Whole wheat grain feeding of pregnant and lactating ewes and their lambs. 1. The influence of energy, sodium chloride and elemental sulphur on ewe productivity

Abstract

This experiment was designed to explore the influence of energy, sodium chloride and elemental sulphur on the productivity of pregnant and lactating ewes fed whole wheat grain diets. A central composite design was used to study the response over five levels of each factor. During the last 42 days of pregnancy, the energy treatments resulted in either maintenance of maternal body weights at about 42 kg, or losses of up to 5.5 kg. Ewe maintenance requirements were about 0.14 MJ ME kg-1 day -1 and their foetal requirement was 1 .I 5 MJ ME kg-1 day-1. Sodium chloride and elemental sulphur supplements had no influence on ewe liveweight change up to lambing, but wool growth increased with sulphur supplements of up to about 0.25 to 0.30 per cent. Energy intake and sodium chloride supplementation increased lamb birth weight. After lambing, ewes that had been offered low energy diets increased their liveweight gain and wheat intake with sulphur supplements whereas these supplements reduced the liveweight gain and wheat intake of ewes offered higher energy. Milk production measured on day 14 of lactation averaged 11 53 g day -1 and was not significantly influenced by treatment. These results are discussed in relation to the metabolism of pregnant and lactating ewes, and in the context of the composite design used.