# Donkey and Hybrid Anaesthetic Mortality in an Observational, Prospective, Multicentre Cohort Study

## TL;DR

This study reports on the mortality rates of donkeys and hybrids under general anesthesia or sedation, finding higher mortality in hybrids compared to donkeys.

## Contribution

The first worldwide study to examine anaesthetic mortality in donkeys and donkey-horse hybrids.

## Key findings

- General anaesthesia in donkeys had a 1.0% mortality rate, while hybrids had a higher 3.6%.
- Standing sedation had lower mortality rates, with donkeys at 0.7% and no hybrid deaths observed.
- Hybrid mortality appeared higher than in donkeys, but data is limited for definitive conclusions.

## Abstract

Anaesthetic mortality in donkeys and donkey–horse hybrids has not previously been specifically examined. The aim of this worldwide observational, prospective, multicentre cohort study was to report on mortality in the 7 days following a general anaesthetic or standing sedation in donkeys and hybrids. Data were collected as part of the fourth Confidential Enquiry into Perioperative Equine Fatalities (CEPEF4). A total of 825 cases were included, with 757 donkeys and 68 hybrids. Of these cases, 616 donkeys and 56 hybrids underwent a general anaesthetic. The overall mortality rate for general anaesthesia in donkeys in this study was 1.0% and was higher in hybrids at 3.6%. There were 141 standing sedations performed in donkeys and 12 in hybrids. Mortality rates for standing sedations were lower, with the donkey mortality rate of 0.7%, and no hybrid mortality was seen in the study. Donkey mortality appears to show similar trends to those of the horse, whilst hybrid mortality appears to be higher. However, the numbers are too low to draw definitive conclusions. Further details around the general anaesthesia and standing sedation of donkeys and hybrids are described in this paper.

Equid anaesthetic mortality is of interest to practitioners. Data for donkey and hybrid mortality have not been specifically described. The main aim of this worldwide observational, prospective, multicentre cohort study was to report on mortality in the 7 days following a general anaesthetic or standing sedation in donkeys and hybrids. This study hypothesised that donkeys and hybrids would have higher mortalities compared to horses. Data were collected as part of the fourth Confidential Enquiry into Perioperative Equine Fatalities (CEPEF4). A total of 825 cases were included, with 757 donkeys and 68 hybrids. Overall, 616 donkeys and 56 hybrids underwent a general anaesthetic. The overall mortality rate for general anaesthesia in donkeys was 1.0% and 3.6% in hybrids. In total, 141 standing sedations were performed in donkeys and 12 in hybrids. Mortality rates for standing sedations were lower, with the donkey mortality rate as 0.7%, and no hybrid mortality was seen. The mortality for donkeys for general anaesthesia appeared similar to the horse, whilst hybrid mortality was higher. COLIC vs. NON-COLIC DEATHs and EUTHANASIAs were also examined in the study. Mortality for standing sedations was lower compared to general anaesthesia. However, the numbers are too low to draw definitive conclusions; further investigation is required.