The influence of dietary energy intake during successive lactations on sow prolificacy

From selection prior to the production of their first litters, 101 Yorkshire × Landrace sows were allocated to be ad libitum fed either a control (CE) or high energy diet (HE) during each of four successive lactations. Diets CE and HE supplied 13.7 and 15.6 MJ. DE kg−1, respectively. Sows were treated similarly during each gestation. Although HE sows tended to have a greater digestible energy intake, they lost more weight during each lactation (P < 0.05). Maternal weight gains between each farrowing decreased with successive parities (P < 0.05). Litter size at the second and subsequent farrowings was greater (P < 0.05) for the HE than CE sows. The overall mean litter size for the HE and CE sows was 10.1 and 9.3 piglets, respectively. A similar trend was noted for live births (9.7 vs. 8.9) and numbers weaned (8.3 vs. 7.9). There was no consistent effect of treatment on pig weights at birth or 21 d of lactation. No treatment or parity effects were evident for preweaning pig mortality. The weaning to concept...