Can infectious omphalitis in piglets be clinically diagnosed during the first three days of life?

Abstract Background Globally, the increase in antimicrobial resistance is of great concern. In Denmark, the pig sector is accountable for the majority of antimicrobial usage in animals. As new-born piglets are at risk of developing infectious omphalitis, and many pigs are treated by antimicrobials within the first days of life, an early and accurate diagnosis of the disease is imperative to maintain animal welfare and reduce the antimicrobial usage. The aim of the present study was to compare histopathological and microbiological findings in piglets clinically diagnosed with and without omphalitis during the first three days after birth. Results A total of 98 case piglets with omphalitis and 98 control piglets without omphalitis, based on clinical examinations during the first three days of life, were included. Of the 196 piglets, 79 (38 cases and 41 controls) presented histopathological omphalitis. Post mortem, the volume of the umbilicus was significantly enlarged in cases compared to controls (p = 0.01). Except for a group of bacteria unidentified by matrix-assisted laser desorption ionisation time-of-flight (MALDI-TOF) (p = 0.02), no apparent association was found between histopathologically diagnosed omphalitis and the prevalence of specific pathogens (p > 0.05). The frequency of histopathologically diagnosed omphalitis tended to increase with increasing age in both cases and controls. The frequency of piglets with both histopathological omphalitis and arthritis/synovitis was significantly different among cases and controls (p = 0.05). This was due to all controls, and none of the cases, with arthritis/synovitis presented histopathological omphalitis. Conclusion The clinical differentiation between omphalitis cases and controls did not correspond to the histological diagnosis of omphalitis in zero-to-three days old piglets. An inaccurate clinical diagnosis complicates prudent use of antimicrobials in pig herds. In addition, animal welfare may be hampered in infected piglets due to lack of treatment and in healthy piglets due to the antimicrobial effect on the gut microbiome.