TWU Local 100 said the carriage horse's cause of death was determined following a necropsy at Cornell University Collage of Veterinary Medicine.

On Tuesday, a carriage horse in Manhattan collapsed and died on the way to its stable, according to a local union. Authorities learned of the incident around 2:30 p.m. after receiving a 911 call requesting assistance at the corner of West 51st Street and 11th Avenue in midtown.

The death of the 15-year-old mare named Lady was being investigated by the city’s health department, officials said.