Clinical field trial to assess the efficacy of two different enrofloxacin (Baytril® 2.5%) oral concentrations against scours in lambs due to E. coli

AIM OF THE STUDY Multicentric, controlled and randomised study was carried out to verify and compare the clinical and bacteriological efficacy of two different oral therapeutic protocols (Baytril® 2.5%, Bayer, Italy) against E. coli induced clinical diarrhoea in lambs. BACKGROUND Infectious diarrhoea of neonatal animals is one of the most common and economically devastating conditions encountered in the animal agriculture industry. Recent studies suggest that 30% of lambs may be affected, with a mortality rate in Europe of 10%. Escherichia coli (E. coli) is considered as the most important bacterial pathogen and diarrhoea-causing E. coli possess colonization antigens or adhesins that enable the bacteria to colonize the small intestines. The K99 (F5) fimbrial antigen has been reported to be associated with a majority of enterotoxigenic E. coli isolated from cases of diarrhoea most commonly in lambs between 2-15 days old. MATERIALS AND METHODS The field trial were carried out on 80 lambs aged between 2-15 days resulted bacteriologically positive to E. coli sensitive to Enrofloxacin. The lambs were submitted to the enrolment visit and enclosed if they showed acute or hyperacute diarrhoea, body temperature higher than 39.6°C, decreased appetite and/or lethargy and/or other general signs of disease. Lambs receiving systemic treatments, either anti-infective or anti-inflammatory, within the previous ten days were excluded. After a randomly allotment to one of two treatment groups (group A: 2.5mg/kg b.w. of Enrofloxacin (Baytril® 2.5%-Bayer) orally once for 3 consecutive days, and group B: 5mg/kg b.w. of Enrofloxacin (Baytril® 2.5%-Bayer) orally once for 3 consecutive days), all lambs received a daily physical examination on days 1 (enrolment day), 2, 3, 5, 7 and 14. The following evaluation parameters were gathered: rectal temperature, general conditions, faecal consistency, dehydration, and on days 1 (before treatment), 5, and 14, faecal swabs to evaluate the bacteriological cure of animals were collected. RESULTS AND CONCLUSION Enrofloxacin (Baytril® 2.5%-Bayer) orally administered improved the general conditions, the faecal consistency and the dehydration state of all animals. Compared to the group A, the lambs receiving double dose of Enrofloxacin showed a significative shorter bacteriological and clinical cure at 5th (P=0.0056) and 3rd day post treatment (PT) (P=0.0015), respectively. Moreover, already after 3 days (PT) a normal faecal consistency was observed in 50% of lambs belonging to the group B in comparison to 10% of animals of group A (P=0.0001). The double oral concentration significantly improved hydration status (P<0.0017): at 5th day (PT) a 72.5% vs 97.5% of lambs had a completely recovery (hydration), respectively in group A and B. The oral administration of Enrofloxacin (Baytril® 2.5%-Bayer) is a quick, practical and efficacious way to treat diarrhoea in lambs due to E. coli. The facility in use (employment) and the attractiveness characterize this product that at the concentration of 5mg/kg b.w can be recommended as a good support for a fast bacteriological and clinical recovery of diarrhoea in lambs.