Twenty synchronized Sakiz ewes (aged 3-4 years) were used in this study. Blood samples were taken once in pre-pregnancy and at the 100th day of pregnancy. At the 120th day of pregnancy and the 10th day postpartum, blood samples were collected every 2 h for 24 h from 10 ewes. Plasma progesterone and estradiol-17beta levels were estimated by radioimmunoassay. Plasma cholesterol levels were determined by colorimetric method. Plasma progesterone levels increased during pregnancy and especially late pregnancy and decreased to basal values during lactation. Plasma estradiol-17beta and cholesterol levels were not significantly different between pre-pregnancy, pregnancy and early lactation periods. The insignificant rise in plasma cholesterol during pregnancy showed that pregnancy toxemia may not occur in multi-pie lambing ewes when fed a balanced diet sufficient in energy and protein levels. The increased plasma progesterone level above normal observed during pregnancy and especially late pregnancy may be interpreted as a feature of multiple lambing breeds. Copyright (C) 2003 S. Karger AG, Basel.