LAUSR

Genetic selection for hyper-prolificacy in sows has resulted in a significant increase in the number of piglets born alive per litter; however, a consequence has been a reduction in piglet vitality and survival. Increasing lactation dietary energy density can increase sow energy intake and the survival and growth of piglets from large litters. The objective of this experiment was to investigate the effect of increasing sow lactation dietary energy density on piglet vitality and growth to weaning. At d 108 of gestation, sows (n = 115) were blocked by parity, BW and backfat, and randomly assigned to one of four energy density diets until weaning; 13.8, 14.5, 15.2 and 15.9 MJ DE/kg. At birth, body temperature, IUGR traits and muscle tone were recorded in piglets. At 24 h, piglet body temperature and blood glucose concentration were recorded. Piglets were weighed throughout lactation. Data were analysed using the mixed models procedure in SAS (v.9.4). Average daily energy intake was highest for sows fed 15.9 MJ DE/kg compared to sows fed 13.8, 14.5 and 15.2 MJ DE/kg (115.1 v 98.92, 102.33, 107.83MJ DE/d±1.51; P < 0.01). Piglets from sows fed 13.8 and 15.9 MJ DE/kg were more likely to have more IUGR traits and a higher muscle tone score, respectively, compared with all other treatments (P < 0.01). The 24 h body temperature was higher for piglets from sows fed 13.8 and 15.2 MJ DE/kg than piglets from sows fed 15.9 MJ DE/kg (35.47 and 35.48 v 35.22⁰C±0.05; P < 0.01). Glucose concentration was higher for piglets from sows fed 14.5 MJ DE/kg than piglets from sows fed 15.9 MJ DE/kg (4.70 v 4.15mg/ml±0.14; P < 0.01). Litter weaning weight was heaviest for sows fed 13.8 MJ DE/kg compared with sows fed 14.5 MJ DE/kg (92.90 v 84.97kg±1.59; P < 0.01). In conclusion, feeding lactating sows 15.9 MJ DE/kg increased daily sow energy intake and improved piglet development.