Efficacy and tolerability of early administration of valnemulin hydrochloride premix on epizootic rabbit enteropathy.

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.