Mj. Auldist et al., CHANGES IN THE COMPOSITION OF MILK FROM HEALTHY AND MASTITIC DAIRY-COWS DURING THE LACTATION CYCLE, Australian journal of experimental agriculture, 35(4), 1995, pp. 427-436
Variations in milk composition during lactation were studied in normal
and mastitic dairy cows from 2 seasonally calving herds in northern V
ictoria. Milk yields, somatic cell counts (SCC), and concentrations of
lactose, fat, total protein (TP), casein protein (CP), non-casein pro
tein (NCP), sodium, potassium, and calcium varied considerably as lact
ation progressed. The basic patterns of change over lactation were sim
ilar whether cows were healthy or mastitic (SCC > 3 x 10(5) cells/mL m
ilk). Milk from mastitic cows had higher concentrations of TP, NCP, an
d sodium, but lower concentrations of fat, lactose, CP, and potassium,
than milk from healthy cows, although differences were not consistent
ly significant. The activity of the milk protease, plasmin, was positi
vely correlated with log(10)SCC in both herds.