A prospective study of sow mortality in breeding herds.

This investigation was conducted to study the incidence and the causes of sow mortality in breeding herds. Data were obtained from 24 swine breeding herds with an average inventory of 3755 sows and served gilts for the total sample. Producers were involved for 12 consecutive months and agreed to submit to the diagnostic laboratory every dead or moribund sow and served gilt. The average herd death rate was 3.3% +/- 0.5 (SEM), but varied considerably among herds, ranging from 0% to 9.2%. A total of 137 sows and mated gilts died during the year, and these females had produced an average of 4.2 litters +/- 0.2 (SEM). The number of deaths was significantly higher during the months of July, August and October. The peripartum period appeared to be when sows were most at risk, with 42% of all deaths occurring during this short period of the reproductive cycle. The three major causes of death were heart failure (31.4%), torsions and accidents of abdominal organs (15.3%) and cystitis-pyelonephritis (8.0%). Other causes included endometritis (6.6%), uterine prolapses (6.6%), pneumonia (3.6%), gastric ulcers (3.6%), downer sow syndrome (2.2%), miscellaneous (8.0%) and unknown (14.6%).