@article{chichlowski_croom_mcbride_daniel_davis_koci_2007, title={Direct-fed microbial PrimaLac and salinomycin modulate whole-body and intestinal oxygen consumption and intestinal mucosal cytokine production in the broiler chick}, volume={86}, ISSN={["1525-3171"]}, DOI={10.1093/ps/86.6.1100}, abstractNote={The current study investigated whole-body O2 consumption, intestinal O2 consumption, and intestinal inflammation status through mucosal cytokine production on broiler chicks fed the direct-fed microbial PrimaLac. One hundred twenty 1-d-old broiler chicks were randomly assigned to 1 of 3 experimental diets: standard starter diet (control), standard starter diet with added salinomycin (SAL), and standard starter diet with added PrimaLac (DFM). Birds were housed in 2 separate rooms, the control and SAL treatments in one room and the DFM in another. Intact ileal and cecal samples were collected on d 19, 20, and 21 after measuring whole-body O2 consumption using indirect calorimetry. The O2 up-take of ileal tissue was measured using an in vitro O2 monitor. Analysis of intestinal immune status of broilers was measured by the relative differences in mRNA of both pro- and antiinflammatory cytokines: interleukin-(IL) 1beta, IL-6, and IL-10 using real-time reverse transcription-PCR. Broilers exhibited a 6 to 16% decrease in whole-body energy expenditures and up to a 47% decrease (P<0.05) in ileal energy expenditures in the DFM group compared with other treatments. The reverse transcription-PCR data demonstrated that DFM consortium numerically altered both pro- and antiinflammatory cytokines within the ileum of 19-d posthatch broilers. These data suggest that direct-fed microbials like PrimaLac increase metabolic efficiency via changes in intestinal physiology and metabolism.}, number={6}, journal={POULTRY SCIENCE}, author={Chichlowski, M. and Croom, J. and McBride, B. W. and Daniel, L. and Davis, G. and Koci, M. D.}, year={2007}, month={Jun}, pages={1100–1106} } @article{anderson_jones_davis_jenkins_2007, title={Effects of genetic selection on behavioral profiles of single comb white Leghorn hens through two production cycles}, volume={86}, ISSN={["1525-3171"]}, DOI={10.1093/ps/86.9.1814}, abstractNote={Four layer genetic stocks consisting of 3 Ottawa control strains (5, 7, and 10) and a commercial laying stock (CCS) were utilized to evaluate potential changes in behavioral profiles due to the effects of genetic selection through 2 production cycles. The Ottawa strains were started as random bred strains from the crosses of several popular commercial layers in 1950, 1959, and 1972, and the commercial strain used herein was from calendar year 1993, and its ancestors were involved in the formation of all of the random bred strains. The behavior study utilized 2 replicates from each strain that contained 4 cages, 6 hens/cage, for a total of 192 hens. Behavioral observations were recorded on 2 consecutive days beginning at 22 wk of age and every 28 d thereafter during the first production cycle, the molt period, and the second production cycle through 90 wk of age and periodic feather and Hansen's test scores recorded. Behavior profiles were similar between the control strains and the CCS, indicating that long-term genetic selection by commercial egg-type breeding firms to enhance production parameters has had no impact on laying strain behavior patterns. Appetitive behaviors were not affected by strain. During the molt, hens had reduced (P < 0.05) feeding and drinking frequencies in comparison with those observed during the first and second cycles. The data indicated that hens pecked inedible objects at a greater (P < 0.0001) frequency during the first cycle and molt than during the second cycle. Fearfulness scores were only influenced by production phase with the molt having the highest (P < 0.01) score of 3.46. Strain or production phase did not influence the frequency of aggressive and submissive acts.}, number={9}, journal={POULTRY SCIENCE}, author={Anderson, K. E. and Jones, D. R. and Davis, G. S. and Jenkins, P. K.}, year={2007}, month={Sep}, pages={1814–1820} } @article{anderson_davis_jenkins_carroll_2004, title={Effects of bird age, density, and molt on behavioral profiles of two commercial layer strains in cages}, volume={83}, ISSN={["0032-5791"]}, DOI={10.1093/ps/83.1.15}, abstractNote={Two commercial strains, Hy-Line W-36 and DeKalb XL, were moved to a laying house at 18 wk of age. They were housed 6 hens/layer cage at 2 densities (361 and 482 cm2/bird) with 2 replications each per strain/density combination. The high-density treatment contained 24 hens/replication and the low-density treatment contained 18 hens/replication for a total of 168 hens. Production parameters were measured during the first egg production cycle, the molt period, and the first 4 wk of the second lay cycle (20 to 68 wk of age). Behavioral observations were taken during 2 consecutive d at 26, 34, 43, 51, 62, 64, and 68 wk of age to examine behavioral patterns. Modified Hansen's tests were conducted concurrently to provide indication of the fearfulness levels of hens at the various stages of production. The production characteristics were similar for both strains. The hens kept at the higher density had lower (P < 0.01) hen-day production and (P < 0.05) daily egg mass. Appetitive behaviors were not affected by strain or density but were affected by the age of the hen and by molting. During the molt, feeding and drinking behavioral acts were fewer (P < 0.05) at 0.018 and 0.013 acts per bird/min, respectively, and standing behavior was highest. The results indicated that the frequencies of pecking inedible objects during the molt period were similar to the frequencies at 26 and 34 wk. Hens performed more acts of standing, and crouching and had lower frequency of movement during the molt. Those kept at a low density performed more movement acts. Feather pecking decreased as hens aged and increased when they molted but was not affected by strain or density. The frequency of aggression and submissive acts was significantly lower during the molt period. Behaviors were affected by strain, density, bird age, and molting; however, the patterns and number of aggressive acts did not increase to compromise the welfare status of the hens. Behaviors during the molt appeared consistent with mechanisms for conservation of body reserves.}, number={1}, journal={POULTRY SCIENCE}, author={Anderson, KE and Davis, GS and Jenkins, PK and Carroll, AS}, year={2004}, month={Jan}, pages={15–23} } @article{christensen_davis_2004, title={Maternal dietary iodide influences turkey embryo thyroid function}, volume={3}, ISBN={1682-8356}, DOI={10.3923/ijps.2004.550.557}, abstractNote={An experiment was designed to examine a mechanism to improve embryonic survival following maternal thyroid hormone manipulation. Commercial turkey breeder hens were fed diets containing supplemental iodide to mimic changes in the maternal thyroid output during an egg production cycle (32 to 48 wk of age). Dietary iodide treatment depressed maternal blood thyroxine (T4) concentrations in a time-dependent manner. Dietary iodide depressed maternal blood 3, 5, 3'-triiodothyronine (T3) levels across all times examined. The maternal dietary treatment increased embryonic blood concentrations of T4 at 25 to 28 d of incubation but depressed blood concentrations of T3 only at 27 d of incubation. In a second trial, the same response was noted in maternal blood when the hens were fed additional iodide with no corresponding effects on T3 concentrations. The iodide treatment decreased embryonic T4 concentrations in the second trial as well but in a time-dependent manner. Iodide accelerated the increase in T4 concentrations coincidental with earlier pipping in eggs from iodide-fed dams compared with controls. The data indicate that the embryonic thyroid function during hatching is dependent upon the maternal thyroid in turkey dams, even though the embryo develops outside the maternal body.}, number={9}, journal={International Journal of Poultry Science}, author={Christensen, V. L. and Davis, G. S.}, year={2004}, pages={550} } @article{davis_anderson_jones_2004, title={The effects of different beak trimming techniques on plasma corticosterone and performance criteria in single comb White Leghorn hens}, volume={83}, ISSN={["1525-3171"]}, DOI={10.1093/ps/83.10.1624}, abstractNote={DeKalb XL chicks were given a beak trim at 6 d of age (6DP) with a 2.8-mm gauge and a beak trim at 11 wk (11WB) with a block cut approximately 2 mm anterior to the nasal openings. Corticosterone (CS) levels of the 6DP treatment were (P < or = 0.01) elevated above nontrimmed CS levels at 2 h posttrim; and BW and feed consumption (FC) of the 6DP were depressed until 8 wk of age. At 11 wk of age, CS of the 11WB treatment was (P < or = 0.02) elevated above controls at 1, 2, 8, and 5 wk posttrim. The 11WB treatment resulted in a decrease in FC and a reduction in BW at 12, 14, and 16 wk of age, whereas there were no differences among treatments in livability during the pullet phase. At 72 wk of age, FC of the nontrimmed controls was greater than both beak trimmed treatments, and both beak trimmed treatments had greater hen housed eggs, percentage hen day egg production, and percentage livability. Both beak trimmed treatments resulted in better egg income, feed cost per hen, and net income (NI). The 6DP and 11WB beak trim treatments resulted in an improvement of NI per hen of 1.48 dollars and 1.86 dollars, respectively. In addition, both beak trimmed treatments exhibited better feather score and Hansen's test (fearfulness). It was concluded that pullets and hens could adapt to the physiological stress of beak trimming and out perform, during a lay phase, controls whose beaks were not trimmed.}, number={10}, journal={POULTRY SCIENCE}, author={Davis, GS and Anderson, KE and Jones, DR}, year={2004}, month={Oct}, pages={1624–1628} } @article{christensen_grimes_wineland_davis_2003, title={Accelerating embryonic growth during incubation following prolonged egg storage 1. Embryonic livability}, volume={82}, ISSN={["0032-5791"]}, DOI={10.1093/ps/82.12.1863}, abstractNote={The hypothesis was proposed that shorter incubation periods and faster growth rates for long-stored eggs would improve embryonic survival and poult hatchling quality. Increased incubation temperatures were tested for their efficacy in improving embryonic livability in fertilized eggs stored for 15 d prior to setting in the incubator compared to controls stored for only 3 d. Two temperature treatments were applied. In experiment 1, a 37.8 degrees C set point for dry bulb temperature was used to accelerate development for the initial 2 wk compared to the controls at 37.5 degrees C. Following treatment, the accelerated embryos were returned to the same machine as the controls. In experiment 2, higher temperature exposure was only for the initial week of incubation. The temperature and storage treatments were in a completely random 2 x 2 factorial arrangement of treatments. At the completion of 28 d of incubation, survival rates of all treatments were determined by opening all nonhatching eggs to differentiate truly fertilized eggs from unfertilized. Hatchability was determined by dividing the total number of poults on a hatching tray by the number of fertilized eggs on a tray. Incubator trays were the experimental unit. Tissues were sampled in both experiments to verify treatment effects on growth and metabolism. Hatching times were observed at 4-h intervals during the actual hatching process beginning at 25 d of incubation. It was concluded that delayed growth and depressed metabolism of fertilized turkey eggs stored for 15 d can be compensated for by exposure to higher incubation temperatures for the initial 1 or 2 wk of incubation.}, number={12}, journal={POULTRY SCIENCE}, author={Christensen, VL and Grimes, JL and Wineland, MJ and Davis, GS}, year={2003}, month={Dec}, pages={1863–1868} } @article{christensen_grimes_wineland_davis_2003, title={Accelerating embryonic growth during incubation following prolonged egg storage 2. Embryonic growth and metabolism}, volume={82}, DOI={10.1093/ps/82.12.1869}, abstractNote={The hypothesis was proposed that the improved embryonic livability observed when higher incubation temperatures were imposed on eggs stored for 15 d prior to setting might have basis in energy metabolism. To test the hypothesis, fertilized turkey eggs were incubated either for the first 2 wk of development (experiment 1) or only the first week of development (experiment 2) at 37.8 degrees C compared with controls incubated at 37.5 degrees C. In both experiments, eggs were stored for either 15 or 3 d prior to setting. Viable embryos were selected randomly from each storage-by-incubation period treatment combination at 25 to 28 d of incubation and were sampled for blood, heart, and skeletal muscle tissues. Tissues were weighed and assayed subsequently for glucose or glycogen content. In experiment 2, the randomly selected embryos from each treatment combination were sampled at 7, 14, 21, and 28 d of incubation. Embryos at 7 and 14 d were assayed on a whole body basis, whereas at 21 and 28 d the bodies were dissected, and heart, liver, and skeletal muscle tissues were weighed and assayed for glycogen and lactate. Blood samples were collected between 25 and 28 d of incubation as in experiment 1 and assayed for glucose, creatine kinase, lactate dehydrogenase, and thyroid hormone concentrations. In both experiments, accelerated development was noted due to higher temperature and enhanced embryonic carbohydrate metabolism, and elevated thyroid hormone concentrations were observed compared with controls. It was concluded that a possible mechanism for the improved livability of faster growing embryos observed after prolonged egg storage might be due to better utilization of carbohydrate.}, number={12}, journal={Poultry Science}, author={Christensen, V. L. and Grimes, J. L. and Wineland, M. J. and Davis, G. S.}, year={2003}, pages={1869–1878} } @article{christensen_davis_nestor_2002, title={Environmental incubation factors influence embryonic thyroid hormones}, volume={81}, ISSN={["0032-5791"]}, DOI={10.1093/ps/81.4.442}, abstractNote={Thyroid hormone responses in embryonic avian species are of two types, developmental and metabolic. Many studies have characterized the developmental function of the turkey embryonic thyroid, but few have characterized the metabolic function. Therefore, the purpose of this study was to describe the response of turkey embryonic thyroid hormones to three environmental factors. We proposed that embryonic thyroids from different genetic backgrounds would respond differently to changes in maternal diet and incubation temperature. Lines of turkeys known to have different embryonic growth and survival were examined in the current study. These eggs differ in egg weight, eggshell conductance, hatchling weight and organ maturity at the time of hatching. Eggs were produced throughout a 20 wk laying period and embryos were sampled at monthly intervals. Half of the hens producing the eggs were fed additional iodide in their diets, then, subsequently, half of each dietary treatment and line combination were incubated at either 36.8 C or 37.5 C to prolong the incubation period. Embryos were sampled during the final week of incubation when thyroid hormones become elevated to effect maturation and survival functions in turkey embryos. Embryonic thyroxine (T4) and triiodothyronine (T3) levels were assayed by RIA and compared among the treatments. Line, diet, and incubation period interacted to affect the levels of T4, T3 and T3 to T4 ratios in the turkey embryonic during late incubation. It was concluded that environmental factors can affect circulating thyroid hormone levels in turkey embryos, thus affecting metabolic functions, and the possibility exists to manipulate these circulating levels using environmental incubation conditions to improve hatchability.}, number={4}, journal={POULTRY SCIENCE}, author={Christensen, VL and Davis, GS and Nestor, KE}, year={2002}, month={Apr}, pages={442–450} } @article{davis_anderson_2002, title={The effects of feeding the direct-fed microbial, PrimaLac, on growth parameters and egg production in Single Comb White Leghorn hens}, volume={81}, ISSN={["0032-5791"]}, DOI={10.1093/ps/81.6.755}, abstractNote={Two commercial strains of Single Comb White Leghorn hens, HyLine W-36 and DeKalb XL, were reared separately as pullet flocks in an enclosed, environmentally controlled brood-grow house with three banks of quad-deck cages (310 cm2 per bird). There were 1,800 hens of each strain, which were divided into two groups, control feed and a direct-fed microbial (DFM) feed treatment. During the pullet-rearing phase to 18 wk of age, the DeKalb birds had greater parameters of growth and overall feed cost than the HyLine birds. The overall feed cost of the DFM treatment was $0.02 per bird greater than controls. However, the DFM-treated feed improved the livability of the DeKalb birds by 2.68%. At 18 wk of age, 3,528 hens were transferred to an enclosed, mechanically ventilated layer house. The two strains were placed in two differently sized quad-deck layer cages with seven birds per cage; the cage sizes were 35.56 cm x 60.96 cm (2,267.73 cm2 or 310 cm2 per bird) and 14 cm x 32 cm (2,890.32 cm2 or 413 cm2 per bird). There were a total of 144 replications with each strain and DFM treatment combination made up of 36 replications equally divided between the high and low density cages. At 70 wk of age, hens receiving the DFM treatment exhibited greater mean egg weights (61.72 g) and percentages of extra large eggs (XLE, 52.06%) compared to that of controls (61.12 g and 48.98%, respectively). The treatment of 310 cm2/hen DFM produced the least (P < or = 0.05) large eggs; however, this treatment group produced the most (P < or = 0.05) XLE. The use of DFM resulted in a shift from smaller to larger eggs. Regardless of density, the DFM hens had lower (P < or = 0.05) feed cost (FC) compared to FC of the controls (a savings of $0.46/bird between the DFM and control in the 310 cm2 /hen treatment and a $0.83 savings/bird between the DFM and control in the 413 cm2/hen treatment). It was concluded that PrimaLac can improve egg size and lower feed costs, regardless of the bird density used in the present study.}, number={6}, journal={POULTRY SCIENCE}, author={Davis, GS and Anderson, KE}, year={2002}, month={Jun}, pages={755–759} } @article{christensen_davis_2001, title={Maternal dietary iodide influences turkey embryonic thyroid function}, volume={80}, DOI={10.1093/ps/80.9.1286}, abstractNote={Abstract An experiment was designed to examine a mechanism to improve embryonic survival following maternal thyroid hormone manipulation. Commercial turkey breeder hens were fed diets containing supplemental iodide to mimic changes in the maternal thyroid output during an egg production cycle (32 to 48 wk of age). Dietary iodide treatment depressed maternal blood thyroxine (T4) concentrations in a time-dependent manner. Dietary iodide depressed maternal blood 3, 5, 3’-triiodothyronine (T3) levels across all times examined. The maternal dietary treatment increased embryonic blood concentrations of T4 at 25 to 28 d of incubation but depressed blood concentrations of T3 only at 27 d of incubation. In a second trial, the same response was noted in maternal blood when the hens were fed additional iodide with no corresponding effects on T3 concentrations. The iodide treatment decreased embryonic T4 concentrations in the second trial as well but in a time-dependent manner. Iodide accelerated the increase in T4 concentrations coincidental with earlier pipping in eggs from iodide-fed dams compared with controls. The data indicate that the embryonic thyroid function during hatching is dependent upon the maternal thyroid in turkey dams, even though the embryo develops outside the maternal body.}, number={9}, journal={Poultry Science}, author={Christensen, V. L. and Davis, G. S.}, year={2001}, pages={1286–1292} } @article{jones_anderson_davis_2001, title={The effects of genetic selection on production parameters of single comb white leghorn hens}, volume={80}, ISSN={["0032-5791"]}, DOI={10.1093/ps/80.8.1139}, abstractNote={Four commercial table egg genetic stocks consisting of the Ottawa Control Strains 5, 7, and 10 (CS5, CS7, and CS10) and the 1993 H&N "Nick Chick" (CCS) were housed in the same environment and compared for production characteristics. These birds were housed in an environmentally controlled laying facility with trideck cages. Feed consumption, egg production, and mortality were monitored daily and compiled every 28 d. The study was conducted for two egg production cycles, including the molt period. Body weight was progressively lower for the more modern strains with CS5 being the heaviest and CCS maintaining the smallest body weight throughout the production periods. The CCS had the highest (P < 0.0001) hen-day production rate, which resulted in the greatest daily egg mass among the strains. The CCS consumed the greatest amount of feed and exhibited the highest gross egg income among the strains. We concluded that genetic selection has improved production parameters in commercial layers as determined by measurements in this study.}, number={8}, journal={POULTRY SCIENCE}, author={Jones, DR and Anderson, KE and Davis, GS}, year={2001}, month={Aug}, pages={1139–1143} } @article{davis_anderson_carroll_2000, title={The effects of long-term caging and molt of Single Comb White Leghorn hens on herterophil to lymphocyte ratios, corticosterone and thyroid hormones}, volume={79}, ISSN={["1525-3171"]}, DOI={10.1093/ps/79.4.514}, abstractNote={Two commercial strains of 18-wk-old Single Comb White Leghorn (SCWL) hens, HyLine W-36 and DeKalb XL, were housed six hens per cage in layer cages at two densities (361 and 482 cm2 per bird) with two replications each per strain and density combination. The high density treatment contained 24 hens per replication, and the low density treatment contained 18 hens per replication. Egg production was measured during the first egg production cycle, a molt (fast) period, and the first 4 wk of the second lay cycle (20 to 68 wk of age). Blood samples were obtained from six hens from each replicate in each strain and density combination (total of 48) at 20, 26, 34, 43, 51, 62, 64, and 68 wk of age. In addition, blood samples were obtained in a random order from hens in each cage, and the sequence of sampling was recorded (1 to 6). Blood smears were made, from which heterophil to lymphocyte ratios (H:L) were determined. Radioimmunoassays were conducted to determine levels of plasma corticosterone (CS), 3,5,3'-triiodothyronine (T3), and thyroxine (T4). The results indicated that strain did not affect percentage hen-day egg production (%HDP). Strain and cage density did not affect H:L, T3, T4, or CS. However, these parameters were affected by bird age, which was related to the egg production cycle. Plasma CS significantly (P < or = 0.001) increased during peak %HDP at 26 wk and 64 wk during the molt (fast), and H:L significantly (P < or = 0.001) increased during the molt (fast) at 64 wk. The sequence in which blood samples were obtained, from hens within a cage in sampling order, also increased plasma CS. The CS was significantly (P < or = 0.001) elevated in the third, fifth, and sixth hens from which blood samples were drawn. Plasma T3 and T4 changed during the production cycle. The T3 was significantly (P < or = 0.0001) depressed during peak egg production at 26 wk and during the molt (fast) at 64 wk when compared with the other time periods. Plasma T4 was depressed (P < or = 0.0001) at 51 wk and was elevated (P < or = 0.0001) at 64 wk during the molt (fast). The physiological and metabolic parameters of the different hen strains and cage densities were similar during egg production. However, CS, T3, T4, and H:L changed with age in relation to the egg production cycle. In addition, the physiological demands of peak egg production and molt (fast) appeared to be similar.}, number={4}, journal={POULTRY SCIENCE}, author={Davis, GS and Anderson, KE and Carroll, AS}, year={2000}, month={Apr}, pages={514–518} } @article{davis_anderson_parkhurst_rives_hagler_1994, title={Mycotoxins and Feed Refusal by Pekin Ducks}, volume={3}, ISSN={1056-6171}, url={http://dx.doi.org/10.1093/japr/3.2.190}, DOI={10.1093/japr/3.2.190}, abstractNote={Abstract High mortality occurred in two flocks of ducklings: 20% and 50% by 4 and 7 days of age, respectively. The feeds were found to contain 300 to 1176 ppb of deoxynivalenol (DON), 4.5 ppm of fumonisin, and 10 ppb of aflatoxin B1. No other mycotoxins were detected. Pathological analysis indicated that the ducklings were dehydrated with no feed in the gastrointestinal tract. Histopathology revealed no significant lesions. A necropsy diagnosis indicated a condition similar to starve-outs and feed refusal. An infectious cause of mortality was not suspected.}, number={2}, journal={Journal of Applied Poultry Research}, publisher={Elsevier BV}, author={Davis, G.S. and Anderson, K.E. and Parkhurst, C.R. and Rives, D.V. and Hagler, W.M.}, year={1994}, month={Jul}, pages={190–192} } @article{davis_parkhurst_brake_1993, title={Light intensity and sex ratio effects on egg production, egg quality characteristics, and fertility in breeder pekin ducks}, volume={72}, ISSN={["0032-5791"]}, DOI={10.3382/ps.0720023}, abstractNote={Abstract A flock of 520, 11-wk-old breeder Pekin ducklings was raised in 20 floor pens in a curtain-sided poultry house under decreasing day lengths. At 22 wk of age, the ducklings were photostimulated (16 h of light/day) with a combination of natural daylight and artificial light. After dusk, half of the ducklings were exposed to 10 lx of incandescent (IN) light and the other half were maintained under 172 lx of high-pressure sodium (HPS) light. In addition, each light treatment consisted of an equal number of pens with two different sex ratios, 22 hens:4 drakes (15% males) and 21 hens:5 drakes (19% males). Egg production, egg quality characteristics, and fertility were monitored from 22 to 52 wk of age. Ducklings housed under 172 lx of HPS light exhibited significantly (P ≤ .05) greater egg production between 23 and 34 wk of age. Egg weight, shell weight, and shell thickness were not consistently affected by the different light treatments or sex ratios. The sex ratios did not affect percentage egg fertility, but fertility was significantly (P ≤.05) higher in the HPS light treatment during the last 15 wk of the study. It was concluded that HPS light of 172 lx can enhance egg production in breeder Pekin ducklings prior to peak production (37 wk), and HPS light can improve fertility following the peak egg production period. Furthermore, this study indicated that a breeder duckling flock with 15% males was adequate to achieve optimum fertility.}, number={1}, journal={Poultry Science}, author={Davis, G.S. and Parkhurst, C.R. and Brake, J.}, year={1993}, pages={23–29} } @article{davis_edens_parkhurst_baughman_1991, title={COMPUTER-AIDED HEAT ACCLIMATION IN BROILER COCKERELS}, volume={70}, ISSN={["0032-5791"]}, DOI={10.3382/ps.0700302}, abstractNote={Abstract A battery-powered BASIC CMOS microcomputer was used to control the environment in a solar-assisted poultry house containing heat-acclimated and control broiler chickens. The computer features complete isolation from commercial power sources, power consumption in the 100-mA range, integrated circuit time clock, a 16-channel analog to digital converter to measure temperature, and 16 channels of output for control of poultry house equipment Three-week-old broiler cockerels were subjected to daily 4-h heating episodes (35 C) for 3 wk and then were exposed to heat stress (38 C) for 4 h. Based upon mortality and performance parameters, it was concluded that computer assisted-acclimation would be a method to improve heat resistance in broiler chickens.}, number={2}, journal={POULTRY SCIENCE}, author={DAVIS, GS and EDENS, FW and PARKHURST, CR and BAUGHMAN, GR}, year={1991}, month={Feb}, pages={302–306} } @article{davis_siopes_1985, title={THE EFFECT OF LIGHT DURATION ON TURKEY POULT PERFORMANCE AND ADRENAL-FUNCTION}, volume={64}, ISSN={["0032-5791"]}, DOI={10.3382/ps.0640995}, abstractNote={Day-old tom poults were exposed to one of the following light treatments: 1) continuous incandescent light (24LL), 2) 23L:1D incandescent light, 3) 12L:12D incandescent light, or 4) natural day lengths only. Mortality was recorded daily. At Weeks 1, 2, 4, 6, and 8, after poult placement, body weights and feed consumption were measured. At each of these times, 10 poults were sacrificed from each treatment group for evaluation of plasma corticosterone. Day lengths utilized in this study had no consistent effect on poult-performance parameters except from 0 to 2 weeks of age. During this time, poults in the 24LL and 23L:1D treatments consumed less feed but were similar in body weight to poults in the other treatments. Adrenal function was also not consistently affected by day length. However, in all treatment groups plasma corticosterone was lowest during the first 2 weeks posthatching, when compared to hormone levels at 4, 6, and 8 weeks. The lower corticosterone that occurred during the first 2 weeks posthatching may be involved in early poult mortality.}, number={5}, journal={POULTRY SCIENCE}, author={DAVIS, GS and SIOPES, TD}, year={1985}, pages={995–1001} }