AVALIAÇÃO DE INDICADORES ZOOTÉCNICOS E ECONÔMICOS EM SISTEMAS LEITEIROS COM DIFERENTES ESTRATOS DE TAMANHO.

The main animal science indexes, components of production costs and main economic indicators were assessed in dairy plantation in the north of the state of Minas Gerais, with different size layers. Data division was undertaken by nonsupervised method following the total number of cows in the herd. Coefficients of linear co-relationship, economic indexes, production costs, regression parameters of variables with significant co-relationship with profit were determined. Zootechnical indexes with the greatest influence in unit costs of production comprised percentage of milking cows, mean number of milking days, mean productivity of the herd, efficiency of labor and productivity per area. Birth intervals had a significant corelationship with gross and net margins per liter of virtual milk. Percentage of milking cows, productivity of milking animals and productivity per area had the greatest coefficient of co-relationship with profit. In the case of regression, zootechnical indexes milking cow percentage and productivity of milking cows provided negative rates for the interception point of the dependent variable profit. Results show that layers with greater productivity had lower operational costs and less net margin. The above did not affect significant rates in profit. [ABSTRACT FROM AUTHOR]