PSIII-3 Effect of Day of Induction on Sow and Piglet Performance

Induction can be a useful herd management tool. However, inducing too early can negatively impact critical biological processes for the sow and her piglets. Although inducing at 115 d of gestation is widely accepted for commercial sows, the natural gestation length of purebred lines can exceed 115 days. Therefore, the objective of this study was to estimate the effect of induction at 115 vs. 117 d of gestation on the performance of purebred sows and their piglets. Purebred Landrace females from a commercial multiplier were used for this study. Sows were mated to one of the following genetic lines: A, B, or C. Of the 601 sows placed on test, 264 and 135 sows farrowed as a result of induction at 115 or 117 days of gestation, respectively. From these 399 sows, piglets sired by line C (n=1,715) were used for subsequent analyses. Traits of the sow analyzed included: percent stillborn, sow mortality (from 0 to 24 days post-farrowing), and removal rate (between farrowing and weaning). Traits of the piglet analyzed included: weaning weight, lactation ADG, and pre-weaning mortality. All traits were analyzed using a generalized linear model, except for mortality and removal rate, which were analyzed using a LOGIT model. Piglets from the 117 group had significantly greater weaning weight (P=0.02), significantly greater ADG (P=0.0009), and numerically lower pre-weaning mortality (P=0.16) than piglets from the 115 group. Sows induced at 117 days of gestation had numerically lower percent stillborn, lower mortality, and lower removal rate than sows induced at 115 days of gestation, although not significant (P=0.13, P=0.48, and P=0.50, respectively). In conclusion, there was a numerically or significantly favorable effect of inducing sows at 117 vs. 115 d of gestation on both sow performance and early-life piglet performance.