Mortality attributed to respiratory problems among finisher pigs in the United States.

In the 1995 National Swine Study of the United States National Animal Health Monitoring System, producers identified respiratory problems as the leading cause of death in pigs during the grower/finisher phase of production. Over a six-month period, 61.7 +/- 4.1% (mean +/- SEM) of operations reported at least one death attributed to respiratory problems among finisher pigs (based on 388 operations representing operations with > or = 300 finisher pigs in 16 states). Mean mortality attributed to respiratory problems was 0.9 +/- 0.1% of finisher pigs per operation. Stepwise logistic regression (using SAS) was used to identify factors associated with operations attributing at least one death to respiratory problems, and to identify factors associated with reporting > or = 2% mortality attributed to respiratory problems. Final models were run with SUDAAN to account for the sampling strategy. Attributing at least one death to respiratory problems was associated with having > or = 3000 pigs enter the grower/finisher unit over a six-month period; diagnosis of Haemophilus (or Actinobacillus) in the past 12 months; and keeping pigs in the grower/finisher unit > 120 days (as compared to < 100 days). Not having a farrowing facility, mean weaning age < 28 days, and < 50% of finisher pigs on solid concrete only were associated with reporting > or = 2% mortality attributed to respiratory problems.