Comparative productivity and health status of S.E.W. nursery pigs fed different types of dietary antimicrobials

摘要

The health status and environment of pigs influences their productivity which can be modified by disease control effects of dietary antimicrobials. A major part of this disease control effect has been shown to be mediated in part by the level of immune system activation (i.e. health status) of pigs which can also be influenced by dietary antimicrobials. The response to dietary antimicrobials is greater when control (untreated) animals grow more slowly than normal, which may also be a reflection ofhealth status. Our studies support the concept that the productivity response of pigs to dietary antimicrobials is mediated in part by their relative ability to improve the health status of pigs, even in high health status herds. All five trials reportedhere were conducted in the first two weeks post-weaning. In trial 1, conventionally weaned pigs weighing an average of 13.8 pounds were obtained from a single source and placed on a standard nursery diet in a research facility Mild post-weaning diarrheaoccurred naturally, without any death loss or requiring supplemental treatment. The only treatment group to have a significant reduction in diarrhea and significant improvements in feed intake and rate and efficiency of growth was the one receiving thecombination of tiamulin/chlortetracycline (ctc), both of which have broad spectrum activity and systemic (both respiratory and enteric) drug distribution. This activity resulted in significant performance improvements compared to other antimicrobials which are more limited in both distribution and activity.