Tracking behavioral changes of confined sows from the first mating to the third parity.

The occurrence pattern of stereotypic behavior in high-parity confined sows is still unclear. We continually observed the behavioral changes in activity-restricted sows from the first mating to the end of the third parity. The results showed that the second- or third-parity weaned sows exhibited more vacuum chewing and total oral behavior than the first-parity sows. The vacuum chewing of sows in the second and third pregnancies was significantly more than that of the first-pregnancy sows at each stage of pregnancy, and the total oral behavior changed similarly. The sitting of sows in the second and third pregnancies was significantly more than that of the first-pregnancy sows in the early stage of pregnancy, whereas sitting behavior in the third pregnancy was significantly more than that in the middle stages of the first and second pregnancies. Vacuum chewing or sitting was positively correlated with confinement duration. In summary, vacuum chewing and sitting behaviors in sows confined from the first mating were significantly affected by parity. From the late stage of the first pregnancy to the middle stage of the second pregnancy is the key period of stereotypic behavior development for low-parity sows.