Broiler stunning methods and their effects on welfare, rigor mortis, and meat quality

Joseph, P.; Schilling, M. Wes; Williams, J.B.; Radhakrishnan, V. M.; Battula, V.; Christensen, K.; Vizzier-Thaxton, Y.; Schmidt, Ty B

doi:10.1017/s0043933913000093

Cited by 25 publications

(20 citation statements)

References 61 publications

(76 reference statements)

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“…To be humane, stunning methods should produce insensibility with minimum welfare concerns (Joseph et al, 2013). Like CAS, LAPS has many advantages for commercial poultry slaughter, including avoiding live shackling and ensuring every bird is stunned.…”

Section: Headshaking Mandibulation and Open Bill Breathing (Or Othermentioning

confidence: 99%

Behavioural responses of broiler chickens during low atmospheric pressure stunning

Mackie

McKeegan

2016

Applied Animal Behaviour Science

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31Low atmospheric pressure stunning (LAPS) is a new irreversible stunning method for broiler chickens 32 (Gallus gallus domesticus), which has the potential to improve welfare during routine slaughter. 33During LAPS, birds are placed in a hypobaric chamber that allows oxygen to be gradually removed 34 from the environment by the controlled removal of air; the staged process takes 280s and reaches final 35 decompression pressure that is 80.6 kPa below atmospheric pressure (nominally 101.3 kPa for an 36 absolute vacuum pressure of 20.7 kPa). In this study, the behaviour of broilers (50 individuals and 50 37 focal birds killed in groups of 20) was observed during LAPS. Latencies, total durations, single bout 38 durations and number of bouts were recorded for all behaviours. Three different decompression 39 curves were applied during the process (based on automatically applied settings related to ambient 40 temperature) and their effects on behaviour were investigated. Not all birds displayed all behaviours, 41 but a subset of behaviours (ataxia, loss of posture, clonic and tonic convulsions and leg paddling) 42 occurred in a consistent sequence. In individuals, mandibulation, headshaking and open bill breathing 43 occurred earliest at 44.5s ± 31.6s, 50.8s ± 38.3s and 57.4s ± 35.8s respectively after LAPS began. 44Ataxia was observed on average at 57.3s ± 11.5s, with birds killed at colder temperatures taking 45 slightly longer to succumb to ataxia than those at warmer temperatures. Loss of posture (LOP) is 46 regarded as a behavioural marker for loss of consciousness and it occurred on average at 80.7s ± 47 17.7s. Clonic and tonic convulsions were displayed after LOP at 110.5s ± 37.6s and 117.4s ± 28.8s 48 after LAPS onset respectively. Mean time to motionless was 199.4s ± 21.3s. The group data were 49 largely similar to that of individuals but were less reliable due to focal birds being obscured by 50 neighbours. Based on LOP, the data suggest that birds are in a conscious state for longer during 51 LAPS than in controlled atmosphere stunning with inert gases, but although the induction to 52 unconsciousness is more gradual, other behavioural responses were equivalent. The occurrence of 53 mandibulation, head shaking, and open bill breathing may be an indication of reduced welfare or may 54 be indications of a non-painful physiological responses to hypoxia in a hypobaric atmosphere. These 55 behaviours occurred at similar levels as seen in CAS with inert gases in poultry and the lack of escape 56 3 behaviours as well as absence of signs of severe dyspnoea suggest that LAPS is a humane approach to 57 stunning of poultry. 58Key words: Animal welfare, hypobaric hypoxia, humane slaughter, and loss of posture, low 59 atmosphere pressure stunning 60 61

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Section: Headshaking Mandibulation and Open Bill Breathing (Or Othermentioning

confidence: 99%

Behavioural responses of broiler chickens during low atmospheric pressure stunning

Mackie

McKeegan

2016

Applied Animal Behaviour Science

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“…Furthermore, handling of poultry immediately prior to slaughter, such as hanging and stunning, contributes to the frequency of traumatic injuries, especially to the limbs [18,19]. Gaseous stunning methods that render birds unconscious before hanging minimize injuries sustained from wing flapping [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Traumatic Injuries Detected during Post-Mortem Slaughterhouse Inspection as Welfare Indicators in Poultry and Rabbits

Válková

Voslářová

Večerek

et al. 2021

Animals

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The findings of traumatic injuries during post-mortem inspection in slaughterhouses reflect the level of pre-slaughter handling of animals at the farm and during transport to the slaughterhouse. The prevalence of traumatic injuries was monitored in poultry (1,089,406,687 broiler chickens, 20,030,744 laying hens, 1,181,598 turkeys, 37,690 geese, 28,579,765 ducks) and rabbits (1,876,929) originating from farms in the Czech Republic and slaughtered in slaughterhouses in the Czech Republic between 2010 and 2019. The greatest incidence of traumatic injuries was found in laying hens (2.80%) and rabbits (1.52%); while the overall incidence of trauma was less than 0.5% in other species and categories. The results show that the current rearing conditions and/or pre-slaughter handling of poultry and rabbits particularly affect the limbs; traumatic findings were significantly (p < 0.01) more frequent on the limbs than on the trunk in all species studied. In poultry, traumatic findings on the trunk were orders of magnitude lower to negligible, so the focus should be on preventing injuries to the limbs. In rabbits, the difference was less pronounced, and many injuries were found on both limbs (0.83%) and trunk (0.69%). Our results emphasize the need to reconsider both housing and pre-slaughter handling methods to determine minimum standards for the protection of rabbits, which are still lacking in European legislation.

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“…Joseph et al. ( 2013 ) noted that the most common stunning process is electric stunning ( ES ) in which the chicken are either dumped/tipped out or extracted by hand from the transport crates, and placed upside down in shackles, and passed through a conducting salt water bath with an applied voltage sufficient to cause unconsciousness and/or death. Recognizing that handling and being shackled upside down stresses the birds (Gentle and Tilston, 2000 ); alternative methods for stunning have been developed, including controlled atmosphere stunning ( CAS ) and LAPS (Johnson ( 2014 ).…”

Section: Introductionmentioning

confidence: 99%

Effects of ambient temperature and water vapor on chamber pressure and oxygen level during low atmospheric pressure stunning of poultry

Holloway¹,

Pritchard²

2017

Poultry Science

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The characteristics of the vacuum used in a low atmospheric pressure stunning system to stun (render unconscious) poultry prior to slaughter are described. A vacuum chamber is pumped by a wet screw compressor. The vacuum pressure is reduced from ambient atmospheric pressure to an absolute vacuum pressure of ∼250 Torr (∼33 kPa) in ∼67 sec with the vacuum gate valve fully open. At ∼250 Torr, the sliding gate valve is partially closed to reduce effective pumping speed, resulting in a slower rate of decreasing pressure. Ambient temperature affects air density and water vapor pressure and thereby oxygen levels and the time at the minimum total pressure of ∼160 Torr (∼21 kPa) is varied from ∼120 to ∼220 sec to ensure an effective stun within the 280 seconds of each cycle. The reduction in total pressure results in a gradual reduction of oxygen partial pressure that was measured by a solid-state electrochemical oxygen sensor. The reduced oxygen pressure leads to hypoxia, which is recognized as a humane method of stunning poultry. The system maintains an oxygen concentration of <5% for at least 2 minutes, which ensures that birds are irreversibly stunned. Calculated pump down (pressure versus time) data match experimental data very closely because the programmable logic controller and the human machine interface enable precise and accurate control. The vacuum system operates in the turbulent viscous flow regime, and is best characterized by absolute vacuum pressure rather than gauge pressure. Neither the presence of broiler chickens nor different fore-line pipe designs of four parallel commercial systems affected the pressure-time data. Water in wet air always reduces the oxygen concentrations to a value lower than in dry air. The partial pressure of water and oxygen were found to depend on the pump down parameters due to the formation of fog in the chamber and desorption of water from the birds and the walls of the vacuum chamber.

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Broiler stunning methods and their effects on welfare, rigor mortis, and meat quality

Cited by 25 publications

References 61 publications

Behavioural responses of broiler chickens during low atmospheric pressure stunning

Behavioural responses of broiler chickens during low atmospheric pressure stunning

Traumatic Injuries Detected during Post-Mortem Slaughterhouse Inspection as Welfare Indicators in Poultry and Rabbits

Effects of ambient temperature and water vapor on chamber pressure and oxygen level during low atmospheric pressure stunning of poultry

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