A field study of the associations between behaviors and reproductive performance in lactating sows

The present study examined factors associated with suckling, eating and postural behaviors (standing, lying and sitting) and the relationships between sow behaviors and reproductive performance. A commercial farrowing-to-finish farm with approximately 300 female pigs was visited eight times for 3 years to record sow behaviors using time-lapse video recorders for 24 hr. The lactational and postweaning reproductive performances of each sow were recorded using a recording software system. Statistical models were built to investigate the factors associated with each behavior. Regression analyses were performed to determine the associations between behavior measurements and adjusted 21-day litter weights (A21d-Wt), weaning-to-first-mating intervals (WMI) and occurrence of >or= 2 dead piglets during lactation. The means of suckling intervals and frequency of postural changes of the 145 recorded sows were 47.5 +/- 0.59 min and 86.8 +/- 2.97, respectively. As parity increased from 1 to >or= 4, the suckling interval and total standing duration increased (P<0.05). The number of nursing piglets and observation days 4 to 21 of lactation were not associated with the suckling intervals. A longer duration of lactation was associated with a longer total standing duration and a higher frequency of postural changes (P<0.05). Shorter suckling intervals were associated with heavier A21d-Wt (P<0.05). Each change in postural behavior increased the likelihood of occurrence of >or= 2 dead piglets during lactation (P<0.05). No postural or suckling behaviors were associated with WMI. Eating behavior was not associated with any reproductive performance. In conclusion, sow behaviors during lactation were related to lactational performance but were not related to postweaning reproductive performance.