The South African broiler industry is the greatest contributor to the South African agricultural sector, while at the same time providing the cheapest form of protein to the South African consumer. In light of a recent application for increased tariffs due to the industry’s inability to compete with the price of imported products, the need for a tool that is able to quantify the benefit of increased tariff protection to producers, while at the same time considering the cost of increased tariffs on South African consumers became apparent. The integrated nature of the industry however raised the concern that the assumptions associated with traditional quantitative modelling techniques, particularly that of a perfectly competitive market, would not allow the current broiler model within the BFAP sector modelling framework to represent the industry accurately. The primary objective of the study was to determine the true method of price discovery within the South African broiler market, in order to specify a price equation that is able to capture the dynamics surrounding price formation with improved accuracy. This price formation mechanism was then integrated into a simulation model that represents the industry accurately. Due to its ability to represent reality within the market with greater accuracy, the New Institutional Economic (NIE) framework was used to analyse the structure of the South African broiler industry as action domain. The actors and activities in the value chain were evaluated, followed by an analysis of the institutions that govern exchange within the market, highlighting the implications of these institutions for price formation within this coordinated market structure. Upon evaluation of compensation structures used within broiler production contracts, it became evident that the market for live broilers produced by contract growers could be considered as a market for grower services, as opposed to a market for live broilers. Compensation based on a broiler production tournament offers significant incentives for greater efficiency, effectively ensuring that production efficiency increases on a continuous basis. Despite the contractual obligation of integrated producers to pay their contracted growers based on a formula including the cost of production, the broiler producer price is negotiated between integrators and retailer, within a concentrated market structure. The cost of production is used as bargaining tool in price negotiations, yet the availability of imported products at extremely competitive prices limits the extent to which increased production costs can be passed up through the value chain. This was confirmed by the fact that the response of the domestic broiler producer price was much more elastic to changes in the international price than to changes in feed costs. The theoretical factors that drive broiler producer prices in South Africa were confirmed econometrically through the use of an error correction model, estimated empirically using secondary monthly data from 2007 to 2012. The estimated equations were integrated into a partial equilibrium framework using an import identity to establish equilibrium in the market, rather than a price equilibrator. The inelastic response from the domestic broiler producer price to changes in broiler feed prices raised questions regarding South African producers’ ability to compete with imported products and produce sustainably in the long run. Given the higher costs of production domestically, as well as the relative size and importance of the broiler industry within the South African agricultural sector, the need to evaluate the tariff application objectively was clear. Policy decisions should weigh the benefit of increased producer prices on broiler producers against the cost of protective policy to consumers, while also considering the specific consumers that would be required to bear the cost of increased tariffs. Integration of the partial equilibrium model of the broiler industry into the BFAP sector modelling framework enabled the simulation of various tariff scenarios, quantifying the effect on the agricultural sector, as well as chicken consumption. At the same time, the successful simulation of different scenarios and policy shocks validated the model. Simulation of the tariffs applied for by SAPA resulted in a producer price increase of 6%, which would be a significant margin on the bottom line for domestic producers. The cost to consumers of a 3.3% increase in retail prices also seems digestible; however the underlying factors that drive competitiveness should also be addressed in order to ensure long run sustainability for the industry. / Dissertation (MSc Agric)--University of Pretoria, 2013. / gm2014 / Agricultural Economics, Extension and Rural Development / unrestricted

Orientador: Daniella Jorge de Moura / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-17T14:08:00Z (GMT). No. of bitstreams: 1 Lima_KarlaAndreaOliveirade_D.pdf: 5594209 bytes, checksum: 2fd1cc47487130c9ee71f42506d49d72 (MD5) Previous issue date: 2011 / Resumo: A produção de gases no interior de galpões e suas emissões estão intimamente ligados ao microclima estabelecido no galpão pela sua temperatura, umidade e velocidade do ar. Sendo assim, o ambiente gerado no galpão, é por sua vez influenciado pela tipologia construtiva dos galpões e pelo sistema de ventilação. Este trabalho teve por objetivo geral avaliar os ambientes aéreo e térmico de galpões visando caracterizar as condições de criação de frango de corte, com base na qualidade da cama e do ar, gerados em galpões com ventilação mecânica positiva e negativa. Este projeto foi realizado em três granjas localizadas no estado de São Paulo pertencentes a duas integradoras distintas, onde oito aviários, sendo 4 do tipo pressão positiva e 4 do tipo do tipo pressão negativa, chamados de Blue house e Dark house. Foram avaliados Nestes galpões foi realizado o monitoramento das variáveis climáticas, a performance dos sistemas de ventilação utilizados, os níveis de concentração e emissão da amônia e dióxido de carbono, as condições da cama, seu pH, umidade, temperatura e condição microbiológica e serão correlacionadas a qualidade da cama gerada com a porcentagem de problemas locomotores e mortalidade dos lotes criados em galpões com ventilação mecânica positiva e negativa, em lotes com cama nova e reutilizada. Os resultados mostraram a influência dos galpões de pressão negativa na taxa de emissão de gases, CO2 e NH3 devido às suas maiores taxas de ventilação com valores que variaram de 0,25 - 0,51 gNH3/ave/dia e 387 a 907 KgCO2/galpão/dia. De acordo com o tipo de cama, se nova ou reutilizada os valores de emissão foram mais baixos para os galpões com cama nova, mesmo quando comparado os sistemas dentre si, p-valor <0,05. Os sistemas de ventilação negativa apresentaram maior consumo energético caracterizado pela potência dos seus exaustores e pelo manejo da ventilação constantemente usada durante todo o ciclo de criação. Os galpões não apresentaram diferenças estatisticamente significativas entre os seus dados zootécnicos o que caracterizou que o manejo adotado pelas integradoras foi satisfatório à produção. Através desta avaliação foi possível observar a distinção entre os sistemas de ventilação positiva e negativa quanto à emissão de gases, ao consumo energético e a sua produtividade e a viabilidade do sistema de pressão negativa na produção de frangos de corte. / Abstract: Gases production and its emission in broilers housing are related to the microclimate established in terms of temperature, humidity and air speed inside the housing. So, the environment generated in the housing is influenced by the constructive characteristics of the barn and by the adopted ventilation system. This work had as general objective to evaluate aerial and thermal environments of broiler housings aiming to characterize the conditions of broiler production, looking for the litter and air quality generated in barns with positive and negative ventilation systems. This project was carried out in three farms located in São Paulo State, under two different integrator companies responsible for the flocks management. In the total eight broiler houses were evaluated being four houses named positive pressure and four named negative pressure. Both systems were mechanically ventilated systems. Climatic variables, the performance of ventilation systems, gases concentration levels and emissions were monitored in these houses. Further research was carried out about the litter condition, its pH, humidity, temperature and its correlation between litter quality and mortality and lameness incidence on the flocks The results showed the influence of the negative pressure systems on the, CO2 and NH3 emission rate due to their higher ventilation rates with values ranging from 0.25 to 0.51 and from 387 to 907 gNH3/bird/day and KgCO2 /house /day. The emissions rates were lower according to the type of litter, new or built-up even when compared among the systems themselves, p-value <0.05. Negative pressure systems had higher energy consumption characterized by the power of exhausters motor and ventilation management that was constantly running throughout the growing period. The broiler houses showed no statistically significant differences between their data production that means that management adopted by integrator companies was satisfactory. Through this assessment it was possible to observe the distinction between the positive and negative ventilation systems on the emissions rates, energy consumption and its productivity where it was also noticed the viability of the negative pressure system in the broilers production. / Doutorado / Construções Rurais e Ambiencia / Doutor em Engenharia Agrícola

Thesis (M. Tech.) -- Central University of Technology, Free State, 2007 / Four different South African indigenous (Naked Neck (NN), Ovambo (OVB), Venda (VD) and Potchefstroom Koekoek (PK) chicken breeds were used in this study. From each of the four breeds of chicken, 40 hens and 8 cocks were selected randomly. Two groups each of sixteen cocks were subsequently formed: high performing (HP) and low performing (LP) groups to determine the relationships between cock semen viability and the fertility of artificially inseminated South African indigenous layer breeds. Semen was collected following five minutes of sexual massage (5SM) and evaluated for semen volume (ml), sperm motility (%), live sperm (%) and total sperm (x109/ml). Semen from each cock was then used to inseminate five hens per breed, in each treatment. Each hen was inseminated twice a week throughout the duration of the trial. During the experimental period, each hen was inseminated with 0.05 ml diluted semen. The artificially inseminated hens were examined for average egg weight (g), fertility (%), hatchability of set eggs (%), live chicks (%), normal chicks (%) and chick weight (g). A total of 1600 eggs, i.e. 400 eggs from each breed were collected in three batches following artificial insemination from individually caged hens and were hatched to compare hatching parameters among breeds. The hatchability traits of hens of the four breeds (NN, OVB, PK and VD) were compared. Hatching egg weight had significant (P < 0.05) difference among the four breeds. The results of this study indicate that semen viability exemplified by ejaculate volume, sperm motility; live sperm and total sperm per ejaculate were significantly (P < 0.01) superior in the HP cocks compared to the LP cocks. Hens inseminated with semen from the HP cocks in each experimental group resulted in higher egg weight (g), fertility (%), hatchability of set eggs (%), live chicks (%), normal chicks (%) and chick weight (g). Significant positive relationships existed between semen volume and sperm motility (P < 0.05), semen volume and live sperm cells (P < 0.01), semen volume and total sperm (P < 0.01) in NN, OVB and VD, with negative correlations in PK. Some positive correlations were found between sperm motility and live spermatozoa (P < 0.01), sperm motility and total sperm (P < 0.01), live sperm and total sperm (P< 0.01) in NN, OVB, PK and VND. Fertility was the highest in the HP group. Fertility was also the highest in PK, intermediate and similar in OVB and NN and lowest in VD (P<0.05). Breed had a significant effect on hatchability of fertile eggs (P<0.05). Hatchability of total eggs set was highest in PK and NN, intermediate in OVB and lowest in VD (P<0.05). Breed had a significant effect on live, normal chicks and chick weight (P<0.05). Live chick was the highest in NN, whereas at day-old, normal chick and chick weight at hatching were the highest (23.50 ± 0.11) (P<0.05) in PK (98.14 ± 0.67 vs. 37.90 ± 0.28 g), intermediate and similar in NN (87.90 ± 0.63 vs. 23.50 ± 0.11) and OVB (87.75 ± 0.45 vs. 32.81 ± 0.49 g) and the lowest but with an acceptable value in VD (76.85 ± 0.46 vs. 26.90 ± 0.36 g). There were some correlations among different hatchability traits depending on breed. The correlations were more profound among PK. It was clear that chick weight as percent of egg weight was not just a function of egg weight, and that genotype also played an important role favouring the heavier breeds. The results obtained in this study on the relationships between cock semen viability and the fertility of artificially inseminated South African indigenous layer breeds elucidate that the use of high performing (HP) cocks following five minutes of sexual massage, prior to semen collection and artificial insemination of layers is a practical method for optimising sperm viability and subsequent fertility of hens. The results of this study suggest that the Potchefstroom Koekoek (PK) cocks and hens are superior to the Naked Necks (NN), Ovambo (OVB) and Venda (VD). The Ovambo and Naked Neck cocks ranked second in donating quality semen as well as in improving the fertility and hatchability traits of the indigenous chicken breeds. Thus selection of high performing cocks through five minutes sexual massage prior to semen collection and use is recommended for poultry AI breeding programmes.

A suspeita de indução de resistência bacteriana a antibióticos melhoradores de desempenho (AMD) e a pressão dos consumidores e dos mercados importadores para a abolição da prática criam a necessidade da descoberta de novas substâncias que funcionem como substitutos aos antibióticos, como os probióticos, prebióticos e simbióticos. Sendo assim, o objetivo deste trabalho foi avaliar os efeitos de probiótico, prebiótico e simbiótico sobre o desempenho zootécnico, os rendimentos de carcaça e de cortes e a morfologia intestinal de frangos de cortes criados de 1 a 43 dias de idade. Foram utilizados 1200 pintos de 1 dia, machos, da linhagem comercial Cobb 500®, distribuídos em delineamento inteiramente casualizado, com 5 dietas experimentais: Controle, Antibiótico (virginiamicina), Probiótico (Bacillus subtilis), Prebiótico (mananoligossacarídeo - parede celular de Saccharomyces cerevisae) e Simbiótico (Bacillus subtilis + mananoligossacarídeo - parede celular de Saccharomyces cerevisae) e 8 repetições de 30 aves cada. Em relação ao desempenho zootécnico, os aditivos testados provaram ser alternativas viáveis ao antibiótico melhorador de desempenho utilizado, uma vez que apresentaram resultados melhores que os do grupo controle e iguais aos obtidos com o uso do AMD. Da mesma maneira, para os rendimentos de carcaça e de cortes, o probiótico, o prebiótico e o simbiótico, mostraram poder ser usados como substitutos ao antibiótico, uma vez que promoveram rendimentos iguais aos do grupo alimentado com AMD. Por fim, para a morfometria intestinal, os dados obtidos mostram não haver uma relação direta entre a presença de aditivo e uma maior altura de vilosidade, menor profundidade de cripta ou maior relação vilo:cripta, uma vez que nem sempre os animais suplementados tiveram melhores resultados que o grupo controle negativo. Desta maneira concluí-se que os aditivos usados podem substituír o antimicrobiano testado, em suas respectivas doses, para as fases de criação consideradas, uma vez que fornecem resultados tão bons quanto aos obtidos com o AMD. / The suspect of the resistance\'s indution of antibiotics (ATB) and the pressure of the consumers and of the importing markets for the abolishment of this kind of practice have criated the necessity of discovering new substances that work like substitutes to antibiotics, just like probiotics, prebiotics and symbiotcs. In this manner, the objective of this study it was evaluate the effects of probiotic, prebiotic and symbiotic on performance, carcass and parts yield and intestinal morphology of broilers from 1 to 43 days of age. There were used 1,200 one-day-old chicks, male, Cobb 500® strain, distributed on a completely randomized design, with 5 experimental diets: Control, Antibiotic (virginiamicin), Probiotic (Bacillus subtilis), Prebiotic (Saccharomyces cerevisae yeast cell) and Symbiotic (Bacillus subtilis + Saccharomyces cerevisae yeast cell) and 8 replicates with 30 chicks each one. Concernig on the performance, the tested additives have been proved to be viable alternatives to used antibiotic, once that they have showed better results than the control group, and similars to the ones that were obtained with the use of antibiotic (ATB). Equally, for the carcass and parts yield, probiotic, prebiotic and symbiotic have showed they can be used like substitutes to antibiotics, once they have promoted equall yields to the group fed antibiotic. At last, for the intestinal morphology, the data haven\'t showed relation between the additive\'s presence and a higher vilo high, a smaller cript depth and a higher vilo:cript ratio, once not always animals fed additives have had better results than the control group. This way, the conclusion is that the substitution of the antimicrobian by the additives, in its respective doses, can be adopted once promotes good results as the antibiotic.

Made available in DSpace on 2017-05-12T14:46:56Z (GMT). No. of bitstreams: 1 Fernanda Catelan.pdf: 917807 bytes, checksum: 1eb69893664d6f85f570a2e83ee5cc80 (MD5) Previous issue date: 2007-02-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The general aim of this research was to study the effects of different heating systems on the bioeconomic development of broilers from day 1 to day 45. The experiment was carried out during the winter of 2005, in commercial broiler houses located in western Paraná. The research was developed in a 1200 m2 broiler houses, with male broilers, from three different breedings, in the period between birth and slaughter on day 45, for each analyzed treatment. The adopted treatments for the economic evaluation of the different heating systems were automatic wood-burning system and automatic infrared gas system. The economic evaluation was made analyzing the energy consumption by the heaters in each treatment the gas the wood-burning through the bioeconomic index and the gross margin. The zootechnical indexes, which were evaluated, were the average weight gain and the feed consumption. The statistical data evaluation was by a randomized block in a factorial 2 X 3 model, two heating systems (automatic wood-burning and automatic infrared gas systems), three breedings broilers (A, B, C), made up by six treatments and six repetitions, totaling thirty-six broiler houses with thirteen thousand three hundred (13.300) birds each. The averages were analyzed by the Tukey test. For the general analyses of the results the Software Statistic® was utilized. The results showed that, in relation to energy consumption, the wood-burning system presented a higher energy consumption due to the lower heating power of wood, compared to the infrared gas system. Although the gas system has exhibited a higher production cost, it is still being used by the business owners. There was not a significant difference for the gross margin values and the bioeconomic index worked out for the different treatments. / O objetivo geral desta pesquisa foi o de estudar o efeito de diferentes sistemas de aquecimento sobre o desempenho bioeconômico de frangos de corte de um a 45 dias. O experimento foi realizado no período de inverno de 2005, em propriedades de produção industrial de frangos de corte, localizada no oeste do estado do Paraná. A pesquisa foi desenvolvida em aviários de 1200 m2, com frangos machos, de três linhagens diferentes, entre o nascimento e abate aos 45 dias, para cada tratamento estudado. Os tratamentos adotados para a avaliação econômica dos diferentes sistemas de aquecimento foram: sistema de aquecimento automático infravermelho a gás e sistema de aquecimento automático a lenha. A avaliação econômica foi realizada por meio de consumo de energia pelos aquecedores, a lenha e a gás, através da margem bruta e índice bioeconômico. Os índices zootécnicos avaliados foram: ganho médio de peso e consumo de ração. A avaliação estatística dos dados foi realizada, considerando o delineamento em blocos ao acaso em um modelo fatorial 2 x 3, dois sistemas de aquecimento (sistema de aquecimento automático infravermelho a gás e sistema de aquecimento automático a lenha), três linhagens de pintos machos (A, B e C), composto por seis tratamentos e seis repetições, perfazendo um total de 36 aviários com treze mil e trezentas (13.300) aves cada um. As médias foram analisadas através do teste de Tukey. Para a análise geral dos resultados, foi utilizado o Software Statistic®. Os resultados mostram que, em relação ao consumo energético, o sistema de aquecimento a lenha teve o maior consumo de energia, isso ocorre devido ao menor poder calorífico da lenha, em relação ao GLP. Porém, o sistema a gás apresentou maior custo de produção, mas continua sendo utilizado pelos avicultores. Não houve diferença significativa para os valores de margem bruta e para o índice-bioeconômico calculados para os diferentes tratamentos.

A suspeita de indução de resistência bacteriana a antibióticos melhoradores de desempenho (AMD) e a pressão dos consumidores e dos mercados importadores para a abolição da prática criam a necessidade da descoberta de novas substâncias que funcionem como substitutos aos antibióticos, como os probióticos, prebióticos e simbióticos. Sendo assim, o objetivo deste trabalho foi avaliar os efeitos de probiótico, prebiótico e simbiótico sobre o desempenho zootécnico, os rendimentos de carcaça e de cortes e a morfologia intestinal de frangos de cortes criados de 1 a 43 dias de idade. Foram utilizados 1200 pintos de 1 dia, machos, da linhagem comercial Cobb 500®, distribuídos em delineamento inteiramente casualizado, com 5 dietas experimentais: Controle, Antibiótico (virginiamicina), Probiótico (Bacillus subtilis), Prebiótico (mananoligossacarídeo - parede celular de Saccharomyces cerevisae) e Simbiótico (Bacillus subtilis + mananoligossacarídeo - parede celular de Saccharomyces cerevisae) e 8 repetições de 30 aves cada. Em relação ao desempenho zootécnico, os aditivos testados provaram ser alternativas viáveis ao antibiótico melhorador de desempenho utilizado, uma vez que apresentaram resultados melhores que os do grupo controle e iguais aos obtidos com o uso do AMD. Da mesma maneira, para os rendimentos de carcaça e de cortes, o probiótico, o prebiótico e o simbiótico, mostraram poder ser usados como substitutos ao antibiótico, uma vez que promoveram rendimentos iguais aos do grupo alimentado com AMD. Por fim, para a morfometria intestinal, os dados obtidos mostram não haver uma relação direta entre a presença de aditivo e uma maior altura de vilosidade, menor profundidade de cripta ou maior relação vilo:cripta, uma vez que nem sempre os animais suplementados tiveram melhores resultados que o grupo controle negativo. Desta maneira concluí-se que os aditivos usados podem substituír o antimicrobiano testado, em suas respectivas doses, para as fases de criação consideradas, uma vez que fornecem resultados tão bons quanto aos obtidos com o AMD. / The suspect of the resistance\'s indution of antibiotics (ATB) and the pressure of the consumers and of the importing markets for the abolishment of this kind of practice have criated the necessity of discovering new substances that work like substitutes to antibiotics, just like probiotics, prebiotics and symbiotcs. In this manner, the objective of this study it was evaluate the effects of probiotic, prebiotic and symbiotic on performance, carcass and parts yield and intestinal morphology of broilers from 1 to 43 days of age. There were used 1,200 one-day-old chicks, male, Cobb 500® strain, distributed on a completely randomized design, with 5 experimental diets: Control, Antibiotic (virginiamicin), Probiotic (Bacillus subtilis), Prebiotic (Saccharomyces cerevisae yeast cell) and Symbiotic (Bacillus subtilis + Saccharomyces cerevisae yeast cell) and 8 replicates with 30 chicks each one. Concernig on the performance, the tested additives have been proved to be viable alternatives to used antibiotic, once that they have showed better results than the control group, and similars to the ones that were obtained with the use of antibiotic (ATB). Equally, for the carcass and parts yield, probiotic, prebiotic and symbiotic have showed they can be used like substitutes to antibiotics, once they have promoted equall yields to the group fed antibiotic. At last, for the intestinal morphology, the data haven\'t showed relation between the additive\'s presence and a higher vilo high, a smaller cript depth and a higher vilo:cript ratio, once not always animals fed additives have had better results than the control group. This way, the conclusion is that the substitution of the antimicrobian by the additives, in its respective doses, can be adopted once promotes good results as the antibiotic.

Made available in DSpace on 2017-07-10T19:23:43Z (GMT). No. of bitstreams: 1 Fernanda Catelan.pdf: 917807 bytes, checksum: 1eb69893664d6f85f570a2e83ee5cc80 (MD5) Previous issue date: 2007-02-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The general aim of this research was to study the effects of different heating systems on the bioeconomic development of broilers from day 1 to day 45. The experiment was carried out during the winter of 2005, in commercial broiler houses located in western Paraná. The research was developed in a 1200 m2 broiler houses, with male broilers, from three different breedings, in the period between birth and slaughter on day 45, for each analyzed treatment. The adopted treatments for the economic evaluation of the different heating systems were automatic wood-burning system and automatic infrared gas system. The economic evaluation was made analyzing the energy consumption by the heaters in each treatment the gas the wood-burning through the bioeconomic index and the gross margin. The zootechnical indexes, which were evaluated, were the average weight gain and the feed consumption. The statistical data evaluation was by a randomized block in a factorial 2 X 3 model, two heating systems (automatic wood-burning and automatic infrared gas systems), three breedings broilers (A, B, C), made up by six treatments and six repetitions, totaling thirty-six broiler houses with thirteen thousand three hundred (13.300) birds each. The averages were analyzed by the Tukey test. For the general analyses of the results the Software Statistic® was utilized. The results showed that, in relation to energy consumption, the wood-burning system presented a higher energy consumption due to the lower heating power of wood, compared to the infrared gas system. Although the gas system has exhibited a higher production cost, it is still being used by the business owners. There was not a significant difference for the gross margin values and the bioeconomic index worked out for the different treatments. / O objetivo geral desta pesquisa foi o de estudar o efeito de diferentes sistemas de aquecimento sobre o desempenho bioeconômico de frangos de corte de um a 45 dias. O experimento foi realizado no período de inverno de 2005, em propriedades de produção industrial de frangos de corte, localizada no oeste do estado do Paraná. A pesquisa foi desenvolvida em aviários de 1200 m2, com frangos machos, de três linhagens diferentes, entre o nascimento e abate aos 45 dias, para cada tratamento estudado. Os tratamentos adotados para a avaliação econômica dos diferentes sistemas de aquecimento foram: sistema de aquecimento automático infravermelho a gás e sistema de aquecimento automático a lenha. A avaliação econômica foi realizada por meio de consumo de energia pelos aquecedores, a lenha e a gás, através da margem bruta e índice bioeconômico. Os índices zootécnicos avaliados foram: ganho médio de peso e consumo de ração. A avaliação estatística dos dados foi realizada, considerando o delineamento em blocos ao acaso em um modelo fatorial 2 x 3, dois sistemas de aquecimento (sistema de aquecimento automático infravermelho a gás e sistema de aquecimento automático a lenha), três linhagens de pintos machos (A, B e C), composto por seis tratamentos e seis repetições, perfazendo um total de 36 aviários com treze mil e trezentas (13.300) aves cada um. As médias foram analisadas através do teste de Tukey. Para a análise geral dos resultados, foi utilizado o Software Statistic®. Os resultados mostram que, em relação ao consumo energético, o sistema de aquecimento a lenha teve o maior consumo de energia, isso ocorre devido ao menor poder calorífico da lenha, em relação ao GLP. Porém, o sistema a gás apresentou maior custo de produção, mas continua sendo utilizado pelos avicultores. Não houve diferença significativa para os valores de margem bruta e para o índice-bioeconômico calculados para os diferentes tratamentos.

Thesis (M.A. (Agricultural Extension)) -- University of Limpopo, 2015 / The aim of the study was to analyse the socio-economic factors affecting the gross margin of small-scale broiler producers in the Vhembe district and thereby determine their profitability and contribution towards the local economic development. The population comprised of small-scale broiler producers who reared between100 and 3200 birds in the Vhembe district. A total of 94 out of 311small-scale broiler producers were selected using a simple random- sampling procedure. Data on different socio-economic parameters was collected through personal interviews using a semi-structured questionnaire. Descriptive statistics was computed using FREQ COUNTS procedures to describe the characteristics of small-scale broiler producers. Gross margin analysis was used to calculate the profitability for small-scale broiler producers. The Multiple Linear Regression was used to estimate the influence of socio-economic factors influence on the gross margin of the small-scale broiler producers. Multiple Regression analysis indicated that small-scale broiler producers in the Vhembe district were making profit. Socio-economic variables such as age of the farmer, farming experience, flock size, training received by the farmer, market access and record keeping, educational level, household income and extension services were found to have positive correlation with the small-scale broiler producers‟ gross margin. To effectively address production constraints affecting gross margin of small-scale broiler producers, it is, therefore, fundamental to consider their socio-economic profiles.

Necrotic enteritis (NE) caused by Clostridium perfringens type A is an important bacterial enteric disease of global broiler production. However, the dynamic interactions of NE and its predisposing factors are not fully presented by current studies. By using the System Dynamics (SD) Model, the epidemiological changes in susceptible-infected-removed models of NE and avian coccidiosis and their interactions in one or multiple grow-out cycles was established; meanwhile, the growth performance was measured by the average weights of infected and non-infected populations at harvest were estimated. The SD model provided direct and persuasive outcomes of the epidemiology and ecology of NE compared with models using statistical methodology. With interventions on certain predisposing factors of management practices and medication, effects which decreased disease incidence and growth performance were observed; moreover, the leverage points obtained from interventions on certain management practices provided quantitative results which were applicable and useful for improving the broiler production.

An interview study was undertaken to explore Swedish broiler producers´ views for the potential of hops (H. lupulus L.) to reduce reliance on ionophorous coccidiostats in broiler production. The design was a mixed methodology between grounded theory and case study with a semi structured interview method. Nine producers, four using ionophorous coccidiostats and five without reliance in production accepted interview. During interviews participants were presented to research conducted with hops in production and consequences from ionophores in production. All participants thought the risk from pathogen pressure was too great to cut reliance in intensive production owed to the lower efficacy of hops. Therefore owed to how actors in the Swedish food system behave only small producers with enough economical freedom for reduced stocking densities were regarded to be able to uphold animal health with hops. Six parameters within food systems were regarded as leverage points for a potential of hops in production on a larger societal scale if encouraging a more extensive nationwide production system. Those were: purchase will, small local production, increased responsibility within trade, law, elevated consumers and research. Law was seen as a necessity to enforce all other denominators since economical in food systems tend to override social and ecological dimensions. Consequences from power struggle in food systems disfavoring producers has although resulted in a great distrust towards other system actors such as consumers, legal institutions or wholesalers. That has created a reluctance to interact with other system actors even for common goals. A stronger position to other actors in food systems was regarded as increasing a meaningful outcome from interaction. Four parameters emerged as impacting power relations in a system the most: Purchase will, contracts, own designed production and law. Favorable purchase will and law would contribute the most for increasing adaptivity for alternatives in production by impacting on power relations. No producers had observed indicators of bacterial resistance from ionophorous coccidiostat usage. Lack of research for many years in the field was troublesome for how to develop the enterprise according to participants. Especially in relation to Norway that has abolished the static use of ionophorous coccidiostats in production. About half of the participants although regarded a shift in research towards consequences from intensive production as equally important as focusing on alternative antimicrobials.