• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 246
  • 182
  • 34
  • 21
  • 20
  • 11
  • 6
  • 5
  • 4
  • 4
  • 3
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 668
  • 123
  • 105
  • 100
  • 91
  • 79
  • 73
  • 63
  • 61
  • 50
  • 42
  • 40
  • 39
  • 39
  • 39
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Studies on Chicken Hatchability and Its Relation with Egg Yolk Metabolites

Zhang, Yi 03 February 2017 (has links)
No description available.
102

Reproductive decisions in the lesser black-backed gull Larus fuscus and their effects on reproductive success

Royle, Nicholas John January 1998 (has links)
The effect of several fundamental reproductive 'decisions' upon reproductive success were examined over a three year period at a large, inland gullery in the Pennines. Variations in reproductive parameters in relation to timing of breeding and reproductive success were compared among years. Determinants of the degree of hatching asynchrony were identified. Eggs from two years were taken for yolk lipid analysis, using gas chromatography. Variation in micronutrient content of eggs within clutches and between years was assessed in relation to egg size and yolk size, in order to examine resource allocation decisions of individuals. Timing of breeding of individuals was experimentally manipulated through the exchange of whole clutches of eggs between early and late laying birds, whilst controlling for variation in clutch size and egg-size, in order to assess whether the seasonal decrease in reproductive success was best explained by a decrease in food supply or differences in quality among parents. I experimentally manipulated the within-brood mass hierarchy of gulls, whilst controlling for variation in both chick quality and parental quality, in order to assess the effect of hatching asynchrony per se on chick growth and survival, and whether parents optimized the degree of hatching asynchrony with respect to the prevailing food supply. Brood size was experimentally reduced in order to assess the costs and benefits of the production of supernumary young. This was acheived by comparison of chick growth, feather development and chick survival of unmanipulated three-chick broods with broods where either the a-chick or the c- chick had been removed. I present a general discussion of the results within the context of life-history theory and a model for the evolution of hatching asynchrony in the lesser black-backed gull.
103

Efeito da suplementação dietética com micro minerais orgânicos na produção e qualidade de ovos de galinhas poedeiras / Effects of diet supplementation with organic trace minerals on production and egg quality for laying hens

Sechinato, Alexandre da Silva 18 December 2003 (has links)
Um experimento foi realizado para avaliar o efeito da suplementação dietética de fontes orgânicas de micro minerais na produção e qualidade interna e externa de galinhas poedeiras. Foram utilizados 8 tratamentos: um tratamento com todos os minerais na forma inorgânica, um tratamento com todos os minerais na forma orgânica e mais 6 tratamentos com apenas um dos minerais na forma orgânica. Os minerais testados foram: zinco, manganês, iodo, selênio, cobre e ferro. As dietas experimentais foram à base de milho e farelo de soja, foram utilizadas 672 aves da linhagem babcock B 300, o período de experimentação foi de 48 a 60 semanas de idade. Foram avaliados os seguintes parâmetros de produção: Consumo de ração, Produção de ovos, Peso de Ovos, Massa de ovos, Conversão Alimentar. Também foram avaliados parâmetros que qualidade do ovo: Gravidade específica, unidade Haugh, porcentagem de casca. Os dados foram analisado em ciclo de postura de 28 dias. Os resultados para a primeira análise de qualidade dos ovos demonstraram uma piora na unidade haugh para o tratamento contendo ferro orgânico (p<0,05) e uma piora na porcentagem de casca para os tratamentos com o zinco e com o cobre orgânico (p<0,05), quando comparado com o tratamento totalmente inorgânico. Para as demais análises não foram observadas diferenças estatísticas. Os resultados para a produção de ovos não foram diferentes para os três períodos, com exceção da massa de ovos que foi menor para o tratamento com o ferro orgânico para o terceiro ciclo de postura (p<0,05). Os resultados do experimento sugerem que a suplementação com minerais orgânicos não alteram a qualidade e a produção de ovos de galinha entre 48 e 60 semanas de idade, quando comparado com a suplementação inorgânica dos mesmos. / A experiment was conducted to study the effect of organic trace mineral sources supplementation on egg production and quality for laying hens. It were used 8 treatments: one treatment with every trace minerals on inorganic form, one treatment with all minerals on organic form and 6 treatments where only one mineral were organic. The trace minerals were: zinc, manganese, iodine, selenium, copper and iron. Corn and soybean meal diets were used. 672 babcock B300 laying hens with 48 week were used. The production parameters analyzed were: Feed intake, egg production, egg weight, egg mass and feed conversion. The parameters of egg quality analyzed were: specific gravity, haugh unit and eggshell percent. Data were summarized for 3 periods of 28 days and analyzed by SAS. The results for first analyzes of egg quality showed a decrease in Haugh unit for the treatment with organic iron (p<0,05) and a decrease on eggshell percent for the chelates zinc and copper (p<0,05), when this results were compared with the inorganic mineral supplementation. For the other parameters weren’t showed statistic differences. The results for egg production weren’t different for the tree periods, except for egg mass that was decrease to organic iron treatment in the last period (p<0,05). The experiment results suggest that the supplementation with organic minerals didn’t improve the egg production and quality for laying between 48 – 60 weeks of age, when its were compared with inorganic mineral supplementation.
104

Qualifying kinship : how do UK gamete donors negotiate identity-release donation?

Gilman, Leah Isabelle January 2017 (has links)
With effect from 1st April 2005, UK law was amended such that gamete donors must now consent to their identity being released to their donor offspring, should they request it after the age of eighteen. This qualitative study investigates the views and experiences of those donating in this new context. Drawing primarily on twenty-four in-depth interviews with donors, supplemented by twenty staff interviews and observation in two fertility clinics, I examine how donors make sense of their role in relation to offspring, recipients and the wider community. I argue that donors make sense of their role as “biological” parents to offspring through creative reference to kinship repertoires, drawing on their own experiences of “doing family.” However, crucially, kinship connections are always qualified in some way to show that they are not quite family to donor offspring, and certainly not their “real” parent. Often this discursive work involved emphasising their relationship to recipients or the wider community (rather than offspring), framing the donation as a gift or a public act. In addition, donors drew on their kinship expertise to dilute, reshape or “re-route” their connection to offspring. Ultimately, this is a thesis about the limiting work involved in “doing kinship.” I demonstrate that donors did this limiting work in highly creative ways, not restricted to forgetting or ignoring connections. Instead, I show that not constructing kinship claims can be as active a process as making them.
105

Descrição do comportamento da cepa de Salmonella Enteritidis PT4 frente ao tratamento térmico a 60,0°C por três minutos e meio, em ovo integral pasteurizado desidratado reconstituído / Description the behavior of Salmonella Enteritidis PT4 undergoing thermal treatment at 60°C for 3 ½ minutes, in reconstituted dried-wole egg

Toledo, Paula Spinha de 03 December 2003 (has links)
O presente trabalho objetivou descrever o comportamento da cepa Salmonella Enteritidis (S. Enteritidis) PT4, frente ao tratamento térmico a 60,0º C por três minutos e meio, em ovo integral pasteurizado desidratado reconstituído, interrelacionando a termorresistência com temperatura prévia de incubação e concentração de microrganismos. Foram realizadas 150 análises, das quais 75 foram trabalhadas com cepa previamente incubada à 35ºC e 75 com cepa incubada à 43ºC. Cada um destes grupos foi subdividido em três subgrupos, inoculado-se as concentrações de 10³, 105 e 108 unidades formadoras de colônia (UFC)/mL de caldo BHI. Após inoculação, foi simulada pasteurização do ovo, a 60,0ºC por 3,5 minutos, em banho-maria, e, posteriormente, realizadas contagem em placa (UFC) e Número Mais Provável (NMP), para verificação da concentração de S. Enteritidis sobrevivente. O tempo de redução decimal (valor D) foi de 2,54 e 2,57 minutos para S. Enteritidis previamente incubada à 35ºC e inoculada nas concentrações de 105 e 108 UFC/mL de caldo BHI, respectivamente. Para S. Enteritidis previamente incubada à 43ºC e inoculada nas concentrações de 105 e 108 UFC/mL de caldo BHI, o valor D foi de 2,58 e 2,40 minutos, respectivamente. Não foi possível o cálculo do valor D para a concentração 10³ UFC/mL de caldo BHI, visto que não houve população sobrevivente. Não houve diferença significativa entre os resultados de contagem e NMP, comparando-se as duas temperaturas de incubação, entretanto, os resultados de contagem e NMP das três concentrações inoculadas foram diferentes entre si. Concluiu-se que a cepa pré incubada a 43ºC não apresentou maior resistência ao calor, em relação à cepa incubada a 35ºC; e não houve maior resistência ao calor, comparando-se as diferentes concentrações. / The purpose of this study was to describe the behavior of Salmonella Enteritidis (S. Enteritidis) PT4 undergoing thermal treatment at 60ºC for 3 ½ minutes in reconstituted dried-whole egg, correlating the heat resistance with a previous temperature of incubation and microrganism concentration. 150 analyses were conducted, 75 with S. Enteritidis PT4 previously incubated at 35ºC and 75 with S. Enteritidis PT4 previously incubated at 43ºC. Each of these two groups was subdivided in 3 sub-groups, adding the inoculum at concentrations of 10³, 105, 108 CFU/mL of BHI broth. After the inoculation, pasteurization of the egg was simulated at 60ºC for 3,5 minutes in a water bath. Then colony count and Most Probable Number (MPN) were carried out to check the concentration of surviving S. Enteritidis. The decimal reduction time (D-value) was 2.54 and 2.57 minutes for S. Enteritidis previously incubated at 35ºC and inoculated in the concentration of 105 and 108 CFU/mL of BHI broth, respectively. Concerning the S. Enteritidis previously incubated at 43ºC and inoculated in concentrations of 105 and 108 CFU/mL of BHI broth, the D-value was 2.58 and 2.40 minutes, respectively. It was not possible to calculate the D-Value for the 10³ CFU/mL concentration of BHI broth, because there was no surviving population. There was no significant difference between the results of colony count and MPN, comparing the two incubation temperatures, however the results of colony count and MPN of the three inoculated concentrations were different from each other. It was possible to conclude that the S. Enteritidis PT4 previously incubated at 43ºC hadn´t shown more heat resistance if compared with the S. Enteritidis PT4 incubated at 35ºC; and there wasn’t more heat resistance, comparing the different concentrations.
106

A critical appraissal of the home-based food security projects with reference to layers at Makhuduthamaga Sekhukhune District in Limpopo Province

Monyela, Mante Thabitha Daisy January 2007 (has links)
Thesis (M.Sc) (Agriculture) --University of Limpopo, 2007. / It is beyond doubt that a large proportion of the population in the rural areas are experiencing great difficulty in securing adequate food in both amount and quality. Poverty alleviation programs are embarked in various countries with Makhuduthamaga being no exception. The study was designed to evaluate the home-based egg production projects. The study was conducted at Makhuduthamaga sub- District of Sekhukhune District of Limpopo province. Two instruments were used for data collection namely Delphi technique and two structured questionnaires. The Delphi technique was used for both the beneficiaries and the extension officers to identify, list and rank in order of importance the constraints which impacted negatively on egg production as well as the actions taken to address those constraints. Two separate questionnaires were also used to collect data from both the beneficiaries and the extension officers. Out of twenty villages a list of 231 beneficiaries of starter up packs was identified. Krecjcie and Morgan (1970) sample estimation required 144 randomly selected beneficiaries of starter up packs to participate in the study which reflected 0.6 margin of error. The two questionnaires with open ended and closed ended questions were piloted at Fetakgomo District in four villages with thirty one beneficiaries and ten extension officers. Reliability was found to be 0.81 skills, 0.80 for support from extension officers and 0.61 for government expectations. The Statistical Package for the Social Sciences was used for the entering data collected. Descriptive statistics were used to analyse data. The findings revealed that the majority of the beneficiaries fall within the prescribed selection criteria. Almost all except one village were given the starter up packs namely 18 layers, four bags of laying mash, cage, nipples, feeding trays and a cage as outlined in the policy. Training was considered by both the beneficiaries and the extension officers as inadequate for effective and efficient running of the home based egg production projects. The results revealed that the majority of beneficiaries did not meet government expectations. An acknowledgement was made that during the implementation of projects mistakes were committed by both beneficiaries and extension officers. Analysis of variance was also used to determine the relationship between the level of education and the extent to which government expectations were met. There was no significant relationship between skills such as technical, management, financial, administration and the extent to which government expectations were met. However there was a significant relation between marketing skills and levels of education. The majority of beneficiaries had a low level of education. Pearson correlation coefficient was used to determine whether there is a relationship between skills and support from the extension officers and the extent to which government expectation were met. Skills such as technical and marketing as well as the support from the extension officers attributed much to variations with regard to the extent to which government expectation were met. Constraints were also encountered which impacted negatively on egg production. Extension officers identified the following constraints such as survey not done prior to distribution, insufficient human resources, training, insufficient monitoring, inadequate transport, inability of beneficiaries to purchase feed, inadequate starter packs and failure to establish cooperatives. Beneficiaries identified constraints such as feed, training, diseases and unavailability of veterinarian, mortality of layers on arrival, theft and predation, inadequate starter packs, layers not of the same age and cages that are too small. Out the constraints mentioned only three namely insufficient transport, inadequate starter up packs `and one aspect on feed i.e. soft shelled eggs were addressed. Although the majority of beneficiaries considered home based egg production projects inadequate in providing access to adequate food, slightly over half of them favoured them as future household projects. / Kellog Foundation
107

The effect of egg weight hatchability, chick hatch-weight and subsequent productivity of Venda chickens

Thamaga, Marupine Windy January 2010 (has links)
Thesis (M.Sc. (Agric)) --University of Limpopo, 2010 / An experiment was conducted to determine the effect of egg weight on hatchability, hatch-weight and subsequent productivity of Venda chickens. A total of 360 Venda chicken eggs based on their weights were collected within one week and assigned to four treatments with five replicates of 18 eggs per replicate. A randomized design was used. The four treatment weights were below 49 g, between 50 and 59 g, between 60 and 69 g and above 70 g. the eggs were incubated for 21 days. The chicks were raised up to 13 weeks based on their treatments but fed a similar diet. Egg weight was positively and strongly correlated (r2 = 0.727) with hatchability. Similarly, egg weight was positively and strongly correlated (r2 = 0.0.953) with chick hatch-weight. Between one and seven weeks old, Venda chicks hatched from heavier eggs ate less (P< 0.05) than those hatched from lighter eggs. Heavier eggs hatched chicks with better (P< 0.05) feed conversion ratio. However, chicks hatched from heavier eggs tended to have higher (P< 0.05) live weight at seven weeks old than those hatched from lighter eggs. Heavier eggs tended to hatch chicks that had higher (P< 0.05) mortality rates. However, metabolisable energy and nitrogen retention of the chicks aged seven weeks was not (P> 0.05) affected by egg weight. Growth rate and live weight of the chicks aged between one and seven weeks were optimized at different Venda chicken egg weights of 56 (r2 = 0.514) and 60 (r2 = 0.870) g, respectively. Egg weight had no (P> 0.05) effect on metabolisable energy, feed conversion ratio, growth rate, live weight, carcass weight and carcass parts of Venda chickens aged between eight and 13 weeks except fat pad weight. Venda chickens hatched from lighter eggs had lower (P< 0.05) fat pad weights than those hatched from heavier eggs. Meat samples of chickens hatched from lighter eggs had higher (P< 0.05) nitrogen contents. It is concluded that Venda chicken egg weight affects (P< 0.05) egg hatchability, chick hatch-weight, growth rate, live weight and carcass characteristics of the chicken. However, these variables are optimized at different egg weights. This has implications on selecting eggs for incubation.
108

Effect of egg weight on hatchability, chick hatch weight and subsequent productivity of Venda chickens

Thamaga, Marupine Windy January 2011 (has links)
Thesis (M.Sc. Agric.(Animal Science)) --University of Limpopo, 2011 / An experiment was conducted to determine the effect of egg weight on hatchability, hatch-weight and subsequent productivity of Venda chickens. A total of 360 Venda chicken eggs based on their weights were collected within one week and assigned to four treatments with five replicates of 18 eggs per replicate. A randomized design was used. The four treatment weights were below 49 g, between 50 and 59 g, between 60 and 69 g and above 70 g. the eggs were incubated for 21 days. The chicks were raised up to 13 weeks based on their treatments but fed a similar diet. Egg weight was positively and strongly correlated (r2 = 0.727) with hatchability. Similarly, egg weight was positively and strongly correlated (r2 = 0.0.953) with chick hatch-weight. Between one and seven weeks old, Venda chicks hatched from heavier eggs ate less (P< 0.05) than those hatched from lighter eggs. Heavier eggs hatched chicks with better (P< 0.05) feed conversion ratio. However, chicks hatched from heavier eggs tended to have higher (P< 0.05) live weight at seven weeks old than those hatched from lighter eggs. Heavier eggs tended to hatch chicks that had higher (P< 0.05) mortality rates. However, metabolisable energy and nitrogen retention of the chicks aged seven weeks was not (P> 0.05) affected by egg weight. Growth rate and live weight of the chicks aged between one and seven weeks were optimized at different Venda chicken egg weights of 56 (r2 = 0.514) and 60 (r2 = 0.870) g, respectively. Egg weight had no (P> 0.05) effect on metabolisable energy, feed conversion ratio, growth rate, live weight, carcass weight and carcass parts of Venda chickens aged between eight and 13 weeks except fat pad weight. Venda chickens hatched from lighter eggs had lower (P< 0.05) fat pad weights than those hatched from heavier eggs. Meat samples of chickens hatched from lighter eggs had higher (P< 0.05) nitrogen contents. It is concluded that Venda chicken egg weight affects (P< 0.05) egg hatchability, chick hatch-weight, growth rate, live weight and carcass characteristics of the chicken. However, these variables are optimized at different egg weights. This has implications on selecting eggs for incubation.
109

The Cost of Producing Eggs in Utah, 1946

Allred, Chall 01 May 1947 (has links)
The production of poultry and poultry products is one of Utah's major agricultural industries. In 1945, 22 percent of the farm income in Utah was derived from poultry and poultry products. About 10 percent of the total farm income was from eggs.
110

Análise histomorfológica e imuno-histoquímica de fragmento de gengiva inserido em membrana corioalantóica de ovos fecundados de galinha / Histomorphological and imunohistochemistry analysis of gingival fragments inserted in chorioallantoic membrane of chicken eggs

Huang, Isaac 25 September 2018 (has links)
A membrana corioalantóica (MCA) é uma das membranas extraembrionárias do embrião da galinha, cuja característica principal é ser muito vascularizada e permeável a trocas iônicas e gasosas. O ambiente onde está inserida permite o desenvolvimento de vários modelos experimentais, incluindo estudos de angiogênese, toxicologia e biocompatibilidade, bem como análise do processo de reparo e de carcinogênese de inúmeros tecidos. O objetivo deste trabalho foi verificar as alterações histomorfológicas de fragmentos de gengiva enxertados na MCA, com o intuito de verificar a viabilidade da utilização desse modelo em estudos envolvendo a mucosa oral. Fragmentos de gengiva foram coletados de pacientes submetidos a cirurgia de exodontia e enxertados na MCA de ovos fecundados de galinha após 9 dias de desenvolvimento embrionário. A coleta das gengivas foi feita após 1, 3 e 5 dias de inserção na MCA. As alterações morfológicas microscópicas foram anallisadas no decorrer do tempo no epitélio e na lâmina própria da gengiva e na MCA. Análise de TUNEL foi realizada para se comprovar a presença ou não de apoptose nos tecidos da gengivais. Foram realizadas também análises imuno-histoquímicas e quantificação da expressão de queratinas 10 (K10) e 14 (K14), para verificar as alterações de diferenciação epitelial, e CD34, para mensuração da vascularização. Do total de 25 ovos embrionados utilizados, 10 ovos receberam as gengivas para o experimento; o restante não mostrou viabilidade embrionária e foi descartado. Após 1 dia de inoculação, a interface MCA-gengiva exibiu intenso infiltrado inflamatório, o qual invadiu a lâmina própria. Após 5 dias, essa reação inflamatória ficou restrita à interface MCA-gengiva. As principais modificações morfológicas na gengiva foram observadas nos períodos de 3 e 5 dias de inoculação, em que houve perda da arquitetura do epitélio, mantendo-se somente a camada basal viável, e redução da celularidade na lâmina própria. Observou-se aumento da vascularização no período de 5 dias, atestada pela quantificação de vasos CD34 positivos. O epitélio remanescente exibiu ausência de estratificação e de expressão de K10, intensa marcação de K14 e células TUNEL negativas, sugerindo a presença de células epiteliais viáveis e pouco diferenciadas. Concluiu-se que a gengiva foi incorporada à MCA, com redução paulatina da reação inflamatória e revascularização, bem como manteve-se viável nesse ambiente em um período de 5 dias; contudo, sofreu processos de adaptação que incluíram a perda da estratificação epitelial e a redução da celularidade na lâmina própria. / Chorioallantoic membrane (CAM) is one of the chicken embryo extra embryonic membrane, whose main characteristic is being very vascularized and permeable for ionic and gaseous exchanges. The environment where it is inserted allows the development of many experimental model, including studies about angiogenesis, toxicology and biocompatibility, as well as analysis of the repair process and carcinogenesis of many tissues. The objective of this study was to verify the histomorphological changes of gingival fragments grafted on CAM, with the intent to check the viability of this model in studies involving oral mucosa. Fragments of gingiva were collected from patients undergoing dental extraction and grafted on CAM of fertilized chicken egg after 9 days of embryonic development. The collect of gingiva were made after 1, 3 and 5 days of insertion on CAM. The morphological alterations were analyzed over the time in the epithelium and lamina propria of gingiva and CAM. TUNEL analysis were made to evaluate the presence or not of apoptosis in the gingival tissue. Imunohistochemistry and quantification of the expression of keratin 10 (K10) and 14 (K14) were also made to check any alteration of epithelial differentiation, and CD34, for measurement of vascularization. Total of 25 fertilized egg were used, 10 eggs received gingiva for experiments; remaining egg didn\'t show embrionary viability and were discarded. After 1 day of inoculation, the CAM-gingiva interface exhibited a intense inflammatory infiltrate, which invaded the lamina propria. After 5 days, this inflammatory reaction were restricted to the CAM-gingiva interface. The main morphological changes in the gingiva were observed between 3 to 5 days of inoculation, in which there was loss of epithelial architecture, only the basal layer were viable, and a reduction of cellularity in lamina propria. Were observed a increase of vascularization in period of 5 days, attested by the quantification of positive CD34 vessel. The remaining epithelia showed the absence of stratification and expression of K10, intense marking of K14 and TUNEL cell negative, suggesting the presence of viable epithelial cells and less differentiated. It was concluded that the gingiva was incorporated by CAM, with gradual reduction of inflammatory reaction and revascularization, as well remained viable in this environment in a period of 5 days; however, it underwent processes of adaptation that included the loss of epithelial stratification and the reduction of cellularity in the lamina propria.

Page generated in 0.0264 seconds