The time required for changeover from colostrum to normal milk secretion varies with each species.

In cattle, Colostral milk tends to be stringy and yellow for several days postpartum. The complex bovine udder needs time for all areas to be flushed of colostrum. The milk of cattle is withheld from the milk supply for several days because of its unacceptable aesthetic quality, not because of the basic quality of the milk.