Abstract
Despite several millions of working equids worldwide, there are few published studies regarding the epidemiology of their health and welfare. Data collected by non-governmental organisations (NGOs) operating in the working equid sphere therefore have important epidemiological value and could be used towards animal health surveillance. The aim of this study was to identify common clinical findings and mortality patterns of working equids in low- and middle-income countries and investigate their epidemiology using data collected from an international NGO. A retrospective analysis was conducted to determine the proportion of clinical findings and mortality risk by equid species, year and region. Negative binomial regression models were generated to investigate differences in mortality risk and proportion of key clinical findings between equid species, hemispheres and calendar month. A total of 4,313,606 presentations were reported from 14 countries between January 2005 and March 2021 (mean 22,121; SD ± 7,858 per month). Wounds and abscesses were the most reported clinical finding for all equid species (mean proportion 35%; SD ±0.19 of all findings). A higher proportion of wounds (mean proportion 41.7%; SD±0.2) was recorded in donkeys than mules or horses (P<0.001). Mules had higher reported mortality risk (1.2%; 95% CI 0.94-1.46%) than horses (0.4%; 95% CI 0.36-0.55%; p<0.001) or donkeys (0.2%; 95% CI 0.14-0.22%). Work-related wounds were the predominant finding in working equids, particularly so in donkeys. Prevention strategies should focus on improvements to work equipment and practices for all equids. Future investigations required include refinement of diagnostic approaches for donkeys and investigation of risk factors to understand the higher mortality in mules. Routine monitoring of clinical findings reported by national or international NGOs could be included in animal health surveillance strategies, although standardisation of data for this purpose is needed so that changes in prevalence following implementation of prevention strategies can be monitored.