Variávéis relacionadas ao teor de extrato seco desengordurado em amostras de leite de tanques de resfriamento de estabelecimentos rurais

Abstract

The defatted dry extract (DDE) comprises of the solid constituents of the milk, except for the fat, and must have a minimum established content of 8.4% for raw milk in Brazil. The objective was to evaluate the effects of commercialized milk volume, somatic cell count (SCC) and total bacterial count (TBC) on the DDE content of dairy farm milk samples. The sampling included data from monthly milk analyzes of dairy farms, which supply four dairy industries located in the state of Santa Catarina, Paraná and Rio Grande do Sul, and comprised of 106.470 observations sampled in 2015.The data were submitted to variance and regression analysis. To evaluate the influence of the volume of milk commercialized by the farmers, the SCC and TBC levels, and the levels of DDE, the values of these explanatory variables were stratified in quintiles. The mean DDE was 8.55%, with 25.6% of the samples being below the established minimum. In regard to the volume of milk marketed by the farmers, seasonal variations were observed in all quintiles of dairy farms analyzed, but with lower levels of DDE in milk samples from small farms throughout the year. Samples of milk with high TBC and, especially high SCC, presented lower percentage of DDE during the year. It is concluded that the DDE content of milk is related to the season of the year, the production volume per dairy, SCC and TBC.