Natural variations in the average size of bovine casein micelles: I. Milks from individual Ayrshire cows

Summary Milk samples from 3 groups of cows were taken at regular intervals throughout lactations following 2 spring and 1 autumn calving. The average radius of casein micelles in milk was determined either from the wavelength dependence of turbidity or from the diffusion coefficient as measured by a quasi-elastic light scattering method. A 2-fold variation in naturally occurring average radii was found both in milks from the same cow at different times and between milks from different cows at the same time.