CORRELATIONS BETWEEN SOMATIC CELL COUNT AND PHYSICAL-CHEMICAL PARAMETERS AND MICROBIOLOGY OF MILK QUALITY

Abstract

The study aimed to evaluate the correlations between somatic cell count (SCC) and milk components, and verify the associations of environmental conditions with SCC. Data were obtained from 1,541 dairy farms located in 15 municipalities in the dairy region of Vale do Taquari, Rio Grande do Sul. The data from SCC, total bacterial count (TBC) and milk composition, from June 2008 to December 2011, were tabulated, totaling 44,089 samples. The environment temperature showed positive and significant correlation with the somatic cell score, while rainfall and air relative humidity showed no correlation. The fat, protein, minerals and total solids were directly correlated with the SCC, while non-fat-solids and lactose showed an opposite behavior. By the principal component analysis (PCA) followed by the agglomerative hierarchical clustering method, the seven treatments in the present study were reduced to five groups according to the similarity, showing that milk with SCC above 400,000 to 750,000 cels mL^-1 present the same quality, not justifying the interval stratification within this range of variation.

KEYWORDS: climatic variables; mastitis; milk chemical quality; milk composition; milk hygienic-sanitary quality.