Energy and protein nutrition of ewes in late pregnancy

Feeding of the pregnant ewe affects its weight and condition and subsequently the ability to supply the lambs with adequate nutrition. Supplementing is commonly used to secure adequate birth weight and growth rate but for efficient use the condition of the ewes as well as total composition of the diet has to be considered thoroughly. In the experiment described here the effect of feeding different concentrates during the last month prepartum on ewe and lambs health and performance were tested on 48 ewes and their progenies. Ewes were assigned to four treatments, each containing equal numbers of single- twin- and triplet bearing ewes. All lambs were reared as twins. Three of the treatment groups (MIX, EN and PRO) were fed, along with ad libitum haylage, increasing levels of supplements differing in protein type and content while the fourth group was control group (CTR) and only fed haylage. Ewes were weighed and scored for BCS before and after the experimental period, haylage intake recorded daily and blood samples collected weekly for metabolite analysis. Lambs were weighed at birth, seven days old, approximately seven weeks old and at last at weaning. Supplemented ewes ate significantly less haylage than CTR ewes. Though treatment did not affect weight, BCS nor weight and BCS changes, CTR ewes gained significantly less weight than the PRO ewes and the MIX group ewes had significantly higher BCS in April than other. Single bearing ewes gained less weight and were lighter at parturition than other while triplet bearing ewes had the lowest BCS and lost condition in all supplemented treatments. Treatment affected glucose, BHB, urea, uric acid, AST, ICDH and calcium level significantly, BHB and urea level increased with higher levels of undegradable protein. Glucose, urea, uric acid and ICDH levels were affected by litter size, single bearing ewes having the lowest levels of ICDH and uric acid but the highest levels of glucose and urea. No significant difference was found for birth weight between treatments. The first weeks postpartum lambs reared by CTR ewes had significantly lower growth rate than others but this difference ceased with increasing age. Type of supplements did not affect growth rate significantly and live weight at weaning did not differ significantly between treatments. Lambs reared by ewes that had given birth to twins had significantly higher growth rate the first week postpartum but the difference then ceased and was not found after seven weeks of age.