The effects of stress on gastric ulceration, T3, T4, reverse T3 and cortisol in neonatal foals.

This research sought to understand the effects of severe physiological stress on the occurrence of stomach ulcers in neonatal foals, by measuring their levels of triiodothyronine (T3), reverse T3, thyroxine (T4), and cortisol, and endoscopic examination of their stomachs. The study observed a higher occurrence of stomach lesions, especially in the gastric glandular mucosal area, in stressed foals, but found stress had little effect on developing lesions on the squamous mucosal portion.

Research objective and methodology

• The study aimed to investigate the relationship between severe physiological stress and the frequency of stomach (gastric) ulcers in neonatal foals (young horses).
• To achieve this, sixteen disease-stressed foals underwent endoscopic examination of their stomachs and had their blood assayed for levels of triiodothyronine (T3), reverse T3 (rT3), thyroxine (T4), and cortisol.
• The observations and results were then compared with eight controls of the same age, to ascertain the effects of stress.

Key Findings

• Six foals were found to have abnormal cortisol levels, seven had abnormal T3, and twelve had abnormal T4 levels.
• Out of thirteen foals, eleven had rT3 levels outside of what would be expected in the 95 per cent confidence interval for clinically normal foals of similar ages.
• Stress appeared to lead to a higher incidence of gastric lesions, specifically in the gastric glandular mucosal part of the stomach, with 40 percent of the stressed foals developing these lesions.
• In contrast, the levels of squamous mucosal lesions were relatively unchanged from those reported previously, suggesting that stress has negligible effect on the formation of these types of lesions.

Comparison with Previous Studies

• The greater percentage (40%) of gastric glandular mucosal lesions in stressed foals as observed in this study starkly contrasts with previous findings, which reported a low occurrence rate (3%) of gastric mucosal lesions.

Implications of the Study

• The study shows a clear correlation between physiological stress and a higher frequency of gastric ulcers in neonatal foals, which suggests that managing stress could likely reduce the risk of such health complications.
• However, the stress doesn’t seem to significantly affect the incidence of squamous mucosal lesions. Therefore, other factors aside from stress may contribute to the development of these lesions and need to be further identified and investigated.