On Monday in Part 4 of this excerpt from the new book Equine ER, we took a deeper look at the prison farm program where an inmate met Marching Orders, the stoic Thoroughbred with the big heart. Today, we go back into the operating room and find out what the surgeon discovered with Marching Orders on the table.

In the operating room, what surgeon Scott Hopper found was a diaphragmatic hernia Ð a hole in the diaphragm between the chest and the abdominal cavity Ð and a section of the small colon had gotten trapped inside the opening. The ultrasound hadn’t picked it up because of the amount of gas distention and the hernia’s location, higher on the diaphragm, more toward the horse’s back. It wasn’t your everyday colic.

Dr. Scott Hopper operates on Thoroughbred Marching Orders.

Horses can live with diaphragmatic hernias for years (some are born with them). One original cause of a hernia is trauma Ð getting kicked, for example.  Often, diaphragmatic hernias are small, and because the lung capacity of a horse is one of the largest of all species, horses don’t necessarily need all that capacity to function, especially a horse like Marching Orders who was retired and not running on the track