Twenty synchronized Sakiz ewes aged 3-4 years were used in the study. Blood samples were taken once in pre-pregnancy and at the 100th day of pregnancy. At the 120th day of pregnancy and on the 10th day of lactation, blood samples were collected every 2 h for 24 h from only 10 ewes. Plasma cortisol levels were analyzed by radioimmunoassay. Plasma glucose and 3-hydroxybutyrate levels were determined spectrophotometrically. Plasma cortisol level slightly increased at the 100th day of pregnancy, decreased during late pregnancy and continued to decrease during lactation. Plasma glucose and 3-hydroxybutyrate levels were not significantly different during pre-pregnancy, pregnancy and the early lactation periods. In conclusion, the results showed that metabolic disorders such as pregnancy toxaemia did not occur in ewes fed a balanced ration sufficient in energy and protein levels even in a multiple lambing breed of ewes. Copyright (C) 2002 S. Karger AG, Basel.