Introduction

Ulcers of the esophageal region of the pig stomach are recognized worldwide as an important disease. They are significant because of the high fatality rate associated with the disease. The rate of lesions of the esophageal region of the pig stomach has been increasing since the late 1950's and 1960's as the level of management has become more intense.

In order to study the mechanisms of stomach ulceration, a dietary model was developed that resulted in significant damage to the esophageal region. Composition of stomach contents and stomach tissue in pigs fed finely ground and pelleted (FGP) feed was compared to pigs fed coarsely ground mash (CGM) feed. Almost without exception no damage was observed to the esophageal region in pigs fed the CGM feed. Thus, the comparisons between these two feeds have provided information to describe the mechanisms responsible for stomach damage.

In addition to diet, one condition associated with increased incidence of ulceration is feed withdrawal. Ulcers have been associated with concurrent disease and it is possible that the association is related to the impact of disease on feed intake. In general, an animal often spikes a fever and decreases feed intake in association with a disease challenge.

The objective of this study was to evaluate the impact of diet on stomach damage in response to feed withdrawal as well as recovery from feed withdrawal after a week of refeeding.

Materials and Methods

Sixty-two crossbred barrows were used in the experiment. The experiment was conducted in two replicates. There were 30 pigs in the first replicate and 32 pigs in the second replicate. In replicate 1, 14 pigs were fed a finely ground and pelleted diet (FGP; 446 microns) and 16 pigs were fed a coarsely ground meal diet (CGM; 1026 microns) for three weeks. Feed was then removed for 48 hours. At the end of 48 hours, pigs were refed either their original feed or the opposite feed for one week.

Four animals on each diet were killed after the initial 3-week feeding period and 4 from each diet group were killed after 48 hours without feed. Four of the pigs that were fed initially the FGP diet were refed the FGP diet and four were refed the CGM diet. Four of the pigs that were fed initially the CGM diet were refed the CGM diet and two were refed the FGP diet. These pigs were killed after a one week refeeding period. Replicate two was identical except that 16 pigs were fed initially the FGP diet and there were four pigs in each subgroup.

Results and Discussion

After three weeks of feeding, pigs fed the FGP diet had significant damage (P<.05) to the esophageal region of the stomach whereas pigs fed the CGM diet did not (Table 1). After 48 hours without feed, the extent of damage was similar for pigs that had been on the CGM or FGP diet, however, slightly worse for the pigs that had been fed the FGP diet. Refeeding the CGM diet for one week promoted healing, regardless of previous diet. The average ulcer score after one week of refeeding was 1.6 for pigs originally on the CGM diet and 2.1 for pigs originally on the FGP diet. In contrast, refeeding the FGP diet for one week resulted in minimal repair.

Summary