT)-- among participating stations and CSREES, to revise and publish on the world wide web the handbook !‘Biomeasurements and Experimental Techniques for Avian Species!( that was an initial publication hallmark of the original NE-127 Committee. With $3,500 of seed money support for web site development approved and allocated by the NE Multi-State Research Committee Directors, Michael Darre is in the process of hiring an individual possessing the appropriate skills. As soon as the web site construction is completed, the Universal Resource Locator (URL) will be widely disseminated.

CONNECTICUT

• Bell, D.D., P. H. Patterson, K. W. Koelkebeck, K. E. Anderson, M. J. Darre, J. B. Carey and G. Zeidler. Egg Marketing in National Supermarkets: Egg Quality - Part 1. Part 1. Poultry Sci. 79:(In press).
  
• Patterson, P.H., K. W. Koelkebeck, D. D. Bell, J. B. Carey, K. E. Anderson and M. J. Darre. Egg Marketing in National Supermarkets: Speciality Eggs - Part 2. Poultry Sci. 79:(In press).
  
• Koelkebeck, K.W., D. D. Bell, J. B. Carey, K. E. Anderson and M. J. Darre. Egg Marketing in National Supermarkets: Products, Packaging, and Prices - Part 3. Poultry Sci. 79:(In press).
  

ILLINOIS

• Bell, D. D., P. A. Patterson, K. W. Koelkebeck, K. E. Anderson, M. J. Darre, J. B. Carey, D. R. Kuney, and G. Zeidler, 2000. Egg marketing in national supermarkets: Egg quality - Part 1. Poultry Sci. 79:(In press).
  
• Boling, S. D., M. W. Douglas, M. L. Johnson, X. Wang, C. M. Parsons, K. W. Koelkebeck, and R. A. Zimmerman, 2000. The effects of dietary available phosphorus levels and phytase on performance of young and older laying hens. Poultry Sci. 79:224-230.
  
• Boling, S. D., M. W. Douglas, R. B. Shirley, C. M. Parsons, and K. W. Koelkebeck, 2000. The effects of various dietary levels of phytase and available phosphorus on performance of laying hens. Poultry Sci. 79:(In press).
  
• Koelkebeck, K. W., 2000. A study on the degree of permeability and leaching of nitrogen, phosphorus, and potassium in soils within turkey barns. Poultry Sci. 79(Suppl. 1):8.
  
• Koelkebeck, K. W., D. D. Bell, J. B. Carey, K. E. Anderson, and M. J. Darre, 2000. Egg marketing in national supermarkets: Products, packaging, and prices - Part 3. Poultry Sci. 79:(In press).
  
• Koelkebeck, K. W., C. M. Parsons, M. Douglas, R. W. Leeper, S. Jin, X. Wang, Y. Zhang, and S. Fernandez, 2000. Early postmolt performance of lyaing hens fed a low-rpotein corn molt diet supplemented with spent hen meal. Poultry Science 79:(In press).
  
• Makled, M. N., K. W. Koelkebeck, C. M. Parsons, and A. B. Corless, 2000. Effect of acute and cyclic heat stress on amino acid digestibility of four feedstuffs. 21st Worlds Poultry Congress. (In press.)
  
• Patterson, P. H., K. W. Koelkebeck, D. D. Bell, M. J. Darre, J. B. Carey, and K. E. Anderson, 2000. Egg marketing in national supermarkets: Speciality eggs - Part 2. Poultry Sci. 79:(In press).
  

IOWA

• Chepete, H.J. and H. Xin. 2000. Alleviating heat stress of laying hens by intermittent partial surface cooling. Transactions of the ASAE 43(4): 965-971.
  
• Chepete, H. J. and H. Xin. 2001. Heat and moisture production of poultry their housing systems  Review of literature. Proc of the Sixth International Livestock Environment Symposium, May 21-23, 2001, Louisville, KY. Published by ASAE, St. Joseph, MI.
  
• Han, T. and H. Xin. 2000. Effects of intermittent lighting on limited-fed neonatal chicks. Transactions of the ASAE 43(6):
  
• Ikeguchi, A. and H. Xin. 2000. Field evaluation of a sprinkling system for cooling commercial laying hens in the Midwestern U.S. region. Applied Engineering in Agriculture (In press).
  
• Puma, M.C., H. Xin, R.S. Gates, and D. J. Burnham. 2000. An instrumentation system for measuring feeding and drinking behavior of poultry. Applied Engineering in Agriculture (In press).
  
• Xin, H., I.L. Berry, and T.A. Costello. 2001. Heat and moisture production of broiler chickens in commercial housing. Proc of the Sixth International Livestock Environment Symposium, May 21-23, 2001, Louisville, KY. Published by ASAE, St. Joseph, MI.
  
• Yang, P., J.C. Lorimor, and H. Xin. 2000. Nitrogen loss from laying hen manure in high-rise layer houses. Applied Engineering in Agriculture 16(6): 1771-1780.
  

MARYLAND

• deGraft-Hanson, J. A., L. E. Carr and V. E. Byrd. 2000. Effect of Moisture and Water Activity on the Presence of Salmonella in Broiler Litter. Poultry Science (Supplement 1) - 91.
  
• deRezende, C. L., E. T. Mallinson, N. L. Tablante, R. Morales, A. Park, L. E. Carr and S. W. Joseph. 2000. The Effect of Dry Litter and Airflow in Reducing Salmonella and E. coli Populations in the Broiler Production Environment. Applied Poultry Research (in press).
  
• Estevez, I; N. Tablante, R. Pettit-Riley, and L. Carr, 2000. Use of cool perches by broiler chickens. Submitted to Poultry Science.
  
• Estevez, I. and R. Pettit-Riley, 2000. Effects of density on the use of perches in broilers. Poultry Science, vol.79 (supplement 1): 36.
  
• Hayes, J. R., L.E. Carr, E. T. Mallinson, L. W. Douglass and S. W. Joseph. 2000. Characterization of the Contribution of Water Activity and Moisture Content to the Population Distribution of Salmonella Spp. In Commercial Poultry Houses. Poultry Science 79: 1557-1561.
  
• Heckert, R. A.; I. Estevez, E. Russek-Cohen and R. Pettit-Riley, 2000. Effects of density, heat stress and perch availability on the immune status of broilers. Submitted to Poultry Science.
  
• Mallinson, E. T., C. E. deRezende, N. L. Tablante, L. E. Carr and S. W. Joseph. 2000. A Management Technique to Identify Prime Locations of Salmonella Contamination on Broiler and Layer Farms. Applied Poultry Research 9(3): 364-370.
  
• Okelo, P. O. 1999. Effectiveness of Using a Cool Perch System or Cool and Carbonated Drinking Water to Relieve Heat Stress in Broilers. Unpublished MS Thesis, University of Maryland.
  
• Pettit-Riley, R. and I. Estevez, 2000. Effects of density on perching behavior of broiler chickens. Applied Animal Behaviour Science. (In press).
  
• Pettit-Riley, R., I. Estevez, , and E. Russek-Cohen, 2000. Effects of stocking density and access to perches on aggressive behaviour in broilers. Submitted to Applied Animal Behaviour Science.
  
• Pettit, R. 2000. Effects of perch availability and stocking density on perching behavior and aggression in broiler chickens. Master Thesis, University of Maryland.
  

MINNESOTA

• Erf, G. F., S. Noll, T. K. Bersi, X. Wang, J. Kalbfleisch, and W. G. Bottje, 2000. Effects of dietary Vitamin E supplementation in young male turkey poults: 2. Tissue Levels of Vitamin E, proportions and concentrations of immune cells. Poultry Sci. 79 (Supplement 1): 117.
  
• Ergul, T., S. L. Noll, J. Brannon and M. I. Endres, 2000. The effect of high oleic acid corn in turkey diets: 1. Turkey tom performance. Poultry Sci. 79 (Supplement 1): 30.
  
• Ergul, T., P. B. Addis, S. L. Noll, and M. I. Endres, 2000. The effect of high oleic acid corn in turkey diets: 2. Meat sensor evaluation and rancidity development in thigh and breast muscle. Poultry Sci. 79 (Supplement 1): 26.
  
• Halvorson, D., K. V. Nagaraja, , D. P. Shaw, M. K. Njenga, S. Goyal, and S. Noll, 2000. Control of Viral Respiratory Diseases of Turkeys. Gobbles 57 (8):6, Minnesota Turkey Growers Association, St. Paul, MN.
  
• Jirjis, F. F., S. L. Noll, D. A. Halvorson, K. V. Nagaraja, E. L. Townsend, A. M. Sheikh, and D. P. Shaw, 2000. Avian Pneumovirus Infection in Minnesota Turkeys: Experimental Reproduction of the Disease. Avian Diseases 44:222-226.
  
• Jirjis, F. F., S. L. Noll, D. A. Halvorson, K. V. Nagaraja, and D. P. Shaw, 2000. Minimum Infectious Dose of Avian Pneumovirus in Turkeys. Poultry Sci. 79 (Supplement 1): 23.
  
• Kalbfleisch, J., S. Noll, V. Stangeland, G. Speers, and J. Brannon, 2000. Amino acid and energy responses of male market turkeys: 2. Methionine and betaine responses by turkeys in clean or dirty environments. Poultry Sci. 79 (Supplement 1): 26.
  
• Kalbfleisch, J., G. F. Erf, S. Noll, and J. Brannon, 2000. Effects of dietary Vitamin E supplementation in young male turkey poults: 1. Growth Performance and Lymphoid organ Characteristics. Poultry Sci. 79 (Supplement 1): 116.
  
• Noll, S. L., 2000. Nutritional Influences on Meat Quality in Poultry. Proceedings "61st Minnesota Nutrition Conference", Pages 215-224. University of Minnesota, St. Paul, MN.
  
• Noll, S. L., V. Stangeland, G. Speers, and J. Brannon, 2000. Amino acid and energy responses of male market turkeys: 1. Energy to amino acid ratio in mash and pelleted feed and influence of feed additives. Poultry Sci. 79 (Supplement 1): 55.
  
• Shaw, D., S. Noll, F. Jirjis, D. Halvorson, K. V. Nagaraja, S. Goyal, M. K. Njenga and K. A. Janni, 2000. Pathogenesis of Avian Pneumovirus Infection of Turkeys. Gobbles 57(8):22, Minnesota Turkey Growers Association, St. Paul, MN.
  
• Stangeland, V., S. Noll, J. Brannon, and J. Kalbfleisch, 2000. Methionine and Betaine in Diets for Market Toms. Gobbles 57(8):18, Minnesota Turkey Growers Association, St. Paul, MN.
  
• Waibel, P. E., C. W. Carlson, J. A. Brannon, and S. L. Noll, 2000. Limiting Amino Acids after Methionine and Lysine with Growing Turkeys Fed Low-Protein Diets. Poultry Sci. 78:1290-1298.
  
• Waibel, P. E., C. W. Carlson, J. A. Brannon, and S. L. Noll, 2000. Identification of Limiting Amino Acids in Methionine- and Lysine-Supplemented Low-Protein Diets for Turkeys. Poultry Sci. 78:1299-1305.
  

NEBRASKA

• Alodan, M.A. and M.M. Beck, 2000. IL-1 suppresses progesterone production in vitro by granulosa cells of laying hens. Poultry Sci. 79(suppl):50.
  
• Beck, M.M. and S.A. Elnagar, 2000. VIP-immunoreactive cells increase in hypothalamic nucleus of heat-stressed and hypothyroid hens. Poultry Sci. 79(suppl):78.
  
• Bridger, J. L. Robeson, D. Franco, and M.Beck, 2000. Metabolic and production responses of three laying hen varieties to heat stress. Poultry Sci. 79(suppl):79.
  
• Elnagar, S.A. Thyroid hormones and reproduction in the laying hen. PhD Dissertation, University of Alexandria, Alexandria, Egypt.
  
• Elnagar, S.A. and M.M.Beck, 2000. Heat-induced hypothyroidism mediates changes in reproductive hormones in laying hens. Poultry Sci. 79 (suppl):99.
  
• Elston, J.J., M.M.Beck, S.D.Kachman and S.E. Scheideler, 2000. Laying hen behavior 1. Effects of cage type and startle stimulus. Poultry Sci. 79:471-476. (ARD 12499)
  
• Elston, J.J., M.M. Beck, M.A. Alodan, and V. Vega-Murillo, 2000 Laying hen behavior: 2. Cage type preference and heterophil:lymphocyte ratio. Poultry Sci. 79:477-482. (ARD 12529)
  
• Franzen, K.K., D. Clopton, and M.M. Beck, 2000. Endocrine reproductive properties in the laying hen change with age. Poultry Sci. 79(suppl):56.
  
• Teruyama, R. and M.M. Beck, 2000. Changes in immunoreactivity to anti-cGnRH-I and II are associated with photostimulated sexual status in male quail. Cell and Tissue Res. 300:413-426.(ARD 12234).
  
• Teruyama, R. and M.M. Beck, Double immunocytochemistry of VIP and cGnRH-I in quail brain: photoperiodic effects. (ARD 12414). Cell and Tissue Research.:(In press).
  

PENNSYLVANIA

• Kliger, C. A., A. S. Gehad, R. M. Hulet, W. B. Roush, H. S. Lillehoj, M. M. Mashaly, 2000. Photoperiod and melatonin and their effects on lymphocyte activities in male broiler chickens. Poultry Sci. 79:18-25.
  
• Roush, W.B. and R.F. Wideman, Jr., 2000. Evaluation of broiler growth velocity and acceleration in relation to pulmonary hypertension syndrome. Poultry Science 79:180-191.
  

TEXAS

• Martinez-Lemus, L. A., Miller, M. W., Jeffrey, J. S., and Odom, T. W. Echocardiographic Monitoring in Heart Function in Broilers Exposed to Normobaric or Hypobaric Conditions. Avian Disease 44:74-84, 2000.