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Monitoring Welfare Procedures for Slaughter of Cattle

29 December 2013

Essential checks should be made during the slaughter of cattle to assess the consciousness, unconsciousness or death of an animal to ensure welfare standards.

According to a study carried out for the European Food Safety Authority, these checks - toolboxes of welfare indicators – should be used for both slaughter with the use of a captive bolt stunner and without stunning.

In the case of slaughter with captive bolt stunning, the opinion proposes a toolbox of indicators and the outcomes to be used to assess consciousness in bovine animals at three key stages of monitoring:

  1. after stunning and during shackling and hoisting;
  2. during neck cutting or sticking; and
  3. during bleeding.

For slaughter of bovines without stunning, a set of indicators and outcomes are proposed in another toolbox to be used for:

  1. assessing unconsciousness, before releasing bovines from restraint; and
  2. confirming death before carcass dressing begins.

The recommendations follow a request from the European Commission (EC),for the Panel on Animal Health and Welfare to deliver scientific opinions on monitoring procedures at slaughterhouses for different animal species, stunning methods and slaughter without stunning.

In particular, the opinions will

  1. provide indicators assessing signs of (a) consciousness, in the case of slaughter with stunning, and (b) unconsciousness and (c) death of the animals, in the case of slaughter without stunning, which have been selected based on their performance (i.e. the sensitivity, specificity and feasibility of the indicator);
  2. indicate the most common risk factors and their welfare consequences to determine the circumstances of the monitoring procedures; and
  3. provide examples of sampling protocols, based on different possible scenarios.

The current opinion deals with the assessment of consciousness in bovines after stunning with penetrative captive bolt and the assessment of unconsciousness and death in bovines during slaughter without stunning.

The Working Group agreed that although the tradition is to look for outcomes of unconsciousness in bovines following stunning, the risk of poor welfare can be detected better if bovine welfare monitoring was focused on detecting consciousness, i.e. ineffective stunning or recovery of consciousness.

Therefore, the indicators were phrased neutrally (e.g. corneal reflex) and the outcomes were phrased either suggesting unconsciousness (e.g. absence of corneal reflex) or suggesting consciousness (e.g. presence of corneal reflex).

This approach is used commonly in animal health studies (e.g. testing for the presence of a disease) but very new to animal welfare monitoring in slaughterhouses.

A toolbox of selected indicators is proposed to check for signs of consciousness in bovines after penetrative captive bolt stunning; a different toolbox of indicators is proposed for confirming unconsciousness as well as death of the animals following slaughter without stunning.

Various activities (two stakeholder consultations, a systematic literature review, an online survey addressed to experts involved with monitoring welfare at slaughter) were carried out in order to obtain information on the sensitivity, specificity and feasibility of the indicators.

Based on such information, the most appropriate indicators were selected and a toolbox of indicators to be used in monitoring procedures was proposed.

The use of animal-based indicators is similar to the use of a diagnostic or statistical ‘test’ with either a positive or negative outcome.

In the case of stunning of animals, the major interest is to detect the undesired outcome, namely the presence of consciousness in animals.

The toolbox proposes respective indicators and their outcomes.

In the case of slaughter without stunning, the interest is to detect whether the animals become unconscious and to detect when the animal dies.

However, the indicators applied for this task also have to correctly detect animals as conscious or alive. In the case of slaughter without stunning, therefore, the toolbox proposes respective indicators and their outcomes.

Each of the toolboxes provides a set of recommended indicators and another set of additional indicators.

The people responsible for monitoring have to choose the most appropriate set of indicators (at least two indicators) from these toolboxes according to their expertise and the available infrastructure in the slaughterhouse.

Toolboxes for Slaughter with Prior Stunning

After stunning of the animals prior to slaughter the indicators should be repeatedly checked to detect signs of consciousness through the three key stages of monitoring during the slaughter process: after stunning (between the end of stunning and shackling), during neck cutting or sticking and during bleeding.

The recommended indicators in Toolbox 1 (for monitoring after stunning) are posture, breathing, tonic seizure and the corneal reflex. Additionally, the indicators muscle tone, eye movements and vocalisation may be used.

In the case of Toolbox 2 (for monitoring at neck cutting or sticking), the recommended indicators are body movements, muscle tone and breathing. Additionally, eye movements, corneal or palpebral reflex and spontaneous blinking may be used.

For Toolbox 3 (for monitoring during bleeding) the recommended indicators are muscle tone, breathing and spontaneous blinking. There are no additional indicators.

Toolboxes for Slaughter without Stunning

In the case of slaughter without stunning, all bovines should be checked until they become unconscious, before being released from the restraint; and death should be confirmed before starting carcass dressing.

Moreover, consciousness or life in checked animals should be correctly identified.

On this basis, the indicators were selected for the toolboxes. In addition, experts felt that carotid artery ballooning (carotid artery aneurysms and occlusion), which is a major risk factor prolonging the time to unconsciousness or recovery of consciousness in bovines subjected to slaughter without stunning, should be included in these toolboxes such that people responsible for animal welfare monitoring will be able to identify the risk and take the necessary action.

The recommended indicators in Toolbox 4 (for monitoring unconsciousness before release from the restraint) are breathing and muscle tone. Additionally, posture, corneal or palpebral reflex may be used.

Toolbox 5 (for monitoring death before carcass dressing begins) recommends bleeding, muscle tone and pupil size as indicators to check for death.

The personnel performing pre-slaughter handling, stunning, shackling, hoisting and/or bleeding will have to check all the animals to rule out the presence of consciousness following captive bolt stunning or to confirm unconsciousness and death during slaughter without stunning.

The person in charge of monitoring the overall animal welfare at slaughter (i.e. the animal welfare officer) has to check a certain sample of slaughtered animals for approval.

A mathematical model is proposed which can be used to calculate the sample size that he/she needs to check at a given throughput rate (total number of animals slaughtered in the slaughter plant) and tolerance level (number of potential failures—animals that are conscious after captive bolt stunning.

Finally, different risk factors and scenarios are proposed to define, in addition to a ‘normal’ sampling procedure, a ‘reinforced’ protocol to be used if required by the particular circumstances and needs of the slaughterhouse.

December 2013

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