The process of weaning in pigs: when the sow decides

Abstract

The aim of this experiment was to study the process of weaning in pigs and the effect of parity and litter size on this process. Behaviour was observed and weight gain and feed intake were recorded every week until 10 weeks postpartum for 22 litters and their dams in a special pen unit designed so that the sow could leave the piglets. The body weight of the piglets increased gradually to 29.89 kg at 10 weeks, and the intake of dry feed was low until Week 5, after which it increased rapidly. The time the sows spent with the piglets decreased gradually from 791±303 min per 24-h period at Week 2 to 142±265 min per 24-h period at Week 10. The number of sucklings per 24-h period decreased from 22.9±5.2 to 4.3±5.2, respectively. Half the sows weaned their young before 10 weeks. The sows increased their time away from the piglets during the day, but still preferred to stay with the piglets during the night. At 2 weeks the piglets initiated the majority (nearly 80%) of the sucklings and this increased to over 90% at 10 weeks. The proportion of initiated sucklings where the piglets were lying together with the sow decreased, and the proportion where sows were standing during suckling increased. The proportion of sucklings terminated by the sows increased from 50% at 2 weeks to nearly 90% at 10 weeks. The way in which suckling was initiated and terminated also varied over the 24-h period. Parity did not seem to affect the weaning process, but small litters were weaned later and had a higher body weight at 10 weeks.