Guidance surrounding equine slaughter varies globally and lacks published evidence, limiting practical application, causing industry confusion and potentially compromised welfare at all stages of the slaughter process, both ante- and post-mortem. Existing research in this field was systematically reviewed, with gaps in the literature assessed. Four databases were searched: PubMed, CAB Abstracts, Science Direct and Google Scholar, using a combination of different search terms. Predetermined inclusion and exclusion criteria were applied with studies required to be novel research, on the welfare of equids or comparable species, relevant to the research question. Full articles were assessed for reliability, repeatability, potential bias and study design.
In total, 2194 articles were screened, and an additional 35 articles were identified via peer-networks and after a snowball search of reference lists. After screening, 105 studies were identified for inclusion in the review. Of these, 101 (96%) were peer-reviewed journal articles and 4 (4%) were grey literature. Thirty-two (30%) looked at equid slaughter specifically with conflicting findings regarding slaughter efficacy. Similar to other species, there was overall agreement on horses showing stress-related behaviour prior to slaughter. Most studies (n = 76, 72%) were conducted in High-Income Countries and not countries where equid slaughter is estimated to be most prolific. There was no published research on the efficiency of stunning or slaughter of donkeys or mules. In conclusion, this systematic review found a shortage of published research assessing equid welfare at slaughter, particularly donkeys and mules in low-income countries, highlighting the need to urgently develop an evidence base for improving guidance in this area.