Effects of dietary deficiencies of energy, protein and calcium on the pregnant ewe. III. Some observations on the use of biochemical parameters in controlling energy undernutrition during pregnancy and on the efficiency of utilization of energy and protein for foetal growth

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Abstract
SUMMARY Twenty-eight 6½-year-old Scottish Blackface ewes were used in a 2 × 2 factorial experiment and given semi-purified diets containing 11·8 or 6·0% crude protein (CP) and 1·2 or 0·11 % calcium (Ca) in the dry matter (DM). The amounts of diet offered were adjusted to maintain non-esterified fatty acids (NEFA) and ketone bodies in the plasma at levels comparable to those found in hill sheep in winter. Mean group values of NEFA during the final 6 weeks of pregnancy were maintained at these levels (1100–1300 μ-equiv/1) and ketone bodies at approximately 4·8 mg/100 ml. A further six sheep were fed a conventional diet containing adequate CP and Ca, to maintain NEFA and ketone bodies at levels typical of well-nourished sheep. Ewes and lambs from the undernourished groups were slaughtered after parturition and the chemical compositions of their bodies and those of six ewes slaughtered at the commencement of the experiment determined.