Increased dietary protein for lactating sows affects body composition, blood metabolites and milk production

Hyper-prolific sows nurse more piglets than less productive sows, putting a high demand on the nutrient supply for milk production. In addition, the high production level can increase mobilization from body tissues. The effect of increased dietary protein (104, 113, 121, 129, 139 and 150 g standardized ileal digestible ( SID ) CP/kg) on sow body composition, milk production and plasma metabolite concentrations was investigated from litter standardization (day 2) until weaning (day 24). Sow body composition was determined using the deuterium oxide dilution technique on days 3 and 24 postpartum . Blood samples were collected weekly, and milk samples were obtained on days 3, 10 and 17 of lactation. Litter average daily gain ( ADG ) peaked at 135 g SID CP/kg ( P P P P P P P P =0.41). In early lactation (day 3 + day 10), plasma urea N ( PUN ) increased linearly after the breakpoint at 139 g SID CP/kg at a concentration of 3.8 mmol/l, and in late lactation (day 17 + day 24), PUN increased linearly after a breakpoint at 133 g SID CP/kg ( P