The influence of energy intake on plasma levels of glucose, non-esterified fatty acids and acetone in the pregnant ewe

Abstract

SummaryForty cross-bred ewes were individually fed from the end of week 13 of pregnancy to parturition on two diets whioh were designed to provide intakes of metabolizable energy above (treatment El) and below (treatment E2) the maintenance requirement of the non-pregnant ewe.Energy intake had no significant influence on birth weight of single lambs but twin lambs from ewes on treatment E1 were 25% heavier than twins from ewes on treatment E2. A net loss of body weight occurred between week 13 of pregnancy and the day following parturition in all groups of ewes. These losses represented 5 and 10% of body weight in ewes carrying singles on treatments E1 and E2 respectively. In ewes carrying twin lambs losses represented 11 and 16% of body weight on treatments E1 and E2 respectively.Levels of plasma N.E.F.A. and acetone were used to characterize the state of nourishment of ewes at 16, 18 and 20 weeks pregnant. Values obtained indicated that ewes carrying one lamb on treatment El were ‘moderately’ undernourished. Ewes carrying one lamb on treatment E2 and those carrying twin lambs on treatment E1 were undernourished to a similar degree characterized as bordering between ‘moderate’ and ‘severe’. Ewes carrying twin lambs on treatment E2 and all those carrying triplets were ‘severely’ undernourished.