A blinded, randomised, placebo-controlled clinical trial was conducted to evaluate the efficacy and safety of
valnemulin hydrochloride premix during an outbreak of epizootic rabbit enteropathy (ERE) when administered in feed for 21 consecutive days after confirmation of the first ERE case. Administration of
valnemulin at 20 and 35 parts per million (ppm) significantly reduced mortality by 11% and 7.6%, respectively, when compared with the non-medicated control group (23% mortality). Non-ERE related adverse events, including
dysbacteriosis, enterotoxaemia and
pneumonia, occurred in all groups at similar frequencies (untreated: 1.8%; 20 ppm
valnemulin: 2.8%; 35 ppm
valnemulin: 1.3%). Administration of
valnemulin did not affect feed consumption or
body weight gain; treated rabbits had sustained
weight gain and feed conversion rates (FCRs). However, from days 7 to 21 of the outbreak, untreated rabbits had significantly lower daily
weight gains and higher FCRs than medicated rabbits, suggesting a protective effect of
valnemulin during the peak of the disease. Untreated rabbits exhibited compensatory growth from days 21 to 28, when the last observation was made. FCRs for the entire study were similar among all three groups. Impaction and diarrhoea were more frequent in untreated animals, with a poor prognosis, while tympanism was more common in
valnemulin-treated rabbits that survived. In conclusion, early administration of
valnemulin hydrochloride premix at 20 or 35 ppm is efficacious and safe for the treatment of naturally occurring ERE.