Final answer:
Gastropexy is the surgical procedure used to prevent gastric torsion in dogs by attaching the stomach to the abdominal wall to prevent it from twisting.
Step-by-step explanation:
The procedure used to prevent gastric torsion, also known as bloat, in large, deep-chested dog breeds is Gastropexy. This surgical procedure involves attaching the stomach to the abdominal wall or the diaphragm to prevent it from twisting. Gastric torsion is a serious and potentially life-threatening condition that occurs when the stomach fills with gas and then twists on itself, which can disrupt blood flow and may lead to stomach tissue death.