A retrospective study of mortality in grow-finish pigs in a multi-site production system

Objectives: To investigate overall and weekly mortality in grow-finish pigs in a large multi-site production system, and to assess the associated financial losses. Materials and methods: Between January 1996 and January 2000, mortality was investigated retrospectively in 14 swine complexes, including 146 closeouts comprising 1,345,127 pigs. Overall mortality during the entire grow-finish period was expressed as deaths per 1000 pig weeks. Weekly mortality was the number of pigs that died during a week divided by the average inventory of pigs during that week. Opportunity costs of mortality were assessed for each year of the study. Results: Mean overall mortality during the 4 years was 3.23 per 1000 pig weeks. Mortality increased steadily from 2.6 (1996) to 3.6 per 1000 pig weeks (1999) (P<.001). Late mortality was consistently greater than early mortality (P<.001), and increased from 3.1 (1996) to 5.5 pigs per 1000 pig weeks (1999) (P<.001). Opportunity costs due to overall mortality increased from $2.86 per marketed pig in 1996 to æ5.22 in 1999, with late mortality, which was more pronounced during fall months, accounting for about two thirds of these total costs (SUS). Implications: Increased mortality rates occur mainly in older, more valuable finishing pigs and cannot be predicted by early mortality. Mortality records should be analyzed to investigate patterns. Weekly mortality rates may be calculated using the record keeping systems used in many US swine farms. Causes of death and risk factors for the seasonal change in mortality pattern warrant further research.