Stunning of pigs with different gas mixtures: Behavioural and physiological reactions

The present study used thirty-one pigs to investigate induction of unconsciousness and behavioural reactions in different gas mixtures: 80% CO2/air, 90 s; 40% CO2/30% O2/air, 180 s; 70% N2O/30% CO2, 90 s. All pigs lost consciousness. All presented respiratory difficulties and most pigs involuntary m...

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Bibliographic Details
Published in:Meat science 2021-05, Vol.175, p.108452-108452, Article 108452
Main Authors: Terlouw, E.M. Claudia, Deiss, Véronique, Astruc, Thierry
Format: Article
Language:English
Subjects:
Animal biology
Behaviour
Gas stunning
Life Sciences
Physiology
Pigs
Stress
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Summary:The present study used thirty-one pigs to investigate induction of unconsciousness and behavioural reactions in different gas mixtures: 80% CO2/air, 90 s; 40% CO2/30% O2/air, 180 s; 70% N2O/30% CO2, 90 s. All pigs lost consciousness. All presented respiratory difficulties and most pigs involuntary muscle contractions, often before loss of standing posture. Between mixtures, average latencies of certain behaviours and delays between behaviours differed. Following immersion, blood pH was lower than normal. The low pH induced by the CO2/O2/air mixture was physiologically associated with hyperoxemia. Relationships between blood gases, different behavioural and heart rate responses are discussed. In conclusion, all mixtures caused discomfort due to respiratory difficulties and the addition of O2 or N2O to the CO2 mixture did not present an advantage. •Immersion in CO2/air, CO2/O2/air, and N2O/CO2 induced unconsciousness.•In the CO2/O2/air mixture, hyperoxemia contributed to low blood pH.•All mixtures caused respiratory difficulties and involuntary muscle contractions.•All mixtures caused discomfort.•The addition of O2 or N2O to the CO2 mixture did not present an advantage.
ISSN:0309-1740
1873-4138
DOI:10.1016/j.meatsci.2021.108452