Lactose and its relationship with other milk constituents, somatic cell count, and total bacterial count

•Lactose interferes with the formation of clusters.•Somatic cell count reduces the lactose content in milk.•Lactose is negatively influenced by total bacterial count.•The fat and protein content are not related to lactose. Lactose has an essential role in milk synthesis, and low lactose content adversely affects dairy product yield. In this study, the association between milk lactose content and other milk constituents (protein and fat), somatic cell count (SCC), and total bacteria count (TBC) was valuated using a database of bulk tank milk (BTM) samples from dairy farms in southern Brazil. Factor and cluster analysis were performed on a dataset containing the fat, protein, and lactose contents, SCC, and TBC of 154,781 BTM samples evaluated by the State Laboratory of Milk Quality (LABLEITE). The factor analysis showed that lactose content in milk was positively associated with fat and protein contents as well as negatively associated with SCC and TBC. The cluster analysis on three clusters showed differences in the fat and protein contents of the BTM samples (P