PSIII-3 - Changes in Sow Posture from Weaning to Estrus

Abstract: Sows exhibit changes in behavior as they approach estrus that could aid in identifying the optimum time for insemination. The objective was to monitor changes in posture of sows from weaning to the first day that sows exhibited standing reflex. A cross-sectional survey was carried out using 99 multi-parous sows (in 7 groups) that were monitored over an 11–d period following weaning. At weaning, sows were moved from a farrowing to a breeding facility and were housed in individual stalls. Sows were checked daily for standing reflex from d 4 to 8 post-weaning; 97 sows exhibited standing reflex (80.4% of sows by d 6). Continuous video recordings were collected throughout the study period. Scan sampling was carried out on the videos every 5 min with the posture of each sow recorded (lying, standing, or sitting). The relative frequency of each posture was estimated as a percentage of the total number of observations within each day. Regression analyses were carried out using PROC REG of SAS to determine the rate of change in the frequency of active behavior (standing + sitting) from day of weaning to the first day of standing reflex. Over the study period, the frequency of sows lying, standing, and sitting was 76.5%, 20.0%, and 3.5%, respectively. The frequency of active behaviors increased linearly (P < 0.05) from day of weaning to day of standing reflex (Table 1); slopes ranged from 1.73 to 4.39 %/d depending on the period analyzed. However, there was considerable variation between sows with nine showing no change in the frequency of active behavior between weaning and standing estrus. These results suggest that changes in posture could potentially be used as a predictor for the start of estrus, however, further research is needed to understand individual sow variations in these postures.