Foram utilizadas 750 poedeiras comerciais de linhagens brancas com 23 semanas ao início do período experimental, distribuídas num delineamento em blocos completos aleatorizados sendo estes caracterizados pela oncatenação das linhagens com coluna de gaiolas; os tratamentos foram cinco densidades ou taxas de lotação na gaiola (321,43; 375; 450; 562,50 e 750 cm2/ave) com seis repetições, totalizando 150 parcelas experimentais. As dietas experimentais foram à base de milho e farelo de soja, formuladas para suprir as exigências nutricionais das linhagens em todas as fases. O desempenho produtivo e econômico foram avaliados através do peso dos ovos (g), percentagem de postura (%), massa de ovos (g/ave/dia), consumo de ração (g/ave/dia), conversão alimentar por dúzia (kg/dz) e por quilo de ovo (kg/kg). A qualidade de ovos foi avaliada através da gravidade específica (GE), unidades Haugh (UH), percentagens de gema, albúmen e casca, espessura da casca (EC), resistência à quebra (RQ), coloração da gema e índice gema (IG). O bem-estar das aves foi avaliado através de indicadores clínicos, imunológicos e fisiológicos. Para efeito da avaliação dos resultados, foram estabelecidos seis blocos com repetições internas. Os dados foram analisados com auxílio do SAS, sob modelo misto, considerando os efeitos da densidade, período e a interação entre estes, como fixos, além dos efeitos aleatórios de bloco e resíduo. Por se tratar de medidas repetidas longitudinalmente, buscou-se a melhor estrutura de covariância para cada variável. Quando adequado foi aplicado o teste de tukey-kramer para a comparação de médias (p<0,05). O menor consumo de ração, CA/dz de ovos e melhor desempenho econômico, foram obtidos pela densidade 321,4 cm2/ave. Altas densidades de alojamento não influenciaram a qualidade interna de ovos, a % casca e RQ, mas essas variáveis tiveram efeitos dos períodos, com os melhores valores nos primeiros períodos. Altas densidades tiveram efeitos negativos sobre a GE e EC, principalmente no pico de postura das aves. Os ovos avaliados encontravam-se dentro dos valores desejados, mesmo nas maiores densidades, podendo ser classificados como de excelente qualidade. A densidade de alojamento não interferiru (p>0,05) na avaliação clínica das aves, mas o maior espaço proporcionado nas gaiolas do sistema covencional conferiu menor freqüência de lesões nas aves, indicando promoção e melhora ao seu bem-estar geral. Dados de freqüência cardíaca e temperatura da cloaca estavam dentro dos padrões de normalidade para a espécie. Não foram observadas diferenças (p>0,05) das densidades na resposta imunológica das aves, com os títulos dos anticorpos vacinais contra as doenças de Gumboro e Newcastle acima dos níveis do ponto de corte (cutoff). Os tratamentos não modificaram o perfil sanguíneo das aves e não foi possível caracterizar um padrão de corticosterona no plasma e de excreção de metabólitos fecais de glicocorticoides. A técnica de enzimoimunoensaio, empregada utilizando anticorpo primário contra corticosterona e anticorpo secundário anticoelho de cabra, foi capaz de detectar as variações nas concentrações de corticosterona nesses tecidos, contudo, o entendimento do significado desses achados ainda necessita de novas investigações. / 750 commercial laying hens of white strains aged 23 weeks at the beginning of the experimental period were used, distributed in a randomized complete block design, these being characterized by the concatenation of the strains with column of cages; the treatments were five densities or stocking rates in the cage (321,43, 375, 450, 562.50 and 750 cm2/bird) with six replications, amounting to 150 experimental plots. The experimental diets were on the basis of corn and soybean meal, formulated to meet the nutritional requirements of the strains in all the phases. Both the productive and economic performances were evaluated through the weight of the eggs (g), percentage of laying (%), egg mass (g/bird/day), feed intake (g/bird/day), feed conversion per dozen (kg/dozen) and per kg of egg (kg/kg). Egg quality was determined through specific gravity (SG), Haugh units (HU), percentages of yolk, albumen and shell, shell thickness (ST), resistance to breaking (BR), yolk coloration and yolk index (YI). The welfare of the birds was evaluated through clinical, immunological and physiological indicators. For the purpose of evaluation of the results, six blocks with internal replications were established. The data were analyzed with the aid of SAS, under a mixed model, considering the effects of density, period and the interaction between them, as fixed, in addition to the random effects of block and residue. For se tratar de measures longitudinally repeated, the best covariance structure for each variable was sought. When appropriate, the Tukey-Kramer test was used for comparison of means (p<0.05). The lowest feed intake, FI/dozen of eggs and best economic performance, were obtained at the density of 321.4 cm2/bird. High housing densities did not influence the internal quality of the eggs, % shell and BR, but these variables had effects from the periods, with the best values in the early periods. High densities had negative effects on SG and ST, mainly at the laying peak of the birds. The eggs checked lie within the desired values, even at the highest densities and can be classified as of excellent quality. The housing density did not interfere (p>0.05) in the clinical evaluation of the birds, but the greater space provided in the cages of the conventional system conferred a lower frequency of lesions in the birds, indicating promotion and improvement to their general welfare. Data of heart rate and cloacal temperature were within the normal limits for the species. No differences (p>0.05) of the densities in the immune response of the birds, with the titers of the vaccine antibodies against Gumboro and Newcastle diseases above the cutoff levels were found. The treatments did not modify the blood profile of the birds and it was not possible to characterize a standard of plasma corticosterone and excretion of fecal metabolites of glucocorticoids, but the enzyme immunoassay technique, using primary antibody against corticosterone and secondary goat anti-rabbit antibody, was capable of detecting variations in the corticosterone concentrations in these tissues, however, the understanding of the meaning of these findings still requires further investigation.

I examined oviposition in four pond-breeding amphibians (northwestern salamander [Ambystoma gracile], long-toed salamander [Ambystoma macrodactylum], Pacific treefrog [Hyla regilla], northern red-legged frog [Rana aurora aurora]), at Burlington Bottoms, a lowland riverine site in northwestern Oregon, to determine whether differential use of native versus exotic plant substrates occurs. I found differential use in all four species, but use was inconsistent with the hypothesis that selection for native plants (or selection against exotic plants) was occurring. If selection was occurring, the pattern implied that reed canarygrass (Phalaris arundinacea), a widespread exotic in this lowland system, was sometimes favored. However, inconsistent use of reed canarygrass led me to examine the alternative that substrate strength (measured as density, diameter, and mass), rather than plant status, might be the basis of selection. Species used for oviposition differed in strength, but eggs were not consistently laid on braces based on my strength measures. Failure to find support for this hypothesis led to examination of a third hypothesis for two species (red-legged frog and northwestern salamander), that cover characteristics of the oviposition brace or nearby vegetation might influence egg mass location. Analysis of structural complexity of species used as a brace (as percent cover within 15 em of the egg mass) did reveal a pattern consistent with complexity, but that was species-specific. Red-legged frogs selected braces with significantly more nearspace cover; northwestern salamanders selected braces with sparser cover. Comparison of marginal shrub and tree cover to the number of red-legged frog egg masses revealed that ponds with < 50% shrub/tree cover had few (< 5) masses. Ponds with ≥ 50% shrub/tree cover had many (≥ 10) masses. More complex vegetation may provide greater protection for egg masses or ovipositing red-legged frogs but further investigation is clearly warranted. Elucidating northwestern salamander cover requirements will require examining more occupied ponds. In particular, more refined examination, using experimental manipulation, is needed to verify the cover relationships revealed in this study. Meanwhile, managers should treat cover as important in red-legged frog oviposition life history, paying special attention to minimizing loss of marginal shrub and tree cover.

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.

Poultry and egg purchases represent a substantial part of the consumers' dollar spent for food. The Marketing and Transportation Situation reported that the average American family of 3.3 persons used 11.3 percent of its food expenditures for the purchase of chickens and eggs in 1953. This means that the average family spent $113.00 for eggs and chickens during that year.

Includes bibliographical references

The mechanisms responsible for overland transport of faecal pathogens, particularly Cryptosporidium oocysts, from animal sources to water bodies are not fully understood. Surface properties of microbes, such as electrostatic charge and hydrophobicity, are thought to contribute to their aggregation and attachment to solid surfaces. There is conflicting evidence that methods used to purify Cryptosporidium oocysts from faecal material may affect the oocyst surface, leading to biased conclusions from transport studies. By studying oocyst surface properties, aggregation and soil attachment, this thesis addressed whether oocyst purification methods influence overland transport studies, and whether oocysts are likely to be associated with particles during transport. When using the microbial adhesion to hydrocarbon (MATH) assay with octane, oocyst hydrophobicity was shown to be method and isolate dependent, with oocysts displaying moderate to high hydrophobicity in 0.01 M KNO3. There was no observed attachment, however, to the hydrophobic octyl-SepharoseTM bead ligands when using the same suspension solution. Oocyst age did not appear to influence their hydrophobicity. A small but statistically significant proportion of oocysts displayed a net negative surface charge as observed by their attachment to an anion exchange ligand (DEAE). There was no difference in hydrophobicity or surface charge observed between purified oocysts and oocysts that had been extracted without the use of harsh chemicals and solutions with dehydrating properties. Purified oocysts did not aggregate at pH values between 3.3 and 9.0, nor in solutions lower than 0.59 M in ionic strength at a pH 2.7 which is approaching the reported isoelectric point of oocysts. This finding suggests that oocysts may not form aggregates under general environmental conditions. The association of purified oocysts with soil particles was observed in settling columns. Attachment to soil particles was not conclusive since the settling of the soil particles may have entrained single oocysts. Nonetheless, approximately 27% of oocysts were estimated to be unbound to soil or associated with small soil particles. Hence models for oocyst overland transport should consider a significant fraction as single entities or associated with soil particles less than about 3 μm in size.

Corrigenda inserted behind title page. Copies of author's previously published articles inserted. Bibliography: leaves 193-210. This study investigated whether estrogen could modulate the proteins associated with calcium transport (eg calcium binding protein, calbindin D28k) in the intestinal tissue during sexual maturation of laying hens. The first study investigated the temporal and spatial expression of estrogen receptors (ER) and calcium binding protein in jejunal tissue. Findings indicated the potential of estrogen to induce calbindin D28K in the intestinal tissue, from which it can be concluded that estrogen may increase calcium absorption and consequently calcium retention. It was shown that the amount of estrogen normally present in the reproductive system is sufficient for the normal capacity of egg and eggshell production. Egg production and shell quality were significantly reduced by phytoestrogen. It is recommended that the concentration of phytoestrogen in poultry diets be investigated in more detail as it may act as an anti-nutritive factor and affect metabolism and productivity.

The purpose of this report was to compare Lilluns egg production with other Swedish egg producers based on the flow of nutrients (nitrogen, phosphorus and potassium) in the egg production systems. The main focus in the report was the utilization rate of the forage and the excess of nutrients per kg egg. Additionally, the purpose was to identify the environmental impact from Lilluns egg production and compare the results with other egg producers. The inflow of nutrients associated with forage and poultry was compared with the nutrients that were exported from the production. All of the egg producers in this study had an excess of nutrients. The utilization rate of the forage for Lilluns egg was 47 %, the other egg producers in this study had an utilization rate between 45-50 %. The results showed that Lilluns egg had an excess of nitrogen of 0,04 kg/kg eggs. Lilluns egg also had an excess of phosphorus and potassium. The excess of phosphorus was 0,01 kg/kg eggs and 0,013 kg/kg eggs for potassium. The results showed that all the egg producers in this study had an excess of all the nutrients. The conclusion is that the egg production systems in this study have a similar utilization rate and the excess of nutrients per kg egg was also similar for all the egg producers.

No description available.

No description available.