Utjecaj sezone na kemijski sastav mlijeka i broj somatskih stanica.

The aim of our research was to establish the influence of the season on the chemical composition of bulk tank cow’s milk and the somatic cell count in it. The bulk tank cow’s milk samples were collected daily during a period of one year. When the milk was brought to the dairy in special tanks, before pouring bulk tank milk, samples were taken that we marked as «tours». Milk samples were taken in three tours from the tanks every seven days, and 144 tours were processed in total. Comparing chemical indicators of milk quality, milk fat levels were significantly higher in the winter and the autumn (P0.05), and the highest levels were registered during the winter. Lactose level was significantly higher during the winter and the spring (P<0.05), and the NFDM (non fat dry matter) was significantly lower in the summer, in comparison to the other seasons (P<0.05). Determining the somatic cell count (SCC) in the bulk tank cow’s milk samples, we established that during the winter the somatic cell count was significantly higher in comparison to the other seasons (P<0.05). However, we did not determine significant, high or positive correlations between the chemical composition of the milk and the somatic cell count in either of the seasons. Based on the results of our research, we concluded that the season has an influence on the somatic cell count and the chemical composition of fresh cow’s milk, but not on the correlations between them.Cilj istraživanja bio je utvrditi utječe li godišnje doba na kemijski sastav mlijeka i broj somatskih stanica u njemu. Mlijeko je tijekom godine dana sakupljano svaki dan. Pri dolasku mlijeka u mljekaru posebnim cisternama prije istakanja uzimani su uzorci. Uzorci mlijeka uzimani su iz cisterne svakih sedam dana od tri dopremljene količine. Ukupno je bilo obrađeno 144 dopremljenih količina. Usporedbom kemijskih pokazatelja kakvoće mlijeka razina masti bila je značajno veća zimi i u jesen (P<0,05) u odnosu na proljeće i ljeto. Vrijednosti proteina značajno su se razlikovale među godišnjim dobima (P>0,05), a najviša razina zabilježena je zimi. Razina laktoze bila je značajno veća zimi i u proljeće (P<0,05), a vrijednosti BST-a bile su značajno niže ljeti u odnosu na druga godišnja doba (P<0,05). Određujući broj somatskih stanica u mlijeku zimi je zabilježen značajno veći (P