An Evaluation of Performance of “Disease-Free” Pigs in Repopulated Farm Herds

Losses in livestock caused by diseases, parasites and insect pests in the United States have been estimated at more than two billion dollars a year. These losses have occurred in spite of man’s continual effort to control disease. In the past, methods of disease control such as immunization and the use of antibiotics have added materially to the control of disease and increased production. There are many diseases, however, for which vaccines are not available and which antibiotics do not control. A new approach to control infectious disease of swine was presented in 1955. Briefly, these methods are: 1) obtain aseptic pigs by hysterectomy, 2) raise pigs in isolation during early life, 3) use normally farrowed offspring to restock other farms. The object of this study was to determine and evaluate the performance of pigs obtained by the above described methods in repopulated farm herds. Seventy-one “disease-free” pigs were placed on four Nebraska farms during 1957-1959. The offspring from 26 females on two of these farms were used to repopulate 45 additional farms with 675 females. Records of performance were kept on all pigs on the first 11 farms in the repopulation program. Comparison of “disease-free” pigs with contaminated pigs from several other sources show superior performance of the “disease-free” pigs from three to 42% increase in total production. Advisor: L. J. Sumptio