273 Impact of either high energy or high SID Lys:ME on Parity 1 performance in lactation

Primiparous sows may have difficulty consuming sufficient feed during lactation to account for energy lost in milk production, development, and body maintenance. Addition of higher energy and/or higher standardized ileal digestible (SID) Lys may improve gilt and litter performance. One hundred seventy-two primiparous DNA F1 females were randomly allotted within breeding/farrowing group, previous treatment, and entry weight at farrowing to one of four dietary treatments. Treatments were arranged in a 2 x 2 factorial with energy (3186 and 3332 kcal/kg ME) and SID lysine (1.15 and 1.30%). Sows were weighed upon entry and exit of 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, and individual pig birth and weaning weights were recorded. The wean to estrus interval was also measured. Data were analyzed as a randomized complete block design with the fixed effect of treatment and the random effect of replicate. Addition of high energy and/or high lysine did not impact (P > 0.10) piglet wean weight or sow average daily feed intake. High energy diets reduced (P < 0.05) sow weight loss post-farrow by 15.5% from 8.75 to 7.39 kg. High SID lysine diets reduced (P < 0.05) number of sows not expressing estrus by day 9 post-wean from 13.0 to 7.7% of sows eligible for insemination. The high SID lysine diets targeted 70 g/d and led to an increase (P < 0.05) of 10.3% of sows displaying estrus on day 4 and 5. These data show that higher levels of SID lysine to target 70 g/d in lactation can improve wean to estrus interval, and potentially decrease non-productive sow days.