Timing and causes of piglet mortality in alternative and conventional farrowing systems

The causes and timing of piglet mortality were studied in different farrowi ng systems. In the first experiment 198 litters were recorded in three syst ems, two of which allowed the sows to move freely, and the third restricted them in conventional crates. More piglets were weaned from the conventiona l crates than from the open systems and they grew more quickly. More than h alf the liveborn mortality occurred during the first four days after partur ition. In the open systems, 17 per cent and 14 per cent of the piglets born alive were crushed, compared with only 8 per cent in the crates. In the se cond experiment, 29 sows and litters were studied in detail in a communal p en system during the first seven days of lactation. Three-quarters of the l iveborn mortality was due to crushing. The total number of piglets dying pe r litter, including stillbirths, was significantly associated with the tota l litter size and the sow's parity. The percentage liveborn mortality was s ignificantly associated with the parity and body length of the sows and wit h the within-litter variation in the birth weight of the piglets. Individua l birth weight was closely associated with percentage survival. Only 28 per cent of piglets weighing less than 1.1 kg at birth survived to seven days.