MATERNAL-BEHAVIOR OF LACTATING SOWS IN A LOOSE-HOUSING SYSTEM

The aim of this experiment was to investigate the process of weaning and the motivation of the sow to continue nursing in a system where the sow could leave the piglets and join other sows in a common area; and further to look at the effect of parity and number of piglets in the litter on the weaning process. The behaviour of 16 sows with litters was recorded every week from Week 2 to Week 10 postpartum. Body weight and feed intake of the piglets were also recorded on a weekly basis. In Week 2 the sow spent 775 min day-1 with the piglets (53.8% of the 24-h period), but in Week 4 it was as low as 28 min day-1 ( 1.9% of the 24-h period). The number of sucklings decreased similarly from 20.4 in Week 2 to 4.8 in Week 4, and nine out of 16 sows had virtually weaned their piglets before 5 weeks postpartum. The proportion of sucklings terminated by the sow had already reached 100% by Week 5. The early weaned litters had a poorer weight gain, and did not increase their intake of concentrates to compensate for the reduced milk transfer. These results suggest that in an integrated system where the sow can leave her piglets and have social interaction with other sows, the bond between mother and offspring is weakened so that weaning can occur very early.