242. Behavioral and Physiological Indicators of Litter Outcome in Gestating Gilts.

Abstract With rapid development and integration of precision technologies on swine farms, research is needed to identify behavioral indicators of productivity to inform these technologies and translate data into management recommendations. Biological relevance of postural behaviors that are common in automated identification and tracking is largely unknown. The objective of this study was to investigate salivary biomarkers and postural behavior in gestating gilts as potential indicators of farrowing outcomes. To achieve this, 16 gilts were housed in 4 pens of free-access stalls (n = 4/pen). Gilts were unlocked from the stalls, initiating social mixing, at 30 days of gestation (dg) and maintained as stable groups for the remaining gestational period. Saliva was collected by allowing the gilts to passively chew on ropes at 30 and 90 dg. Overhead, continuous video was recorded from 12:00 – 20:00 h at 30 and 90 dg. Recorded video was manually decoded for gilt location (pen, stall) and posture using instantaneous scans at 1 min intervals for a total of 480 scans per timepoint and 960 scans overall. Salivary cortisol, testosterone, and progesterone were quantified using commercially available ELISA kits. Farrowing outcomes recorded for each litter included total number born (TNB), number born alive (NBA), stillbirths, mummies, overlays, litter birth weight (LBW), average birth weight, birth weight standard deviation as a measure of piglet uniformity, number weaned, and litter wean weight (LWW). Greater kneeling behavior at 30 dg was significantly correlated with incidence of farrowing mummies (R = 0.75, P = 0.008, FDR = 0.012). At 90 dg, kneeling behavior was positively correlated with overlaying (R = 0.70, P = 0.005, FDR = 0.069). Sitting behavior at 90 dg was positively correlated with farrowing mummies and negatively correlated with number weaned (R = 0.74, P = 0.002, FDR = 0.042; R = -0.77, P = 0.001, FDR = 0.030, respectively). Each of these relationships remained significant after correcting for TNB. Gilts that spent more time lying sternal as opposed to lateral at 30 dg had less uniform piglets (R = 0.70, P = 0.008, FDR = 0.069). Similarly, sternal lying at 90 dg was negatively correlated with number weaned and LWW (R = -0.74, P = 0.002, FDR = 0.042; R = -0.72, P = 0.004, FDR = 0.063, respectively). There were no correlations detected between postural behaviors and salivary biomarkers, or between salivary biomarkers and farrowing outcomes. Nonetheless, these data suggest that kneeling and sitting behavior in gestating gilts are promising behavioral indicators of at-risk litters, and excessive sternal lying may be indicative of gilts that will be poor producers. As technology is already able to detect and differentiate between postural behaviors, this data provides insights for development of future precision tools for management and gilt selection.