“…Following thyroparathyroidectomy of lactating rats, it was shown that the litter weight was reduced and very little milk could be removed on day 14 of lactation (5). While the reduction in milk secretion may have been due, primarily, to the low serum calcium level due to parathyroidectomy, the rats at the end of the test milking showed the presence of considerable amounts of milk which was not removed by oxytocin during the 30 minute nursing procedure.…”