Made available in DSpace on 2014-06-11T19:28:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-08-15Bitstream added on 2014-06-13T20:37:15Z : No. of bitstreams: 1 scherer_mr_me_botfmvz.pdf: 181041 bytes, checksum: 323fdced019a1fe2524b9da8665d9db0 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O objetivo deste estudo foi avaliar métodos alternativos de muda forçada e compará-los ao método convencional (jejum) e ao grupo controle. Para isso realizou-se o experimento nas instalações do Setor de Avicultura da Faculdade de Medicina Veterinária e Zootecnia UNESP Botucatu SP. Foram utilizadas 480 aves da linhagem Isa Brown, com 80 semanas de idade, distribuídas em 6 tratamentos contendo 10 repetições de 8 aves por gaiola. O período experimental compreendeu período de descanso forçado com duração de 28 dias onde se avaliou os parâmetros de peso corporal, ovário, oviduto, fígado, gordura abdominal, teores de cálcio e fósforo contido na cinza do metatarso e desempenho produtivo das aves. Os tratamentos utilizados foram dietas de produção com restrição de componentes: T1 cálcio e fósforo, T2 cálcio, fósforo e sódio, T3 cálcio, fósforo, sódio e aminoácidos (metionina e lisina), T4 fornecimento de milho moído, T5 muda convencional através de jejum de 14 dias seguido de ração de produção até 28 dias e T6 grupo controle que recebeu ração de produção. Durante a muda todos os tratamentos receberam água e retirou-se o programa de luz artificial. O T5 promoveu maior perda de peso corporal que os demais tratamentos. Tais perdas repercutiram em incremento no consumo voluntário de ração de produção nas primeiras semanas após o período de jejum. O jejum permitiu uma completa regressão do trato reprodutivo das aves, que cessaram a postura no período. Os tratamentos com restrição de nutrientes e de milho, promoveram redução do peso vivo, do aparelho reprodutivo e do consumo voluntário de ração, porém não cessaram a produção de ovos. / The objective of this study was to evaluate alternative forced molting systems and compare then to the traditional system (fasting) and to the control group. The trial was carried out at the Faculdade de Veterinária e Zootecnia (UNESP-Botucatu) Poultry Section. Four hundred and lighty 488 Isa Brown line hens, 80 weeks old, were assigned to 6 treatments with 10 replicates of 8 hens per cage. The experiment comprised, a 28 day resting period during which, we evaluated live weight, ovary, oviduct, liver, abdominal fat, calcium and phosphorus in tarsus ash and production traits. Treatments were production diets with nutrient or ingredient restriction: T1 calcium and phosphorus, T2 calcium, phosphorus and sodium, T3 - calcium, phosphorus, sodium and aminoacids (lysine and methionine), T4 ground corn feeding, T5 conventional forced molting: 14 days fasting followed by production ration feeding until 28 days, T6 control group fed production ration. During the molting period all hens had access to water and the light program was suspended. TheT5 promoted larger bady weight loss than the other treatments. Such losses resulted in an increment in the voluntary intake in the first weeks after the fasting period. Fasting allowed a complete regression of the reproductive tract of the birds and interrupted laying. The ingredient restriction treatments and ground corn feeding promoted reduction of body weight, of the reproductive tract and of the voluntary feed intake. They reduced, bit they didn't interrupt the egg laying.

Orientador: Edivaldo Antonio Garcia / Banca: Silvana Martinez Baraldi Artoni / Banca: Ricardo de Albuquerque / Resumo: O objetivo deste estudo foi avaliar métodos alternativos de muda forçada e compará-los ao método convencional (jejum) e ao grupo controle. Para isso realizou-se o experimento nas instalações do Setor de Avicultura da Faculdade de Medicina Veterinária e Zootecnia UNESP Botucatu SP. Foram utilizadas 480 aves da linhagem Isa Brown, com 80 semanas de idade, distribuídas em 6 tratamentos contendo 10 repetições de 8 aves por gaiola. O período experimental compreendeu período de descanso forçado com duração de 28 dias onde se avaliou os parâmetros de peso corporal, ovário, oviduto, fígado, gordura abdominal, teores de cálcio e fósforo contido na cinza do metatarso e desempenho produtivo das aves. Os tratamentos utilizados foram dietas de produção com restrição de componentes: T1 cálcio e fósforo, T2 cálcio, fósforo e sódio, T3 cálcio, fósforo, sódio e aminoácidos (metionina e lisina), T4 fornecimento de milho moído, T5 muda convencional através de jejum de 14 dias seguido de ração de produção até 28 dias e T6 grupo controle que recebeu ração de produção. Durante a muda todos os tratamentos receberam água e retirou-se o programa de luz artificial. O T5 promoveu maior perda de peso corporal que os demais tratamentos. Tais perdas repercutiram em incremento no consumo voluntário de ração de produção nas primeiras semanas após o período de jejum. O jejum permitiu uma completa regressão do trato reprodutivo das aves, que cessaram a postura no período. Os tratamentos com restrição de nutrientes e de milho, promoveram redução do peso vivo, do aparelho reprodutivo e do consumo voluntário de ração, porém não cessaram a produção de ovos. / Abstract: The objective of this study was to evaluate alternative forced molting systems and compare then to the traditional system (fasting) and to the control group. The trial was carried out at the Faculdade de Veterinária e Zootecnia (UNESP-Botucatu) Poultry Section. Four hundred and lighty 488 Isa Brown line hens, 80 weeks old, were assigned to 6 treatments with 10 replicates of 8 hens per cage. The experiment comprised, a 28 day resting period during which, we evaluated live weight, ovary, oviduct, liver, abdominal fat, calcium and phosphorus in tarsus ash and production traits. Treatments were production diets with nutrient or ingredient restriction: T1 calcium and phosphorus, T2 calcium, phosphorus and sodium, T3 - calcium, phosphorus, sodium and aminoacids (lysine and methionine), T4 ground corn feeding, T5 conventional forced molting: 14 days fasting followed by production ration feeding until 28 days, T6 control group fed production ration. During the molting period all hens had access to water and the light program was suspended. TheT5 promoted larger bady weight loss than the other treatments. Such losses resulted in an increment in the voluntary intake in the first weeks after the fasting period. Fasting allowed a complete regression of the reproductive tract of the birds and interrupted laying. The ingredient restriction treatments and ground corn feeding promoted reduction of body weight, of the reproductive tract and of the voluntary feed intake. They reduced, bit they didn't interrupt the egg laying. / Doutor

In the first part of the study an experimental design was followed whereby 600 DeKalb Amber-link® commercial laying pullets were subjected to three levels of EM bokashi (0.5%, 1.0% and 1.5%) and a standard level of a coccidiostat in the starter (17% CP, 0.9% Ca and 0.4% available phosphate) and grower (15% CP, 0.8% Ca and 0.35% available phosphate) diets from day-old to 16 weeks of age. EM treatments did not significantly affect the average weekly body mass, average daily gain, average weekly feed intake, cumulative weekly feed intake, cumulative feed conversion ratio and the average bi-weekly shank length over the control. The coccidiostat treatment maintained significant lower body weights, average daily gains and worse feed conversion ratios than all the EM treatments and the control throughout the trial period of 16 weeks. Although not significant the EM 1.5% level had the best feed conversion ratio, the highest body mass and the longest shank length at the end of the trial period at week 16. Mortalities were not treatment linked. / Dissertation (MSc Agric (Nutritional Science))--University of Pretoria, 2006. / Animal and Wildlife Sciences / unrestricted

Poultry have many behavioural, structural and biological features that are ideal for domestication and for meat and egg production (Appleby et al., 1992). Because of the importance of poultry meat and eggs to the human population, breeders and farmers are always looking for ways of improving these traits. Artificial selection is the primary method of trait improvement, and involves selecting individuals with the highest breeding values as parents in each generation. There are a number of different methods of artificial selection, including: individual selection, between family selection, within family selection, family-index selection and index selection. In order to maintain a good response to selection breeders are constantly striving to improve the effectiveness and accuracy of the different methods of artificial selection for traits of economic importance. One method of achieving this goal is the use of computer models. Computer models can be used to simulate selection strategies and to predict what strategy will be the most appropriate for the improvement of a particular trait. This is important as all traits are influenced by many different genetic and environmental factors (Falconer and Mackay, 1996). This investigation was designed to compare the effectiveness of five different artificial selection strategies, namely individual selection, between family selection, within family selection, family index selection and index selection. Five computer models were developed using Microsoft Excel 2000 and these models were then used to compare the efficiencies of the five selection strategies for four different traits. The selection techniques were applied to an artificially, randomly generated population of 500 chickens. The four traits were egg weight with a heritability of 0.51, egg production with a heritability of 0.22, age at first egg with a heritability of 0.41 and body weight with a heritability of 0.55. Firstly, each of these traits were selected for independently using the first four selection methods and secondly the traits were selected for two at a time using index selection. The most significant results obtained from the single trait simulations were that for all traits family-index selection produced the best response to selection in the initial generations and between family selection produced the best response in the later generations. The traits with a higher heritability (egg weight and body weight) responded better to individual selection than they did to within family selection and between family selection in the initial generations. However, within family selection and between family selection proved to be more effective for traits with a low heritability such as egg production. Individual selection and family-index selection resulted in a very rapid decline in the standard deviation of all the traits. Between family selection resulted in the slowest drop in the standard deviation of all the traits, which is why this technique produced the best responses to selection in the later generations. The impact of the correlations between the economically important traits were evident from the results of index selection. For example, egg production is negatively correlated with egg weight making it difficult to gain a correlated response in both these traits simultaneously. Furthermore, egg production is negatively correlated with age at first egg implying that early maturing birds will lay more eggs, however, these eggs will be lighter. The majority of the results obtained were to be expected. Family-index selection takes all the information about an individual's breeding value into account resulting in this method of selection consistently identifying the most desirable individuals being selected. It is therefore the preferred method of selection under all circumstances. It is, however, often not economically and practically efficient to incorporate this technique and the use of another method of selection usually proves to be more beneficial. Individual selection proved to be most effective when applied to traits with high heritabilities, due to the fact that this method selects individuals based on their own phenotypic values. For traits with a high heritability, an individual with a good phenotypic value will have a good breeding value. Between family selection and within family selection proved better for traits with lower heritabilities. For traits with a low heritability the phenotypic value of an individual is a poor indicator of its breeding value. Information from a number of relatives may thus improve the accuracy of prediction of the breeding value by accounting for the influence of environmental effects. The use of computer models to simulate the selection techniques proved very successful in illustrating the effectiveness of the different selection techniques under various genetic and environmental conditions. The models may also prove to be very effective from an educational perspective. / Thesis (M.Sc.)-University of Natal, Pietemaritzburg, 2003.

Assignment (MPhil)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The study conducted was aiming on evaluating the influence of different levels of energy and amino acids, mainly lysine and methionine, on production performance of the layer bird. There were three treatments, namely the Control diet, a high energy, lysine and methionine diet (High spec.) and a low energy, lysine and methionine diet (Low spec.). The energy levels were 11.2 MJ/kg, 11.5 MJ/kg and 10.9 MJ/kg respectively. Lysine levels were 0.67%, 0.73% and 0.63% whereas methionine levels were 0.36%, 0.38% and 0.34% respectively. The experimental design was 3 x 4 factorial, which is 3 treatments with 4 replicates each. Results showed no significant difference (P>0.05) between treatments in egg production, egg mass, egg output, bodyweight and mortality. Feed intakes of the High spec. diet were significantly lower (P<0.05) than that of the control diet and the Low spec. diet. / AFRIKAANSE OPSOMMING: Hierdie studiestuk handeloor die evaluering van die invloed wat die verskillende vlakke van die energie en aminosure, veraiiisien en methionine op die produksie van 'n lê hoender het. Daar was gebruik gemaak van drie behandelings, naamlik die kontrole dieet, 'n hoë energie, lisien en methionien dieet (Hoë spesifikasie), en 'n lae energie, lisien en methionien dieet (Lae spesifikasie). Die energievlakke was 11.2 MJ/kg, 11.5 MJ/kg en 10.9 MJ/kg onderskeidelik. Lisienvlakke was 0.67%, 0.73% en 0.63% waarby methionienvlakke was 0.36%, 0.38% and 0.34% onderskeidelik. Die eksperimentele ontwerp was 3 x 4 fakulteitsfunksies: 3 behandelings met 4 replikas elk. Die resultate het geen noemenswaardige verskille (P>0.05) tussen die behandelinge in eierproduksie, eiergewig, eier-uitset, liggaamsgewig en mortaliteite nie. Die voerinnames van die hoë spesifikasie dieet was aansienlik laer (P<0.05) as die van die kontrole en lae spesifikasie dieet.

Bulletin No. 145 Revised; Revised by H. Embleton

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Revised

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