M J Wineland

North Carolina State University, Raleigh, North Carolina, United States

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Publications (39)28.61 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Footpad dermatitis begins early in life, and there is evidence of individual susceptibility. An experiment was conducted to evaluate the carryover effects of breeder feed restriction programs and incubation temperatures (TEM) on progeny footpad development at hatch, and 7 and 22 d. Cobb 500 fast feathering breeders were subjected to 2 dietary feed restriction programs during rearing: skip-a-day (SAD) and every-day feeding (EDF). At 60 wk of age, eggs from each group were collected and incubated according to 2 TEM, standard (S) eggshell temperature (38.1°C) and early-low late-high (LH). This second profile had low (36.9°C) eggshell temperature for the first 3 d, and standard temperature until the last 3 d when eggs were subjected to elevated (38.9°C) eggshell temperature. At hatch, 15 chicks from each treatment combination were sampled to obtain footpads for histological analysis. Seventy-two chicks per treatment were placed in 48 cages (6/cage), and raised to 22 d. At 7 and 22 d, 1 and 2 chickens, respectively, were sampled for footpads. The BW and group feed intake were recorded to obtain BW gain and feed conversion ratio at 7 and 21 d. Histological analysis assessed thickness and total area of stratus corneum (SC), epidermis, and dermis, and total papillae height. Data were analyzed as randomized complete block design in a 2 × 2 factorial arrangement of treatments. There was a negative effect of LH TEM on performance at both ages. An interaction effect on SC area and papillae height was observed at hatch. Additionally, SAD treatment increased thickness and area of footpad dermis. At 7 d, the SC parameters of the SAD progeny were increased. Epidermis thickness was affected by treatment interaction. Furthermore, LH TEM decreased epidermis thickness and dermis area. At 22 d, interaction effects were observed in thickness and area of SC and epidermis. Incubation S TEM increased thickness and area of dermis. It was concluded that breeder feed restriction programs and incubation TEM profiles may have carryover effects on histomorphological traits of footpads.
    Poultry science. 06/2014;
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    ABSTRACT: Abstract 1. The effects of diet type, feeding programme and fast or slow feed allocation in fast-feathering Cobb-500 broiler breeder hens on eggshell properties and broiler progeny bone development was investigated in a 2 x 2 x 2 factorial experiment. 2. The birds were fed on either maize or wheat based diets during rearing and production and a fast or slow feed allocation programme from 14 to 29 weeks of age. At 22 weeks, 69 females from each pen were placed in a layer house where feeder space (FS) either remained similar or was increased. 3. Eggs produced at 33 weeks were incubated, eggshell conductance (G) was determined, and a sample of 14 chicks from each treatment combination was taken to obtain bone traits at hatching.4. Diet type did not influence G, yolk-free BW, residual yolk weight, or relative asymmetry (RA) of any bilateral traits of leg bones of hatchlings. However, breeder diet type was involved on two-way and three-way interaction effects on progeny leg bone traits. 5. Breeders fed restricted according to the slow feeding programme laid eggs with greater G compared to those managed with the fast feeding programme, but there was no effect of feeding programme on progeny bone traits at hatching. 6. Eggs from breeders given more FS at photostimulation had greater G than those from breeders provided with similar FS. Maternal FS change did not influence hatchling yolk-free BW; however, breeders given more FS produced progeny with heavier tibias and shanks and longer femurs compared with those provided similar FS, but only when breeders were fed on maize. Moreover, increased maternal FS at photostimulation was associated with an increased RA of femur length in the progeny. 7. It was concluded that breeder feeder space change at photostimulation influenced eggshell conductance and consistently affected bone development of broiler progeny.
    British Poultry Science 05/2014; · 1.15 Impact Factor
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    ABSTRACT: A two-part serial survey of 49 broiler breeder farms was conducted in four south-eastern states: Arkansas, Alabama, Georgia and North Carolina. Broiler breeder farms from three to five broiler company complexes in each state were visited on two separate occasions to document management practices and perform environmental sampling for Salmonella prevalence estimation. Salmonella was detected in 88% of the broiler breeder houses that were sampled and was identified on all 49 farms enrolled. Many management characteristics were consistent across the different states and companies. Multilevel analysis was used to evaluate management characteristics as risk factors for Salmonella prevalence and to estimate the proportion of variance residing at the different hierarchical sampling levels. Management characteristics associated with increased Salmonella prevalence included treatment of the flock for any disease, having dusty conditions in the house, having dry conditions under the slats and walking through the house more than one time per day to pick-up dead birds. After adjusting for state as a fixed effect, the percentages of variance in Salmonella prevalence occurring at the complex, farm, visit, house and individual sample levels were 5.2%, 6.8%, 11.8%, 2.8% and 73.4%, respectively. The intraclass correlations for samples collected from the same house; for samples from different houses during the same visit; for samples from different visits to the same farm; and for samples from different farms in the same complex were as follows: 0.27, 0.24, 0.12 and 0.05, respectively.
    Zoonoses and Public Health 02/2012; 59(5):365-74. · 2.09 Impact Factor
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    ABSTRACT: Two experiments were conducted to examine the effects of broiler breeder dietary grain source and cage density on maternal antibody (MatAb) transfer to progeny in 2 genetic strains (A and B). Broiler breeders were assigned to 16 litter floor pens and fed either corn- or wheat-based diets. Breeders were administered 4 live vaccines against Newcastle disease virus (NDV). At 23 wk of age, pullets and cocks, which reflected the full BW distribution from each treatment, were moved to a cage breeder house and placed at 1 or 2 hens/cage. Breeders were artificially inseminated at 44 wk (experiment 1) and 52 wk of age (experiment 2). Eggs were collected for 8 d, incubated, and placed in individual pedigree bags at d 19 of incubation. Blood samples from 5 chicks per treatment combination were collected at hatch in both experiments. Spleen and bursa were collected from the same chicks for histomorphometry analyses in experiment 2. In the second experiment, 12 chicks per treatment were placed in cages. Progeny were provided diets based on the same grain (corn or wheat) as their parents. Serum samples were collected at 5, 9, and 13 d of age and analyzed for anti-NDV MatAb. Data were analyzed as a 2 × 2 × 2 factorial design considering strain, dietary grain source, and cage density as main factors. Interaction effects were observed in breeders and progeny. Experiment 1 showed that strain A chicks had lower levels of MatAb when hens were housed at 2 hens/cage rather than 1 hen/cage. The MatAb levels of strain B chickens were not affected by cage density in either experiment. Experiment 2 demonstrated similar effects of cage density on MatAb levels and the area of bursa follicles for both strains. Progeny of breeders fed corn-based diets had smaller spleen white pulp only when hens were housed at 2 hens/cage compared with 1 hen/cage. The results of these experiments suggest that breeder strain and cage-density conditions affected MatAb transfer to progeny and embryo development of spleen and bursa.
    Poultry Science 12/2011; 90(12):2730-9. · 1.52 Impact Factor
  • Journal of Applied Poultry Research - J APPL POULTRY RES. 01/2009; 18(3):447-451.
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    Journal of Applied Poultry Research - J APPL POULTRY RES. 01/2009; 18(4):671-678.
  • Journal of Applied Poultry Research - J APPL POULTRY RES. 01/2009; 18(3):640-646.
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    ABSTRACT: 1. Four experiments were conducted to evaluate the effects of temperature (TEM) and oxygen (O(2)) concentrations during the last 4 d of incubation on bone development. Fertile eggs from two strains were obtained that either exhibited Low or High eggshell conductance (G). 2. Four experimental cabinets provided either four TEM (36, 37, 38 or 39 degrees C) or four O(2) concentrations (17, 19, 21 or 23% O(2)). Data were analysed as a 2 x 2 factorial design. In the fourth experiment, two temperatures (36 and 39 degrees C), two O(2) concentrations (17 and 23%) and the same Low and High G strains were evaluated in a 2 x 2 x 2 factorial design. 3. Body weights (BW) and residual yolks were obtained, both legs were dissected. Femur, tibia and shank weights, length and thickness were recorded. Relative asymmetry (RA) of each leg section was calculated. 4. The results indicated that elevated TEM during incubation increased RA between the two legs, mainly in the Low G strain. Chickens at the lowest O(2) concentrations had lighter and shorter tibias, lighter shanks, and increased RA of femur length compared to chickens in the 23% O(2). In the fourth experiment no interactions were observed between O(2) and TEM. High TEM depressed BW of Low G broilers, but no significant effect of treatments was observed on BW of High G broilers. Nevertheless, the high TEM or low O(2) independently caused reduced femur and tibia weights and length, shank length and thickness, and both low O(2) and high TEM together increased RA in shank weight. 5. These results suggest that late incubation conditions affect long bone development in broilers.
    British Poultry Science 12/2008; 49(6):666-76. · 1.15 Impact Factor
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    ABSTRACT: Temperature (TEM) and O(2) concentrations during the plateau stage of oxygen consumption are known to affect yolk utilization, tissue development, and thyroid metabolism in turkey embryos. Three experiments were conducted to evaluate these incubation effects on long bone development. Fertile eggs of Nicholas turkeys were used. In each trial, standard incubation conditions were used to 24 d, when the eggs containing viable embryos were randomly divided into 4 groups. Four experimental cabinets provided 4 TEM (36, 37, 38, or 39 degrees C) or 4 O(2) concentrations (17, 19, 21, or 23% O(2)). In the third experiment, 2 temperatures (36 and 39 degrees C) and 2 O(2) concentrations (17 and 23%) were evaluated in a 2 x 2 factorial design. Body and residual yolk weights were obtained. Both legs were dissected, and shanks, femur, and tibia weights, length, and thickness were recorded. Relative asymmetry of each leg section was calculated. Chondrocyte density was evaluated in slides stained with hematoxylin and eosin. Immunofluorescence was used to evaluate the presence of collagen type X and transforming growth factor beta. Hot TEM caused reduction of tibia weights and increase of shank weight when compared with cool TEM. The lengths of femur, tibia, and shanks were reduced by 39 degrees C. The relative asymmetry of leg weights were increased at 38 and 39 degrees C. Poult body and part weights were not affected by O(2) concentrations, but poults on 23% O(2) had bigger shanks and heavier tibias than the ones on 17% O(2). High TEM depressed the fluorescence of collagen type X and transforming growth factor beta. The O(2) concentrations did not consistently affect the immunofluorescence of these proteins. The chondrocyte density was affected by TEM and O(2) in resting and hypertrophic zones. In the third experiment, high TEM depressed BW, leg muscle weights, and shank length. Low O(2) reduced tibia and shanks as a proportion of the whole body. We concluded that incubation conditions affect long bone development in turkeys.
    Poultry Science 08/2008; 87(8):1484-92. · 1.52 Impact Factor
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    ABSTRACT: High levels of phosphorus and pathogens in runoff are 2 major concerns following manure applications to fields. Phosphorus losses from fields following manure applications have been linked to the solubility of phosphorus in manure; therefore, by decreasing manure phosphorus solubility, a decrease in phosphorus loss in runoff should be apparent. The objective of this research was to develop a process using quicklime that would result in reduced phosphorus solubility and bacteria counts in broiler litter. The 4 litter treatments evaluated were T1, new wood shavings without the addition of quicklime; T2, used, untreated broiler litter; T3, used litter with 10% quicklime (based on the weight of the litter); and T4, used litter with 15% quicklime (based on the weight of the litter). Body weight, cumulative feed consumption, and feed conversion (feed:BW) were determined on a weekly basis through 42 d of age. Mortality was recorded daily. Carcass weights and percentages of carcass yield without giblets were determined prechill. Litter pH, total phosphorus, nitrogen, soluble phosphorus, litter moisture (%), and total plate counts were measured for each litter treatment on d 7 and 42 after bird placement. No significant differences were found for BW, feed consumption, feed conversion, mortality, carcass weight, or carcass yield. No breast or footpad blisters were observed. On d 7, 15% quicklime had higher (P < 0.001) pH (11.2) when compared with the other treatments. Percentages of phosphorus and nitrogen were lower (P < 0.001) for new wood shavings in comparison with the used litter treatments. Soluble phosphorus (ppm) was lower (P < 0.001) for 15% quicklime (2.75) when compared with new wood shavings (42.2), untreated broiler litter (439.2), and 10% quicklime (35.0). Although not significant, 15% quicklime had lower total plate counts (cfu/g) in comparison with the other treatments on d 1 and 10 postmixing and at 7 d after bird placement. Litter conditions on d 42 after bird placement were similar. We concluded that the use of quicklime as a treatment for broiler litter would initially reduce nitrogen and soluble phosphorus and bacteria counts without negatively affecting bird productivity.
    Poultry Science 05/2008; 87(5):823-7. · 1.52 Impact Factor
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    ABSTRACT: The effect of genetic strain (Ross 308; Cobb 500) and parent flock age [young (29 wk), peak (Ross = 34 wk; Cobb = 36 wk), postpeak (40 wk), mature (45 wk), old (55 wk), and very old (59 wk)] on eggshell conductance and embryonic metabolism were examined. At each flock age, eggs from each strain were incubated for 21.5 d in individual metabolic chambers to measure embryonic O(2) intake and CO(2) output. From these data, the respiratory quotient (RQ) and metabolic heat production were calculated. Data were analyzed by the GLM procedure of SAS at P < or = 0.05. Neither strain nor flock age influenced conductance. Total embryonic O(2) consumption, CO(2) output, RQ, and metabolic heat production over the entire incubation period were not affected by strain. Daily differences existed between strains for embryonic O(2) intake (1, 7, 16, 17, 19, 20 d of incubation), CO(2) output (1 to 4, 16 to 20 d of incubation), and heat production (4, 7, 16 to 19 d of incubation). Embryos from young, mature, old, and very old flocks produced significantly more total embryonic heat over the entire 21 d (1,712, 1,677, 1,808, and 1,832, respectively) than embryos from peak (1,601) and postpeak (1,693) flocks. Average RQ for the entire incubation period was higher in embryos from mature flocks compared with all other flock ages. Daily differences among embryos from different flock ages were shown for O(2) consumption (all but d 8 of incubation), CO(2) production (all but d 7 and 9 of incubation), and heat output. The results showed that genetic strain and parent flock age influence daily embryonic metabolism, especially during the early and latter days of incubation. These daily differences coincide with the days of incubation having a higher incidence of embryonic mortality; these 2 factors may be related. Further investigation into the relationship between embryonic metabolic heat production and mortality during incubation may lead to the development of specific incubation conditions for different genetic strains and flock ages.
    Poultry Science 11/2007; 86(11):2420-32. · 1.52 Impact Factor
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    ABSTRACT: It was hypothesized that incubator temperature and oxygen concentration affect embryo muscle development. Turkey eggs were incubated until the 24th day of development. At the beginning of the 24th day, the eggs containing viable embryos were randomly divided into 4 groups immediately prior to the plateau stage in oxygen consumption. Four experimental cabinets accommodating approximately 100 eggs were used for the actual hatching process. Each cabinet operated at predetermined temperatures (TEM) and oxygen concentrations (O ) in a 2 TEM (36° and 39°C) x 2 O (17 and 23%) factorial arrangement. At 27 and 2 2 28 days of development, immediately following the plateau stage, 10 embryos or poults were sampled from each of the 4 cabinets. Blood was obtained following decapitation. From each carcass the pipping (musculus complexus), breast (pectoralis thoracicus) and thigh muscles (gastrocnemus) were collected. Muscles were placed into an appropriate volume of 7% perchloric acid preparatory to assaying for glycogen and lactate. Five birds were sampled for histological analyses of muscle fibers. Plasma Creatine Kinase (CK) and lactate dehydrogenase (LDH) activities were measured. TEM and O affected muscle growth differently. High TEM 2 and O affected pipping and thigh muscle weights but not that of the breast muscle. Only TEM affected breast 2 muscle weights. Muscle function was affected differently when embryos were exposed to TEM and O. The 2 CK and LDH activities were also affected at 27 days 39°C causing elevated CK and LDH activities compared to 36°C. At 28 days, only CK was affected as 39°C elevated CK activity in the 23% oxygen environment but not in the 17% environment. Thus, incubator conditions may affect muscle development and function in poult embryos
    International Journal of Poultry Science. 01/2007;
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    ABSTRACT: The relationship describing eggshell conductance constants (k) suggests that eggshell conductance (G) is directly related to the length of the incubation period, but inversely with the weight of the egg. Prior studies showed clearly that G is a factor in cardiac health. We tested the hypothesis in the current study that the length of the incubation period may be a factor along with G that affects cardiac physiology and embryo survival. Incubation temperatures were reduced stepwise by 0.2<SUP>o</SUP>C in three treatments (37.5, 37.3 and 37.1<SUP>o</SUP>C) to prolong embryo developmental periods. The length of the developmental period was increased concomitantly in preliminary trials by 6 and 12 h, respectively by the 37.3 and 37.1<SUP>o</SUP>C treatments compared to 37.5<SUP>o</SUP>C. Fertilized eggs were incubated using the three temperatures in each of three independent trials. The time of hatching was closely noted and embryo survival was compared among treatments. Embryo heart rates and cardiac physiology in each group were observed. Long developmental periods reduced heart rates in a stepwise fashion and improved embryo survival and cardiac physiology. Thus, cardiomyopathy may be influenced by the length of the developmental period of turkey embryos because longer periods facilitated energy metabolism for myocardial function. Longer developmental periods would be easier to manage than G and may contribute to better turkey embryo viability late in development
    International Journal of Poultry Science. 01/2007;
  • Poultry Science 01/2006; 84(12):1814-5. · 1.52 Impact Factor
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    ABSTRACT: We hypothesize that temperature and oxygen in conjunction with genetic lines of broilers regulate embryo thyroid function. Thyroid response of broiler embryos of the two lines was measured at different incubator temperature and oxygen concentrations at the plateau stage in oxygen consumption (days 17 to 20 of embryo development). Each of the lines showed different eggshell conductance (G) values. Eggs of the same weight from the lines of broilers were incubated identically until the 17<SUP>th</SUP> day of development. On the 17<SUP>th</SUP> day (plateau stage in oxygen consumption), eggs were randomly distributed by line into four incubators operating at 36, 37, 38 or 39<SUP>o</SUP>C in trial 1 or at 17, 19, 21 or 23% oxygen in trial 2. At external pipping (the end of the plateau stage in oxygen consumption) as well as at hatching ten embryos or chicks per treatment were sampled for blood plasma. Plasma was analyzed for thyroxine and triiodothyronine concentrations. In trial 3, temperature line of broiler and oxygen treatments were arranged factorially. Increasing temperatures suppressed hormone concentrations in embryos, and the suppression was greater with low G. Increasing oxygen increased hormone concentrations in low G embryos to a greater degree than high G. It can be concluded that incubation temperature suppresses plasma thyroid hormone concentrations in low G lines whereas oxygen increases it.
    International Journal of Poultry Science. 01/2006;
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    ABSTRACT: Eggshell conductance (G) and incubator humidity (RH) were hypothesized to affect poult embryo survival and hatchling growth. Nearly 4,000 fertilized eggs of the same weight were selected (within 2 standard deviations of the mean). Selected eggs were divided randomly between two incubators. One cabinet operated at 65% RH whereas the second operated at 50% RH, and both cabinets had the same temperature (37.2<SUP>o</SUP>C). At the completion of the 24<SUP>th</SUP> day of development, all eggs were weighed a second time to determine eggshell G. Three groups were formed at this time by calculating eggshell conductance and sorting into groups of eggs exhibiting high (Hi), average (Avg) or low (Low) G. The eggs were then placed in the same incubation cabinet for hatching. Measurements were made of embryo cardiac and intestinal physiology. Samples were collected at external pipping and hatching from each of the groups. Tissues were assayed for plasma glucose and lactate, cardiac and hepatic glycogen and lactate. The RH and G effects on survival were noted, and poult weights were recorded for the first 6 weeks of age. More embryos from eggs of Hi or Avg G survived than Low G eggs, but poults from Hi G eggs did not grow as well as those from Avg or Low G eggs. Low G poults showed depressed cardiac glycogen and elevated lactate and had less mature intestines. Thus, in the developmental process of turkey embryos, G and RH may determine organ maturity at hatching thereby influencing survival and growth.
    International Journal of Poultry Science. 01/2006;
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    ABSTRACT: Heat shock protein 70 (hsp70) family of proteins, which functions as molecular chaperones, has been associated with tolerance to stressors in avian species. Selenium (Se) is an essential trace mineral incorporated into the seleno-enzymes such as glutathione peroxidase (GSHpx). GSHpx reduces oxidized glutathione (GSSG) to reduced glutathione (GSH) in the GSH/GSSG antioxidant system and protects cells from oxidative damage. This study was conducted to examine if the relationship between dietary supplementation of selenium to turkey (Meleagris gallopavo) hens and the embryonic expression of hsp70 and GSHpx activity in heat stressed embryos. Livers of embryos developing in eggs from turkey hens fed diets with or without supplemental Se were analyzed for hsp70 concentration and GSHpx activity before and after recovery from a heating episode. Before heat stress, hsp70 concentrations were equivalent in each treatment, but GSHpx activity was maximized in the SE treatment group. After recovery from the heating episode, hsp70 concentrations were significantly higher (P<0.05) in the non-Se-supplemented groups, but in the Se-supplemented groups the hsp70 concentrations were not different from pre-stress concentrations. In the pre-stress Se-supplemented group, liver GSHpx activity was significantly higher than GSHpx activity in the non-Se-supplemented embryo livers, and in the livers from embryos recovering from heat stress, GSHpx activity in the non-Se-supplemented group was lower than the pre-stress activity and significantly lower than the GSHpx activity in liver from Se-supplemented embryos recovering from heat distress. Se supplementation to the dams resulted in a significant increase in their embryos and that condition would facilitate a decreased incidence of oxidative damage to cells. A more reduced redox status in embryos from Se-supplemented dams decreased the need for cellular protection attributed to stress induced hsp70 and presumably allows heat distressed embryos to resume normal growth and development than embryos from dams with inadequate selenium nutrition.
    Comparative Biochemistry and Physiology - Part A Molecular & Integrative Physiology 01/2006; 142(4):427-32. · 2.17 Impact Factor
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    ABSTRACT: Stabilizing phosphorus (P) in poultry waste to reduce P losses from manured soils is important to protect surface waters, while pathogens in manures are an emerging issue. This study was conducted to evaluate CaO and Ca(OH)2 for killing manure bacterial populations (pathogens) and stabilizing P in poultry wastes and to investigate the influence on soils following amendment with the treated wastes. Layer manure and broiler litter varying in moisture content were treated with CaO and Ca(OH)2 at rates of 2.5, 5, 10, and 15% by weight. All treated wastes were analyzed for microbial plate counts, pH, and water-soluble phosphorus (WSP), while a few selected layer manures were analyzed by phosphorus X-ray absorption near edge structure (XANES). A loamy sand and a silt loam were amended with broiler litter and layer manure treated with CaO at rates of 0, 2.5, 5, 10, and 15% and soil WSP and pH were measured at times 1, 8, and 29 d. Liming reduced bacterial populations, with greater rates of lime leading to greater reductions; for example 10% CaO applied to 20% solids broiler litter reduced the plate counts from 793,000 to 6500 mL-1. Liming also reduced the WSP in the manures by over 90% in all cases where at least 10% CaO was added. Liming the manures also reduced WSP in soils immediately following application and raised soil pH. The liming process used successfully reduced plate counts and concerns about P losses in runoff following land application of these limed products due to decreased WSP.
    Journal of Environmental Quality 01/2006; 35(3):849-57. · 2.35 Impact Factor
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    ABSTRACT: An experiment was conducted to determine the effect of dietary P levels and dietary phytase enzyme (E) inclusion on Large White turkey breeder hen reproductive performance from 31 to 62 wk of age. Hens were placed in a curtain-sided house with 48 pens (10 birds per pen; 8 pens per treatment) at 31 wk and were fed a breeder ration with treatments as follows: HP, dietary available P = 0.55%; HPE, HP + E; MP, dietary available P = 0.35%; MPE, MP + E; LP, dietary available P = 0.17%; and LPE, LP + E. Feed and water were available ad libitum for 28 wk of lay. Diets were fed in mash form, and all other nutrients were formulated to meet or exceed NRC requirements. All hens were photostimulated in January (31 wk) with 15.5 h of light daily. Production data were recorded on a pen basis. Individual bird BW and feed consumption, by pen, were determined at monthly intervals from 31 to 62 wk. Hens were observed for weekly reproductive performance for hen housed egg production, hen-day egg production, settable eggs, cumulative settable eggs, hens out of lay, and hen mortality and for biweekly performance for egg fertility, hatchability of all eggs, hatchability of fertile eggs, egg weight loss, conductance, conductance constant (k), and embryonic mortality. Egg weight, eggshell thickness, egg components, and albumen and yolk P were measured monthly. At 62 wk of age, hen tibia P, plasma P, total fecal P, and water-soluble fecal P were determined. Decreasing dietary P resulted in no decreases in reproductive performance for turkey breeder hens to 62 wk. Additionally, decreased dietary P resulted in decreased total fecal P and water-soluble fecal P. Feeding turkey breeder hens dietary phytase enzyme resulted in significantly fewer hens going out of lay; however, this was not reflected in hen housed egg production. It was concluded that phosphorus could be lowered in turkey breeder hen diets, compared with current surveyed industry levels, without impairing reproductive performance.
    Poultry Science 04/2005; 84(3):485-93. · 1.52 Impact Factor
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    ABSTRACT: Avian embryo thyroid responses to incubator temperature and oxygen concentrations during the plateau stage in oxygen consumption were measured. It was hypothesized that turkey embryo thyroid responds in a limited way at this critical time to environmental conditions to modulate basal metabolism. Turkey embryos were exposed to one of four incubator temperatures (36, 37, 38 or 39<SUP>o</SUP>C) beginning on the 25th day of incubation at the onset of the plateau, a time when plasma thyroxine (T<SUB>4</SUB>) and triiodothyronine (T<SUB>3</SUB>) concentrations normally increase. Blood was collected and thyroid hormone concentrations were measured at pipping (27th day) and hatching (28th day). Elevated temperatures depressed T<SUB>3</SUB> and T<SUB>4</SUB> concentrations and increased the T<SUB>3</SUB> to T<SUB>4</SUB> ratios. In a second experiment four oxygen concentrations (17, 19, 21 or 23% oxygen) were provided to the embryos using identical procedures. The 21% treatment significantly reduced T<SUB>3</SUB> and T<SUB>4</SUB> at pipping compared to all other treatments, but 23% oxygen increased plasma T<SUB>3</SUB> and the T<SUB>3</SUB> to T<SUB>4</SUB> ratio compared to all other treatments. The 17% oxygen treatment elevated T<SUB>3</SUB> compared to all other treatments. At hatching, 23% oxygen elevated T<SUB>3</SUB> and T<SUB>3</SUB> to T<SUB>4</SUB> ratios compared to all other treatments. When temperature and oxygen treatments were applied together in a factorial arrangement, temperature and oxygen affected T<SUB>3</SUB> and T<SUB>4</SUB> hormone concentrations independently but did not interact. Therefore, we conclude that temperature and oxygen are independent stimuli of the avian embryonic thyroid gland during the plateau stage, and that incubator temperature and oxygen concentrations can modulate development of turkey embryos by changing plasma T<SUB>3</SUB> and T<SUB>4</SUB> concentrations.
    International Journal of Poultry Science. 01/2005;