NURSING AND SUCKLING BEHAVIOR OF SEMI-NATURALLY KEPT PIGS DURING THE 1ST 10 DAYS POSTPARTUM

Two groups of Swedish Landrace pigs were kept in semi-natural enclosures of 7 and 13 ha. Out of these groups, the nursing and suckling behaviour of seven multiparous and three primiparous sows and their litters were studied during two 2 h sampling sessions per day during 10 days postpartum in the period June-August 1987. The suckling frequency slowly increased from about 0.9 to 1.4 h. During the first days, the sows initiated and the piglets terminated 80-100% of the sucklings; at the end of the period the figures were 40-55%, indicating that the piglets were more active and the sows possibly less inclined to nurse. During the first days, the piglets were less synchronized in their suckling behaviour, indicated by a smaller proportion of piglets taking part in the sucklings (on average about 85% of the litter on Day 1, as compared to 95-100% on the third day onwards). This was probably reflected in the pre-massage time (the massage needed to induce a milk ejection), which was longer at the beginning of the period (on average about 150-160 s during the first 2 days and about 110 s and less from Day 3 onwards). Udder massage was also performed at an increasing rate outside sucklings. The frequency of piglet-initiated nose contacts after milk ejection increased during the period, while the frequency before sucklings decreased. The findings were interpreted so that some aspects involved in the weaning process, defined according to an hypothesis suggested earlier, have already started during the first days postpartum, even if that does not mean that weaning actually started immediately after birth.