Post weaning diarrhoea syndrome (PWDS) in piglets is caused mainly by enterotoxigenic Escherichia (E.) coli (ETEC) strains. Six different in-feed usage programmes of enrofloxacin (ENR/Baytril(R); I.E.R. 2.5%) were rested for their efficacy on the control of post weaning colibacillosis in piglets, using seven groups with totally 336 weaned piglets for a 28 day period. One group (negative control) was offered feed free of antimicrobials, three groups were offered feed medicated with 50 ppm of ENR starting on weaning day for 5, 7 and 10 days respectively, three groups were offered feed medicated with 50 ppm of ENR starting 7 days post weaning for 5, 7 and 10 days respectively, and were compared with regard to the appearance of clinical signs, mortality, weight gain and feed conversion. The results showed that all ENR treatments reduced the incidence and severity of diarrhoea. Mortality was similar in all ENR treatments, but in the groups where the ENR was added for 10 days immediately after weaning and/or 7 daps post meaning for 7 and 10 days respectively was lower compared to the negative control group (P < 0.05). The evaluation of the weight gain data, as well as feed conversion ratio indicated that the sis treated groups performed remarkably better than the control group (P < 0.05). No ETEC were detected on days 21 and 28 in all ENR groups contrary to the untreated control. It was concluded that a strategic medication initiated 7 days post weaning with 50 ppm of ENR and only for 7 and 10 days period of rime is a useful tool in controlling PWDS due to ETEC.
