The crew from Metheringham were called out just before 2pm to an address on Cumberland Avenue in Wellingore, according to Lincolnshire Fire and Rescue.
A spokesman said the firefighters used a type of wrecking crowbar called a hooligan tool and and some wedges to prize the posts wide enough apart to release the trapped dog.
The lucky pet suffered no injuries as a result.
Later in the day, a crew from Sleaford attended a chimney fire at a property on Leas Road, Great Hale.
The incident was reported shortly before 8pm and the crew used chimney gear and a hose to extinguish the fire.