Horse Supplements will make your horse strong. However, there are still some illnesses that cannot be addressed with health supplements alone. This can include horse rabies. Stricken horses might express depression, excessive salivation, difficulty swallowing, loss of coordination, aggressive behavior, hyper-excitability, colic, convulsions or paralysis. Death typically happens three to five days after the start of clinical signs, however it can also occur within just 1 day. At present no laboratory tests are available to verify rabies in a live animal.