Safety and Synovial Inflammatory Response After Intra-articular Injection of Botulinum Toxin Type A in Healthy Horses

•There is a lack of information on the safety of botulinum toxin type A (BoNT-A) for intra-articular use in horses.•Intra-articular injection of 50 U of BoNT-A did not produce systemic effects of botulism.•Lameness was not observed in BoNT-A treated joints.•Inflammatory response on BoNT-A-treated joints was similar to those elicited by placebo.