Modelagem de uma unidade de produção para caprinos leiteiros utilizando a dinâmica de sistemas

• Ano de defesa: 2007
• Autor(a) principal: Guimarães, Vinicius Pereira
• Orientador(a): Rodrigues, Marcelo Teixeira
• Banca de defesa: Braga, Marcelo José , Borges, Iran
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Zootecnia
• Departamento: Genética e Melhoramento de Animais Domésticos; Nutrição e Alimentação Animal; Pastagens e Forragicul
• País: BR
• Palavras-chave em Português: Pensamento sistêmico; Sistemas de produção; Avaliação econômica
• Palavras-chave em Inglês: Systemic thinking; Production systems; Economic evaluation
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL
• Link de acesso: http://locus.ufv.br/handle/123456789/1682

The study was developed approaching characteristics of dynamic, complexity and interrelationship in a dairy goat farm. Through the methodology of modeling and simulation called System Dynamics, were tried to identify the impacts in dynamics and profitability in dairy goats herds caused by modifications in reproduction, mortality, feed quality and the age at the beginning of the reproductive life, besides of considering the methodology as a tool for decision making, looking for better understanding and improving the knowledge of complex systems. Produced by Ventana Systems®, the program Vensim was used because it is a free program and has enough functions to develop the work. Initially was created a functional framework of herd dynamics, with the evolution of animals since birth until culling. This dynamics was built in a chronological sequence of events since birth, going to the growing up phase, gestation, and kidding. For the parameterization of the system was assumed average values from the extension service of the Federal University of Viçosa, Brazil. The time unit used in the study was months and the time step between each simulation was 0.03123 months (22.5 hours). The total time, for all the simulations, was 10 years or 120 months. Was verified that changing reproductive aspects in a herd, as fertility rates and number of breeding seasons, the impacts in herd dynamics and in the profitability of the system are considerable. The mortality rates, mainly in the first phase of the animal s life, also had a great impact over the system. One of the most important issues in the current production systems is the impact of the age at first mating due to, the bigger is this age, slower is the growing up capacity of the herd and smaller is the profitability of the system. Another important point that needs attention was the comparison of systems according to feed quality and genotypes with different nutritional requirements. The results showed that the efficient equation of the binomial genotype- feed will determine better productivity and mainly better profitability of the system. The simulation considering males sales for meat production and assuming an existent market (consumers), paying an adequate price, could become an interesting source of income for the producers. The relative facility of developing a model, the reduction of costs with experimentation, the possibility to make sensitivity analysis, associated to clear results, are strengths of simulations based in System Dynamics. Therefore, the System Dynamics approach gives a demonstration of being an important tool to add the conventional methods of simulation.