Estimation of the milk production function : application of the incomplete gamma function in the São Miguel Island (Azores)

• Autor(a) principal: Silva, Francisco
• Data de Publicação: 2011
• Outros Autores: Batista, Maria da Graça Câmara, Ponte, Rui Alexandre Viveiros
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.3/4964
• topic: Incomplete Gamma Function; Income Estimation; Production Estimation

The Incomplete Gamma Function was used to explain the behavior of 305 days of lactation of dairy cows on São Miguel Island in the Azores. Ultimately, 330,127 observations of the daily production of these animals were used to estimate the production functions and income per animal of each lactation. Lactations were checked, as were the months of cow calving that maximized production and income for each lactation. The conclusion was that the fourth and fifth lactations maximized the income and production per animal for the 305 days of production. The calving between the months of October and December was shown to maximize the accumulated production of lactation whereas calving between the months of August and December contributed to maximizing the accumulated income per lactation. The management of livestock directed toward the maximization of the income of the dairy farm must take into account that insemination of these animals will have to take place between the months of December and March so that calving can occur in the intended months and lactation can start at the time of the year conductive to optimal income. The management of livestock lactation of a dairy farm on São Miguel Island demonstrated that it was possible to increase production and income per animal by up to 25%, while the management of calving months was shown to also maximize production and income per animal by up to 9%. However, the low adjustment value of the model (R2 of 25%) pointed to the weak adaptation of the Incomplete Gamma Function to the data used.