Milk yield and quality at cow udder quarter level as influenced by quarter position, pathogen and somatic cell score

Few information on milk from complete draining of individual udder quarters is currently available. The aim of the study was to assess how and to which extent milk yield and quality at udder quarter level are influenced by quarter position, pathogen and somatic cells. Quarter milk samples (n=120) of 10 Simmental cows were collected in three consecutive sampling days. Milks were analysed for bacteriology, chemical composition (fat, protein, casein and lactose, %), pH and urea content (mg/dL). Somatic cell count (SCC) and differential SCC were also determined. Data were analysed with a linear mixed model which included the fixed effects of quarter position (right front, left front, right rear, left rear), pathogens (presence or absence) and somatic cell score (SCS) (4 classes, defined on quartiles of SCS distribution), and the random effects of cow nested within quarter level and residual. Quarter position significantly affected milk yield (p < 0.05), with rear quarters being the most productive. Pathogens had a negligible effect on milk yield and quality. Somatic cell score was significant in explaining the variability of fat, lactose, DSCC and pH (p < 0.05).