The Colorado Department of Agriculture is encouraging horse owners to consult their veterinarians about whether to vaccinate those horses against rabies. State officials issued that advice, along with cautioning the owners of pets and livestock, after a horse in eastern Arapahoe County tested positive for rabies earlier this month. That case came less than a year after a horse in El Paso County was euthanized in September 2009, with subsequent tests determining it was infected with rabies. Colorado Department of Public Health and Environment officials have said that earlier horse was believed to have been exposed in