Relationship among productive and economic variables of beef cattle in Brazil / Relações entre variáveis produtivas e econômicas de bovinocultura de corte no Brasil

ABSTRACT: The present study aimed to obtain, through statistical methods, the independent variables that influence the economic and productive results of Brazilian beef cattle. Economic and productive information was collected from 106 farms in Brazil. Data collection was performed by the Instituto de Métricas Agropecuárias (Inttegra). The variable selection method used was stepwise regression followed by polynomial regression analyses. The variable beef cattle economic result showed the positive effect of disbursement per head per month and average weight gain. An average daily gain of 520 g in live weight was obtained, and this variable was influenced especially by nutrition cost. The arroba production (arroba is a unit of weight corresponding to 15kg) was influenced by the linear effect of nutrition cost and stocking rate. The variable arroba production in pasture showed a linear and positive effect of average weight gain in pasture and stocking rate in pasture. For profit per arroba, the variables nutrition cost, disbursement with pasture, and average sale price had a linear effect. The independent variables that had the greatest influence on the response variables were stocking rate, average daily weight gain, and nutrition cost. Thus, increases in investment in nutrition and stocking rate should result in higher production rates and improvements in the profitability of this activity.

RESUMO: O presente trabalho teve como objetivo obter, por meio de métodos estatísticos, quais variáveis independentes influenciam as variáveis econômicas e produtivas na bovinocultura de corte brasileira. O banco de dados utilizado foi obtido por coleta de informações econômicas e produtivas em 106 fazendas no Brasil. O método de coleta de dados foi definido pelo Instituto de Métricas Agropecuárias (Inttegra). Foram realizadas análises de seleção de variáveis pelo método Stepwise, seguido por análises de regressão múltipla. A variável resultado econômico da bovinocultura de corte teve efeito positivo do desembolso mensal por cabeça e do ganho de peso médio diário. Para o ganho de peso médio diário foi obtido um valor médio de 520 gramas, e esta variável foi influenciada principalmente pelo custeio com nutrição. Para a produção de arroba foi obtido efeito linear do custeio com nutrição e da taxa de lotação. Para a variável produção de arroba a pasto foi obtido um efeito linear e positivo do ganho médio diário de peso no pasto e da taxa de lotação no pasto. Para o lucro por arroba, as variáveis custeio com nutrição, desembolso com pastagem e preço médio de venda tiveram efeito linear. As variáveis independentes que tiveram maior influência nas variáveis resposta foram a taxa de lotação, o ganho médio diário de peso e o custeio com nutrição. Assim, aumentos no investimento em nutrição e na taxa de lotação dos animais devem resultar em maiores índices de produção e em melhorias na rentabilidade da atividade.

Região metafisária da tíbia de coelhos: uma opção para estudos dos substitutos ósseos / Metaphyseal region of the tibia of rabbits: an option for bone substitutes studies

Apresenta-se um modelo experimental de ostectomia de tíbia em coelhos para estudo de biomateriais em processos de reparação óssea. Foi realizada falha segmentar de 6mm de diâmetro na região metafisária medial proximal de tíbia de 72 coelhos as quais foram preenchidas com substituto ósseo e avaliadas clinicamente, por exame radiográfico e por meio de tomografia computadorizada feixe cônico, em diferentes tempos. Conclui-se que a metáfise medial proximal de tíbia de coelhos é adequada como modelo para estudos que avaliem o comportamento de enxertos e/ou biomateriais em falhas ósseas.

Is presented an experimental model of tibial ostectomy in rabbits to study biomaterials during bone repair process. Segmental failure of 6 mm diameter was performed in the medial proximal tibial metaphyseal region of 72 rabbits, which were filled with bone substitute and evaluated by clinical exam, X-ray, and cone beam computed tomography at different times. It is concluded that the medial proximal tibial metaphysis region of rabbits is suitable as a model for studies that evaluate the behavior of grafts and/or biomaterials on bone defects.

Região metafisária da tíbia de coelhos: uma opção para estudos dos substitutos ósseos / Metaphyseal region of the tibia of rabbits: an option for bone substitutes studies

Apresenta-se um modelo experimental de ostectomia de tíbia em coelhos para estudo de biomateriais em processos de reparação óssea. Foi realizada falha segmentar de 6mm de diâmetro na região metafisária medial proximal de tíbia de 72 coelhos as quais foram preenchidas com substituto ósseo e avaliadas clinicamente, por exame radiográfico e por meio de tomografia computadorizada feixe cônico, em diferentes tempos. Conclui-se que a metáfise medial proximal de tíbia de coelhos é adequada como modelo para estudos que avaliem o comportamento de enxertos e/ou biomateriais em falhas ósseas.

Is presented an experimental model of tibial ostectomy in rabbits to study biomaterials during bone repair process. Segmental failure of 6 mm diameter was performed in the medial proximal tibial metaphyseal region of 72 rabbits, which were filled with bone substitute and evaluated by clinical exam, X-ray, and cone beam computed tomography at different times. It is concluded that the medial proximal tibial metaphysis region of rabbits is suitable as a model for studies that evaluate the behavior of grafts and/or biomaterials on bone defects.

Tomographic imaging of fragmented cortical bone heteroimplant and methylmethacrylate in segmental bone defect of rabbit tibia.

PURPOSE: To evaluate the performance of composites consisting of fragmented cortical bone heteroimplant in association with methylmethacrylate preserved in 98% glycerin, in segmental bone defect of rabbit tibia medial metaphysis. METHODS: In this study were used twelve adult New Zealand rabbits, divided into three groups of four animals each: G30 (30 days), G60 (60 days) and G90 (90 days). The bone defects previously created in the tibia were filled with composites and both were evaluated by cone-beam computed tomography, immediately after surgery and after 30, 60, and 90 days. RESULTS: The composites fulfilled and remained in the sites of bone defects in all cases and were not registered signals of infection, migration or rejection. CONCLUSIONS: The implanted composites promoted the bone defects repair without signals of infection and/or rejection. The composites are one more option for bone defects repair.

Tomographic imaging of fragmented cortical bone heteroimplant and methylmethacrylate in segmental bone defect of rabbit tibia

PURPOSE: To evaluate the performance of composites consisting of fragmented cortical bone heteroimplant in association with methylmethacrylate preserved in 98% glycerin, in segmental bone defect of rabbit tibia medial metaphysis. METHODS: In this study were used twelve adult New Zealand rabbits, divided into three groups of four animals each: G30 (30 days), G60 (60 days) and G90 (90 days). The bone defects previously created in the tibia were filled with composites and both were evaluated by cone-beam computed tomography, immediately after surgery and after 30, 60, and 90 days. RESULTS: The composites fulfilled and remained in the sites of bone defects in all cases and were not registered signals of infection, migration or rejection. CONCLUSIONS: The implanted composites promoted the bone defects repair without signals of infection and/or rejection. The composites are one more option for bone defects repair.

Tomographic imaging of fragmented cortical bone heteroimplant and methylmethacrylate in segmental bone defect of rabbit tibia

PURPOSE: To evaluate the performance of composites consisting of fragmented cortical bone heteroimplant in association with methylmethacrylate preserved in 98% glycerin, in segmental bone defect of rabbit tibia medial metaphysis. METHODS: In this study were used twelve adult New Zealand rabbits, divided into three groups of four animals each: G30 (30 days), G60 (60 days) and G90 (90 days). The bone defects previously created in the tibia were filled with composites and both were evaluated by cone-beam computed tomography, immediately after surgery and after 30, 60, and 90 days. RESULTS: The composites fulfilled and remained in the sites of bone defects in all cases and were not registered signals of infection, migration or rejection. CONCLUSIONS: The implanted composites promoted the bone defects repair without signals of infection and/or rejection. The composites are one more option for bone defects repair. .