Transfer of maternal calcium to the offspring via the milk.

By measuring the specific activities of milk and of maternal and filial long bones 3 months after calcium-45 had been given to the then nonpregnant mothers, it was found that the magnitude of the contribution of the maternal calcium stores to milk formation is similar to the contribution to the bone calcium of the offspring, that is, 10 to 15 percent of either milk calcium or filial calcium is maternal in origin.