Quarter milking for improved detection of increased SCC

The aim of the present study was to investigate whether milk composition and milk yield are changed in relation to a moderate increase in milk somatic cell count (SCC) in separate udder quarters. During a period of 13 weeks, 4158 bulk quarter milk samples from 68 cows were collected and analysed for milk SCC and milk composition. The sampling was done twice weekly. The cows were in different stages of lactation and in different lactation numbers. For calculations, three groups of cows were formed according to their SCC value. Group I cows, where all quarters had an SCC < 100 000 cells/ml at all sampling occasions, were considered to be non-affected. Group 2 cows had one udder quarter with an increased SCC > 100 000 cells/ml and 1.5-fold higher than the opposite quarter at one sampling occasion. For group 3 cows, the increase in SCC remained for several consecutive sampling occasions. Data from group I cows revealed that front and rear quarters were similar when compared with each other. For group 3 cows, the lactose content in milk decreased significantly, simultaneously with the increase in SCC and remained decreased for two sampling occasions after the initial increase in SCC. It was concluded that deviations in lactose content within front and rear quarters, respectively, may be a useful tool for detection of moderately increased SCC in separate udder quarters.