Comparative biochemistry of ewe serum during oestrus and dioestrus.

Abstract

In oviparous and ovoviviparous animals, the oestrous period is accompanied by striking changes in composition of blood (Urist, Schjeide & McLean, 1958). Limited information is available, however, on changes in the composition of the blood of mammals during the reproductive cycle. The research reported in this paper concerns changes in blood plasma biochemistry during the oestrous and dioestrous phases of the cycle in the ewe. Six mature ewes which had shown two consecutive oestrous cycles of normal duration were bled from the jugular vein on the day of oestrus. The same six animals were bled 6 days later during dioestrus. For both phases, ewes were bled at 09.00 hours before daily feeding. The blood samples were spun at 1600 g for 10 min and the serum was frozen at