PSIV-15 - Impact of Wean Age and SID Lysine Level on Performance in Lactation

Abstract: With genetic improvement, sows are having larger litters and nursing more pigs. The wean age of these piglets can impact sow feed intake and piglet wean weight. Additionally, Lys level can impact sow and piglet growth. This study was performed to assess whether the addition of higher standardized ileal digestible (SID) Lys improves sow and litter performance for two wean ages. Four hundred thirty-two DNA F1 females (average parity 2.4) were randomly allotted within group and entry weight at farrowing to one of four dietary treatments. Treatments were arranged in a 2 x 4 factorial with wean age (15.5 and 24.5 d) and lactation diet SID Lys (0.87, 0.94, 1.02 and 1.10%). Sows were weighed entering and exiting the farrowing room. Feed disappearance was calculated as the total amount of feed provided to the sow during lactation. A post-farrow weight model was utilized to assess true weight loss in lactation. Litters were standardized within 24 h of birth. Data were analyzed as a randomized complete block design with fixed effects of SID Lys and wean age, and random effect of replicate. Average daily feed intake was increased (P < 0.05) in the sows weaning older age compared to younger age piglets (6.52 vs. 5.87 kg respectively). There was a tendency (P < 0.10) for an interaction between wean age and maternal Lys level on piglet wean weight as higher Lys increased wean weight (0.29 kg) in the older wean age but had no improvement in the younger wean age. Sow weight loss was decreased (P < 0.05) in sows weaning younger piglets compared to sows weaning older piglets (4.26 vs. 11.02 kg weight loss, respectively). These data show that higher levels of SID Lys to target 65 g/d in lactation can improve wean weight for later weaning sows.