Wheat, J.D.Allee, G.L.Hines, Robert H.2010-04-302010-04-302010-04-30http://hdl.handle.net/2097/3831Based on the first 76 farrowings recorded, average duration (the time between the birth of the first pig and of the last pig in the litter) was 129.09±7.28 minutes, and the average time interval between pigs was 15.71± 1.02 minutes. Longer farrowings were associated with longer intervals (r=.73), but farrowing duration and litter size at birth were not closely related (r=.19, P>.05). Farrowing duration was positively associated with the number of pigs born alive (r=.34, P<.0l). Farrowing interval, a better criterion of speed of farrowing than farrowing duration, was significantly associated with number of pigs alive at birth and at weaning; the correlations were, respectively, -.75 and -.78. Farrowing interval was also negatively associated with litter weight at 21 days, the correlation was -.32 (P<.05). So naturally it was negatively associated with the National Swine Improvement Federation's sow-productivity index: (r=-18, P<.05). The index is 6.5 times the number of pigs born alive plus litter weight of pigs 21 days old. The number of live pigs per litter at birth averaged 9.75±.34 and at 21 days, 8.60±1.2.SwineFarrowingPig performanceConference paper