Mortality on grower/finisher-only swine operations in the United States

For 53 grower/finisher-only swine operations that participated in the United States National Animal Health Monitoring System 1995 National Swine Study, mortality among finisher pigs ranged from 0 to 12.0% over a 6-month period. Twenty-six (49.1%) had <2% mortality, and 27 (50.9%) had >2% mortality. Nine (17.0%) operations experienced >4% mortality. Fisher's exact test revealed that operations with all-in all-out management were significantly more likely to have <2% mortality than operations with continuous management, and that operations where all finisher pigs came from farrowing units belonging to the operation (either on-site or off-site) were significantly more likely to have <2% mortality than operations where >1 grower/finisher pig came from another source. Larger operations (where >900 pigs entered the grower/finisher phase) practiced all-in, all-out management more frequently than smaller operations, and had a lower mean percent mortality than smaller operations. Diagnosis of Salmonella in finisher pigs performed at a laboratory or by a veterinarian in the 12 months prior to interview was associated with both increased percent mortality and increased percent mortality per day.