Esophageal opening of stomach with no keratinization or ulceration (keratinization score of 1 and ulcer score of 1 for an ulcer index score of 2). Keratinization and ulceration were scored by a single person at the time of slaughter from 4 pigs in each pen. Keratinization scores were assigned on a scale from 1 to 4 with 1 being normal or no keratinization of the esophageal region (as shown above), 2 being keratin covering <25% of the esophageal region, 3 being keratin covering 25 to 75% of the esophageal region, and 4 being keratin covering >75% of the esophageal region. Ulcer scores were also assigned on a scale from 1 to 4 with 1 being no ulcers present, 2 being ulceration affecting <25% of the esophageal region, 3 being ulceration affecting 25 to 75% of the esophageal region, and 4 being ulceration affecting >75% of the esophageal region. An index of stomach morphology was developed by adding a pig’s ulcer and keratinization scores. An additional score of 4 was added to each pig that had an ulceration score greater than 1.