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Equine veterinary journal2025; doi: 10.1111/evj.70100

Pre-operative feeding effects on post-anaesthetic colic and faecal output in horses.

Abstract: Post-anaesthetic colic (PAC) is a complication in horses undergoing general anaesthesia (GA). Various preoperative feeding strategies are used in equine practice, yet their impact on PAC remains unclear. Objective: To identify perioperative risk factors associated with PAC and evaluate the influence of preoperative fasting on PAC prevalence and faecal output. Methods: Retrospective cohort study. Methods: Medical records of horses undergoing non-abdominal surgery under GA were reviewed. Horses were categorised into fasted and non-fasted groups based on their pre-anaesthetic feeding regimen. Multivariable logistic regression was used to identify variables associated with PAC. Differences in faecal output and water intake between groups were analysed using a two-tailed hypothesis test. Results: A total of 620 cases were included. Fasting (odds ratio [OR] 2.7, 95% CI 1.4-5.5, p = 0.005), increased surgery duration (per minute) (OR 1.01, 95% CI 1.002-1.02, p = 0.017) and increasing age (OR 1.08, 95% CI 1.02-1.15, p = 0.012) were significantly associated with PAC. Non-fasted horses passed significantly more manure post-operatively. Median (IQR) manure production per hour was 0.44 (0.31-0.61) piles in non-fasted versus 0.38 (0.25-0.50) piles in fasted horses during the first 24 h post-anaesthesia (p < 0.001) and 0.53 (0.42-0.67) versus 0.50 (0.36-0.63) in the second 24 h post-anaesthesia (p = 0.04). Water intake 12 h pre-anaesthesia was also higher in non-fasted horses (1.02 [0.73-1.75] L/h) compared to fasted horses (0.88 [0.53-1.75] L/h; p < 0.001). Conclusions: Poor overall accuracy of the predictive model obtained. The retrospective design of the study may introduce bias due to possible inconsistencies in medical records. Conclusions: Pre-operative fasting was associated with increased risk of PAC and reduced faecal output in horses. These findings support reconsidering fasting practices in equine anaesthesia.
© 2025 EVJ Ltd.
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Publication Date: 2025-10-01 PubMed ID: 41032053DOI: 10.1111/evj.70100Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Overview

  • This study investigated how preoperative feeding affects the likelihood of post-anaesthetic colic (PAC) and fecal output in horses undergoing general anaesthesia for non-abdominal surgeries.
  • The research analyzed medical records to determine if fasting before anesthesia increased PAC risk and altered postoperative manure production and water intake.

Background

  • Post-anaesthetic colic (PAC) is a known complication in horses following general anaesthesia (GA), leading to discomfort and potential health risks.
  • In equine practice, different preoperative feeding protocols are implemented, including fasting periods, but the effect of these practices on PAC is not well defined.

Research Objectives

  • Identify perioperative risk factors associated with PAC in horses undergoing GA for non-abdominal surgeries.
  • Evaluate the influence of preoperative fasting on the prevalence of PAC and fecal output post-surgery.

Methods

  • A retrospective cohort study was conducted by reviewing medical records of 620 horses that underwent non-abdominal surgeries under GA.
  • Horses were divided into two groups based on their pre-anaesthetic feeding regimen: fasted and non-fasted.
  • Logistic regression analysis was used to identify variables significantly associated with PAC.
  • Differences in fecal output (manure piles per hour) and water intake 12 hours prior to anaesthesia were analyzed between groups using two-tailed hypothesis tests.

Key Findings

  • Fasting significantly increased the odds of developing PAC:
    • Odds ratio (OR) of 2.7 indicating fasted horses were approximately 2.7 times more likely to experience PAC compared to non-fasted horses.
    • Confidence interval (95% CI) ranged between 1.4 and 5.5, and the p-value was statistically significant at 0.005.
  • Longer surgery duration was also associated with a slight increase in PAC risk (OR 1.01 per minute).
  • Older horses had a higher likelihood of PAC (OR 1.08 per year increase in age).
  • Non-fasted horses produced significantly more manure postoperatively:
    • During the first 24 hours post-anaesthesia, non-fasted horses produced a median of 0.44 manure piles per hour compared to 0.38 in fasted horses (p < 0.001).
    • During the second 24 hours, non-fasted horses produced 0.53 piles per hour versus 0.50 in fasted horses (p = 0.04).
  • Water intake 12 hours before anaesthesia was higher in non-fasted horses (median 1.02 L/h) than in fasted horses (0.88 L/h), with p < 0.001.

Implications and Conclusions

  • The study suggests that preoperative fasting increases the risk of PAC and reduces postoperative fecal output in horses undergoing GA.
  • Non-fasted horses had better hydration levels pre-anaesthesia, which may contribute to improved gut motility after surgery.
  • Despite significant associations found, the researchers noted the overall predictive model was of poor accuracy for individual prediction.
  • Retrospective study design limitations were acknowledged, including possible inconsistencies and bias in medical records that might affect results.
  • Findings support reconsidering standard fasting practices in equine anaesthesia to potentially reduce PAC occurrence and promote better postoperative digestive function.

Cite This Article

APA
Lopes A, Aitkin E, Louro LF. (2025). Pre-operative feeding effects on post-anaesthetic colic and faecal output in horses. Equine Vet J. https://doi.org/10.1111/evj.70100

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English

Researcher Affiliations

Lopes, Ana
  • Liphook Equine Hospital, Liphook, Hampshire, UK.
Aitkin, Ella
  • Liphook Equine Hospital, Liphook, Hampshire, UK.
Louro, Luis Filipe
  • School of Veterinary Science, Leahurst Campus, University of Liverpool, Neston, Cheshire, UK.

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