Development and characterisation of a model of bovine inflammation

Two dialysis sacs each containing 50 ml dextran sulphate solution were implanted into the peritoneal cavities of five three month-old calves. One sac was inoculated with Pasteurella haemolytica or Streptococcus uberis and the second sac served as an uninoculated control. Samples of sac fluid removed after 0, four, six, eight, 15, 24, 36 and 48 hours and then at 24 hour intervals after inoculation revealed bacterial growth up to 9.0 log10 cfu ml-1 by two to three days after inoculation. Concentrations of 25 to 48 ng ml-1 of the inflammatory mediator prostaglandin E2 (PGE2) were detected six to 96 hours after inoculation, similar amounts being generated in sacs inoculated with either bacterium, but the concentrations in control sacs remained below 10 ng ml-4 over the seven day experiment. Post mortem, a tissue cast invested each of the inoculated sacs. Histologically, the reaction was an acute inflammatory response similar to that evoked by each bacterium in the target organ.