PS6-5. Early Farrowing Pace and Parturition Outcomes

The objective of this study was to investigate the impact of initial farrowing pace on subsequent farrowing duration and the percentage of stillborn piglets. Sows (PIC, n = 315) on a 3,600-sow commercial farm were observed. Sow body condition was quantified using the Knauer sow caliper. Sows that had not farrowed by day 114 of gestation were induced. Farrowing duration, defined as the time interval between the birth of the first piglet and the last live-born piglet, was recorded for a subset of sows (n = 222). Initial farrowing pace was categorized by the number of piglets born in the first hour: 1 or 2 piglets (SLOW_START), 3 to 6 piglets (NORMAL), or greater than 6 piglets (FAST_START). Farm staff assisted 52% of sows during farrowing at their discretion. Farrowing duration ranged from 57 to 985 minutes, with an average of 241 minutes. SLOW_START, NORMAL, and FAST_START groups comprised 21.0%, 41.5%, and 37.5% of the sows, respectively. Farrowing assistance rates differed (P < 0.05) among the groups (SLOW_START, 57%; NORMAL, 61%; and FAST_START, 39%). However, farrowing pace was not associated (P > 0.05) with sow parity or sow caliper score. FAST_START sows had a greater (P < 0.05) total number born (16.8) compared to NORMAL (15.2) or SLOW_START (14.0) sows. Farrowing duration also differed (P < 0.05) by farrowing pace. The average farrowing durations for SLOW_START, NORMAL, and FAST_START were 342 minutes (range 174 to 985), 260 minutes (range 75 to 972), and 168 minutes (range 57 to 350), respectively. The percentage of stillborn piglets tended (P = 0.10) to differ across the pace groups, with percentages of 6.8%, 4.8%, and 4.4% for SLOW_START, NORMAL, and FAST_START, respectively. Furthermore, farrowing duration was positively correlated (P < 0.05) with the percentage of stillborn piglets (r = 0.17). Sows receiving farrowing assistance had similar (P > 0.05) farrowing durations (248 vs. 233 minutes) and comparable percentages of stillborn piglets (5.2% vs. 5.2%) to unassisted sows. Results indicate that sows with a FAST_START required less farrowing assistance and gave birth to larger litters compared to NORMAL or SLOW_START sows. While early farrowing pace was a strong predictor of farrowing duration, it was not a significant predictor of stillborn piglet percentage in this study.