Variation in somatic cell count and milk components in fraction collected quarter milk samples

Milk components secretion into milk are following different routes. In the mammary gland; protein, fat and Lactose are synthesised in the epithelial cells and released into the alveoli, somatic cells enter the milk by intracellular migration. Cisternal milk should be avoided when Somatic Cell count (SCC) analysis and bacteriological examination are being preformed (IDF 1984). Dairy advisory should be based on adequate knowledge in using SCC as a management toot and thus helping farmers in controlling udder health, deciding mastitis therapy and selecting the right cows for dry cow therapy or cutting. The representative of SCC in single milk fractions of quarter milk samples were therefore analysed. The quarter milk samples were sampled from 7 Norwegian Red Cattle by catheter drainage in fractions of 120 mL, 20 samples were taken. Fraction samples were analysed for protein, fat and Lactose by Milcoscan 605 and somatic cell count by Fossomatic 360. The results showed large variations in SCC (approximately 100.000 cells/mL to 1-2.000.000 cells/mL) in different fractions. Samples from cows with low SCC (Less than 50.000 - 100.000) did not show variation of great practical importance compared to cows with high SCC. Milk fractions with high SCC tended to show decreased Lactose values. The results indicated that SCC measured in one single milk fraction, from clinical healthy cows, should be carefully interpreted and inflammatory reactions in single milk fractions were observed. SCC should be measured in milk samples representative for the entire udder- or quarter milk. The Health Periodical from the Norwegian Cattle Health Services contains such information.