The challenge of large litters on the immune system of the sow and the piglets

The use of hyperprolific sow lines has increased litter size considerably in the last three decades. Nowadays, in some countries litters can reach up to 18-20 piglets being a major challenge for the sow's physiology during pregnancy, parturition and lactation. The increased number of piglets born per litter prolongs sensibly the duration of farrowing, decreases the piglets' average weight at birth and their vitality, increases the competition for colostrum intake and can affect negatively piglets' survival. This review aims to describe how large litters can affect the immune system of the sow and the piglets and proposes measures to improve this condition.Peer reviewe

The effect of farrowing duration on maternal behavior of hyperprolific sows in organic outdoor production

Prolonged farrowing duration has previously been related to hypoxia, stillbirth and poor sow health post partum (pp). A difficult farrowing may affect sow behavior through exhaustion, sickness or pain and thus constitute a risk for sub-optimal maternal behavior. The aim of the present work was to study if the duration of farrowing in an organic sow herd affected sow postural changes, carefulness of lying down and nursing behavior relevant for early piglet mortality. Thirty-eight sows and their piglets housed in individual paddocks with an A-frame hut were video recorded from the day of farrowing and the following 72 h. The average farrowing duration till the last live born piglet was 7.5 ± 7 h (2.1–28.9 h). The only effect found of farrowing duration was a 22 ± 10 min reduced latency to leave the hut after birth of the last live born piglet when the farrowing increased with one hour. Other results showed normal, passive sow behavior with increasing activity as days past post partum (pp). Despite a large range in farrowing durations, no considerable effects were found suggesting exhaustion affecting maternal behavior. The results suggest that these organic sows were resilient enough to get through even a difficult farrowing without being energy depleted