Progressing alteration of parathyroid function in cattle from experimental high and low calcium feeding.

Changes in function of the parathyroid gland was studied periodically for 36 days in two groups of calves fed high and low calcium diets. After changes to the experimental diets, parathyroid function was altered in some calves at 9 days of high or low calcium feeding. Parathyroid function was reduced in high calcium feeding and increased in low calcium feeding. These changes increased progressively in intensity with the lapse of time during experimental feeding periods.