The 15-year-old Standardbred cross horse died due to a small tumor in her adrenal gland that likely caused an aortic rupture, a necropsy found, a TWU representative said.

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.

Supporters of a carriage horse named Lady that collapsed and died in Hell's Kitchen held a rally across the from the stable where she lived.