1. Effects on productivity and skeletal mineralization of high as opposed to moderate levels of protein and, or, energy intake by the ewe during pregnancy and lactation in the presence of adequate calcium, phosphorus and vitamin D have been studied.
2. Two experiments were undertaken. One experiment used 4½-year-old Cheviot ewes and the other used 3½- and 4½-year-old Scottish Blackface ewes. Weight records, blood samples and in vivo and flesh-free radiographs were obtained, and bone ash determinations were carried out.
3. The results showed that contrary to indications from earlier experiments in this series superiority in ewe weight, lamb growth, and mineralization of the ewe skeleton did not necessarily result from raising the protein and, or, energy values of the feed above the ‘moderate’ level.
4. Discrepancies between the in vivo and flesh - free radiological assessments were noted for consideration.