Document type: systematic review of the scientific literature published in Frontiers in Veterinary Science
Authors: Haut SR, Parmentier T, Fisher RS, and Khalil NM
Abstract in French (translation): Electrophysiological evidence of loss of consciousness in cattle during slaughter with or without stunning: a systematic review and methodological overview
. Background: Slaughter without prior stunning, as practiced in accordance with Jewish and Islamic religious rites, raises specific animal welfare concerns, particularly regarding the time interval between the incision and loss of consciousness (LOC). LOC marks the point at which cortical processing necessary for perception—including the perception of pain—is no longer possible. Quantifying the time to loss of consciousness in animals is a challenge. To date, the most direct and potentially most objective way to achieve this is through the use of electrophysiological methods. These methods are the main focus of this article.
Methods: This article offers a concise discussion of electrophysiology as applied to slaughter, thereby filling a critical gap in the fundamental electrophysiological knowledge necessary for interpreting PDC and insensibility in the veterinary literature. Next, using a systematic approach guided by the PRISMA principles, this review synthesizes the neurophysiological data regarding the PDC latency in cattle. A literature search was conducted using PubMed/MEDLINE, Web of Science, the Cochrane Library, and Google Scholar (up to December 2025). Experimental studies conducted on cattle and using EEG, ECoG, or evoked potentials were included, while non-cattle studies, those focusing solely on behavior, or those with methodological shortcomings were excluded. Nine studies were selected, and the risk of bias was assessed using the ROBINS-I criteria.
Results: The overall risk of bias for all included studies was judged to be moderate. Studies using electrocorticography (ECoG) reported electrophysiological markers consistent with a loss of consciousness occurring between 4.4 and 13 seconds after the incision, with mean values ranging from 7.5 to 10.8 seconds. The reported time intervals vary from one study to another, particularly those using scalp EEG, likely due to methodological differences and limitations.
Conclusions: The highest-quality available electrophysiological data suggest that loss of consciousness occurs rapidly after slaughter without stunning.
Preview:
Within the framework of the European Union's Common Agricultural Policy (CAP), the Ministry of Agriculture, Agri-food and Food Sovereignty (MAAFS) commissioned an evaluation of the impact of the CAP Strategic Plan (CSP) on animal welfare in France [...] This evaluation was conducted from a thematic perspective focusing on animal welfare and covers the years 2023 and 2024, corresponding to the first two effective years of programme implementation. The evaluation work makes it possible to analyse the contribution of CAP interventions to animal welfare, as well as their coherence and complementarity with other relevant measures. The evaluation was carried out over a 12-month period (January 2025-January 2026) and structured into three phases: the scoping phase (January-March 2025), the data collection and analysis phase (April-September 2025), and the finalisation and recommendations phase (October 2025-January 2026). [...] Background: Slaughter without prior stunning as practiced under Jewish and Islamic religious law raises certain particular animal welfare issues, notably the time between the incision and loss of consciousness (LOC). LOC marks the point at which cortical processing required for perception, including pain, is no longer possible. Quantifying time to LOC in animals is challenging. To date, the most direct and potentially objective means of doing so is the use of electrophysiologic methods. These are the focus of this paper.
Methods: This paper includes a concise discussion of electrophysiology as applied to slaughter, addressing a critical gap in foundational electrophysiologic knowledge required to interpret LOC and insensibility in the veterinary literature. Then, using a PRISMA-guided systematic approach, this review synthesizes neurophysiologic evidence on time to LOC in cattle. A review was conducted using PubMed/MEDLINE, Web of Science, Cochrane Library, and Google Scholar (through December 2025). Experimental cattle studies using EEG, ECoG, or evoked potentials were included, while non-bovine, behavioral-only, or methodologically insufficient studies were excluded. Nine studies were included, and risk of bias was assessed using ROBINS-I.
Results: Overall risk of bias across included studies was judged to be moderate. Studies using electrocorticography (ECoG) reported electrophysiologic markers consistent with LOC occurring between 4.4 and 13 seconds after incision, with mean values ranging from 7.5 to 10.8 seconds. Reported times vary across studies, particularly those using scalp EEG, likely due to methodological differences and limitations.
Conclusions: The highest-quality available electrophysiologic data, suggests that LOC occurs rapidly following slaughter without stunning.
