Jessica Martin

Behavioural, brain and cardiac responses to hypobaric hypoxia in broiler chickens.

A novel approach to pre-slaughter stunning of chickens has been developed in which birds are rendered unconscious by progressive hypobaric hypoxia. Termed Low Atmospheric Pressure Stunning (LAPS), this approach involves application of gradual decompression lasting 280s according to a prescribed curve. We examined responses to LAPS by recording behaviour, electroencephalogram (EEG) and electrocardiogram (ECG) in individual male chickens, and interpreted these with regard to the welfare impact of the process. We also examined the effect of two temperature adjusted pressure curves on these responses. Broiler chickens were exposed to LAPS in 30 triplets (16 and 14 triplets assigned to each pressure curve). In each triplet, one bird was instrumented for recording of EEG and ECG while the behaviour of all three birds was observed. Birds showed a consistent sequence of behaviours during LAPS (ataxia, loss of posture, clonic convulsions and motionless) which were observed in all birds. Leg paddling, tonic convulsions, slow wing flapping, mandibulation, head shaking, open bill breathing, deep inhalation, jumping and vocalisation were observed in a proportion of birds. Spectral analysis of EEG responses at 2s intervals throughout LAPS revealed progressive decreases in median frequency at the same time as corresponding progressive increases in total power, followed later by decreases in total power as all birds exhibited isoelectric EEG and died. There was a very pronounced increase in total power at 50-60s into the LAPS cycle, which corresponded to dominance of the signal by high amplitude slow waves, indicating loss of consciousness. Slow wave EEG was seen early in the LAPS process, before behavioural evidence of loss of consciousness such as ataxia and loss of posture, almost certainly due to the fact that it was completely dark in the LAPS chamber. ECG recordings showed a pronounced bradycardia (starting on average 49.6s into LAPS), often associated with arrhythmia, until around 60s into LAPS when heart rate levelled off. There was a good correlation between behavioural, EEG and cardiac measures in relation to loss of consciousness which collectively provide a loss of consciousness estimate of around 60s. There were some effects of temperature adjusted pressure curves on behavioural latencies and ECG responses, but in general responses were consistent and very similar to those reported in previous research on controlled atmosphere stunning with inert gases. The results suggest that the process is humane (slaughter without avoidable fear, anxiety, pain, suffering and distress). In particular, the maintenance of slow wave EEG patterns in the early part of LAPS (while birds are still conscious) is strongly suggestive that LAPS is non-aversive, since we would expect this to be interrupted by pain or discomfort.

Comparison of novel mechanical cervical dislocation and a modified captive bolt for on-farm killing of poultry on behavioural reflex responses and anatomical pathology

An alternative emergency method for killing poultry on-farm is required following European legislation changes (EU 1099/2009), which heavily restricts the use of manual cervical dislocation. This study investigated the kill efficacy of two mechanical methods that conform to the new legislation: (i) a novel mechanical cervical dislocation device; and (ii) a modified captive-bolt device (Rabbit Zinger™) and manual cervical dislocation (the control). Killing treatments were applied to broilers and layers at two stages of production (broilers: 2–3 and 5 weeks of age; layers: 12–13 and 58–62 weeks), with a total of 180 birds. Latency to abolition of cranial and behavioural reflexes, as well as post mortem analysis of the physiological damage produced, were used to estimate time to unconsciousness and assess kill efficacy. The novel mechanical cervical dislocation device was reliable and a practical method for killing poultry on-farm (100% kill success), with the majority of cranial reflexes showing no significant differences between interval mean durations across killing methods (eg nictitating membrane [mean = 0.7–3.3 s], and rhythmic breathing [mean = 0.0–0.3 s]), however for jaw tone and pupillary reflex, the modified Rabbit Zinger™ had significantly shorter interval mean durations compared to the control and mechanical cervical dislocation device (mean differences: jaw tone = ∼8 s; pupillary = ∼38 s). The novel mechanical cervical dislocation device resulted in consistent anatomical damage to the birds (eg high dislocation of the neck and severing of the spinal cord) compared to the manual method, despite both having 100% success rate, while the modified Rabbit Zinger™ was difficult to operate and resulted in varied anatomical damage. The novel mechanical cervical dislocation device showed promise as a replacement kill method on-farm for poultry.

Evaluation of the potential killing performance of novel percussive and cervical dislocation tools in chicken cadavers.

ABSTRACT 1. Four mechanical poultry killing devices; modified Armadillo (MARM), modified Rabbit Zinger (MZIN), modified pliers (MPLI) and a novel mechanical cervical dislocation (NMCD) gloved device, were assessed for their killing potential in the cadavers of euthanised birds. 2. A 4 × 4 × 4 factorial design (batch × device × bird type + age) was employed. Ten bird cadavers per bird type and age were tested with each of the 4 devices (N = 160 birds). All cadavers were examined post-mortem to establish the anatomical damage caused. 3. NMCD, MARM and MZIN demonstrated killing potential, as well as consistency in their anatomical effects. NMCD had the highest killing potential, with 100% of birds sustaining the required physical trauma to have caused rapid death. 4. The MPLI was inconsistent, and only performed optimally for 27.5% of birds. Severe crushing injury was seen in >50% of MPLI birds, suggesting that birds would die of asphyxia rather than cerebral ischaemia, a major welfare concern. As a result, the MPLI are not recommended as a humane on-farm killing device for chickens. 5. This experiment provides important data on the killing potential of untried novel percussive and mechanical cervical dislocation methods, informing future studies.

Effects of light on responses to low atmospheric pressure stunning in broilers

Abstract Low atmospheric pressure stunning (LAPS) is a novel approach to poultry stunning involving the application of gradual decompression lasting 280 s according to a prescribed pressure curve. The aim of this study was to determine how behavioural, electroencephalogram (EEG) and electrocardiogram (ECG) responses to LAPS are influenced by illumination of the decompression chamber. A secondary aim was to examine responses to the decompression chamber without LAPS being applied, as such a “sham” control has been absent in previous studies. A two by two factorial design was employed, with LAPS/light, LAPS/dark, sham/light and sham/dark treatments (N = 20 per treatment). Broilers were exposed to each treatment in pairs, in each of which one bird was instrumented for recording EEG and ECG. Illumination was applied at 500 lx, and in sham treatments, birds were identically handled but remained undisturbed in the LAPS chamber without decompression for 280 s. Birds which underwent the sham treatment exhibited behaviours which were also observed in LAPS (e.g. sitting) while those exposed to LAPS exhibited hypoxia-related behaviours (e.g. ataxia, loss of posture). Behavioural latencies and durations were increased in the sham treatments, since the whole cycle time was available (in LAPS; birds were motionless by 186 s). Within the sham treatments, illumination increased active behaviour and darkness induced sleep, but slow-wave EEG was seen in both. The pattern of EEG response to LAPS (steep reduction in median frequency in the first 60 s and increased total power) was similar, irrespective of illumination, though birds in darkness had shorter latencies to loss of consciousness and isoelectric EEG. Cardiac responses to LAPS (pronounced bradycardia) closely matched those reported previously and were not affected by illumination. The effects of LAPS/sham treatment primarily reflected the presence/absence of hypoxia, while illumination affected activity/sleep levels in sham-treated birds and slowed time to unconsciousness in birds undergoing LAPS. Therefore, it is recommended that LAPS be conducted in darkness for poultry.

On Farm Evaluation of a Novel Mechanical Cervical Dislocation Device for Poultry

Simple Summary Large numbers of poultry are killed on farm (usually because they are ill or injured) and we have a responsibility to ensure that the methods used have minimal welfare impact. The traditional method of manual cervical dislocation (i.e., “necking” by hand), has been subject to welfare concerns and has recently been restricted by law in Europe, in terms of the number of birds that can be killed with this method per day. Alternative methods need to be developed and these must be humane, practical and reliable in commercial settings. We evaluated the performance and reliability of a novel mechanical cervical dislocation device in comparison with the traditional manual method. We tested the performance of multiple users of each method in commercial laying hen and broiler farm settings. The novel mechanical method was outperformed by the traditional manual method, and there were some issues with training, dependent on the stockworkers’ technique and experience. The results show that while the novel method has the potential to improve welfare, it requires further refinement and training optimization in order to provide a viable alternative to manual cervical dislocation across the poultry industry. Abstract Urgent development of alternative on-farm killing methods for poultry is required following the number restrictions placed on the use of traditional manual cervical dislocation by European Legislation (EU 1099/2009). Alternatives must be proven to be humane and, crucially, practical in commercial settings with multiple users. We assessed the performance and reliability of a novel mechanical cervical dislocation device (NMCD) compared to the traditional manual cervical dislocation (MCD) method. NMCD was based on a novel device consisting of a thin supportive glove and two moveable metal finger inserts designed to aid the twisting motion of cervical dislocation. We employed a 2 × 2 factorial design, with a total of eight stockworkers from broiler and layer units (four per farm) each killing 70 birds per method. A successful kill performance was defined as immediate absence of rhythmic breathing and nictitating membrane reflex; a detectable gap in the vertebrae and only one kill attempt (i.e., one stretch and twist motion). The mean stockworker kill performance was significantly higher for MCD (98.4 ± 0.5%) compared to NMCD (81.6 ± 1.8%). However, the MCD technique normally used by the stockworkers (based previous in-house training received) affected the performance of NMCD and was confounded by unit type (broilers), with the majority of broiler stockworkers trained in a non-standard technique, making adaption to the NMCD more difficult. The consistency of trauma induced by the killing methods (based on several post-mortem parameters) was higher with NMCD demonstrated by “gold standard” trauma achieved in 30.2% of birds, compared to 11.4% for MCD (e.g., dislocation higher up the cervical region of the spine i.e., between vertebrae C0–C1, ≥1 carotid arteries severed), suggesting it has the potential to improve welfare at killing. However, the results also suggest that the NMCD method requires further refinement and training optimization in order for it to be acceptable as an alternative across poultry industry, irrespective of previous MCD technique and training.

Welfare Risks of Repeated Application of On-Farm Killing Methods for Poultry

Simple Summary During poultry production, some birds are killed humanely on farm, usually because they are ill or injured. Recent European Union (EU) legislation has restricted the number of birds that can be killed by manual neck dislocation to 70 birds per person per day. We examined whether this limit is meaningful by investigating the effects of repeated application of two methods of killing (neck dislocation and a percussive method, the CashPoultry Killer). Twelve male stockworkers each killed 100 birds (broilers, laying hens, or turkeys) at a fixed rate with each method. Both methods were highly successful, and reflex and behaviour measures confirmed they caused rapid loss of brain function. Importantly, there was no evidence of reduced performance with time/bird number up to 100 birds with either method. The Cash Poultry Killer caused a more rapid death, but it was prone to technical difficulties with repeated use. Neck dislocation has the important advantage that it can be performed immediately with no equipment, which may make it preferable in some situations. We present the first evidence that, at the killing rates tested, there was no evidence to justify the current EU number limit for performance of neck dislocation to kill poultry on farm. Abstract Council Regulation (EC) no. 1099/2009 on the protection of animals at the time of killing restricts the use of manual cervical dislocation in poultry on farms in the European Union (EU) to birds weighing up to 3 kg and 70 birds per person per day. However, few studies have examined whether repeated application of manual cervical dislocation has welfare implications and whether these are dependent on individual operator skill or susceptibility to fatigue. We investigated the effects of repeated application (100 birds at a fixed killing rate of 1 bird per 2 min) and multiple operators on two methods of killing of broilers, laying hens, and turkeys in commercial settings. We compared the efficacy and welfare impact of repeated application of cervical dislocation and a percussive killer (Cash Poultry Killer, CPK), using 12 male stockworkers on three farms (one farm per bird type). Both methods achieved over 96% kill success at the first attempt. The killing methods were equally effective for each bird type and there was no evidence of reduced performance with time and/or bird number. Both methods of killing caused a rapid loss of reflexes, indicating loss of brain function. There was more variation in reflex durations and post-mortem damage in birds killed by cervical dislocation than that found using CPK. High neck dislocation was associated with improved kill success and more rapid loss of reflexes. The CPK caused damage to multiple brain areas with little variation. Overall, the CPK was associated with faster abolition of reflexes, with fewer birds exhibiting them at all, suggestive of better welfare outcomes. However, technical difficulties with the CPK highlighted the advantages of cervical dislocation, which can be performed immediately with no equipment. At the killing rates tested, we did not find evidence to justify the current EU limit on the number of birds that one operator can kill on–farm by manual cervical dislocation.

The laterality of the gallop gait in Thoroughbred racehorses

Laterality can be observed as side biases in locomotory behaviour which, in the horse, manifest inter alia as forelimb preferences, most notably in the gallop. The current study investigated possible leading-leg preferences at the population and individual level in Thoroughbred racehorses (n = 2095) making halt-to-gallop transitions. Videos of flat races in the UK (n = 350) were studied to record, for each horse, the lead-leg preference of the initial stride into gallop from the starting stalls. Races from clockwise (C) and anti-clockwise (AC) tracks were chosen alternately at random to ensure equal representation. Course direction, horse age and sex, position relative to the inside rail and finishing position were also noted. On C courses, the left/right ratio was 1.15, which represents a significant bias to the left (z = –2.29, p = 0.022), while on AC courses it was 0.92 (z = 0.51, p = 0.610). In both course directions, there was no significant difference between winning horses that led with the left leading leg versus the right (C courses, z = –1.32, p = 0.19 and AC courses, z = –0.74, p = 0.46). Of the 2,095 horses studied 51.26% led with their L fore and 48.74% with their R, with no statistically significant difference (z = -1.16, p = 0.25). Therefore, there was no evidence of a population level motor laterality. Additionally, 22 male and 22 female horses were randomly chosen for repeated measures of leading leg preference. A laterality index was calculated for each of the 44 horses studied using the repeated measures: 22 exhibited right laterality (of which two were statistically significant) and 21 exhibited left laterality (eight being statistically significant); one horse was ambilateral. Using these data, left lateralized horses were more strongly lateralized on an individual level than the right lateralized horses (t = 2.28, p = 0.03, DF = 34) and mares were more left lateralized than males (t = 2.4, p = 0.03, DF = 19).

Erratum: Martin, J.E., et al. Welfare Risks of Repeated Application of On-Farm Killing Methods for Poultry. Animals 2018, 8, 39

The authors wish to make the following correction to their paper[...].

Proceedings of the 50th Congress of the International Society for Applied Ethology 12-15th July, 2016, Edinburgh, United Kingdom

Antibiotic (AB) resistance is a major concern worldwide. Knowledge about potential drivers of AB use and prescribing practices in the pig industry is required to address problems of mis and over use. We hypothesised that pig farmers attitudes towards the treatment and care of injured or sick pigs may influence their use of AB. Semi-structured face-to-face interviews were conducted with 30 producers who managed integrated pig units in Ireland and which supplied records to the Teagasc PigSys database. Ethical approval was obtained and pig producers were invited for interview by their Teagasc pig advisor. Consent was obtained at the time of the interview. Interviews with participants were recorded and transcribed using random numbers from 1 to 30, one per participant to ensure anonymity. Themes were then identified from the data. The importance of comfort and care in the rehabilitation of animals following injury was only expressed in relation to sows. Here the importance of straw bedding and a solid floor in ensuring recuperation from lameness/injury was mentioned by several producers (n=7). The relevance of analgesics to recovery from illness or injury was only mentioned by 2 producers who used pain relief for sows that were ‘sick after farrowing’. Injectable ABs were the most common method of treating illness or injury (n=12), followed by euthanasia (n=7). The practice of euthanising pigs was driven by economic (n=6) or humane grounds (n=9). The latter also expressed the belief that it was more humane to euthanise than to hospitalise sick or injured pigs. However, there was a general dislike for the practice of euthanasia. Many producers mentioned that it is too expensive to call a vet to treat or to euthanise sick or injured pigs. Only one producer used a vet to euthanise pigs. Several producers did not agree with the use of hospital pens (n=7) either because they believed that pigs are usually abandoned/forgotten in such pens (n=2) or because hospital pens are places where diseases are harbored and recirculated through the herd. Almost half of the producers expressed the view that medications (in-feed and/or injections) were the only solution to deal with pig health problems and to ensure good welfare. A 3rd of producers believed that the only solution to serious diseases challenges was to de-stock the herd. Low profit margins and lack of awareness of the role which husbandry and the environment have to play in the prevention of diseases as well as the role which comfort and care of pigs play in the recovery process are major barriers to reducing the reliance on medication in the pig industry

Welfare assessment of low atmospheric pressure stunning in chickens

Antibiotic (AB) resistance is a major concern worldwide. Knowledge about potential drivers of AB use and prescribing practices in the pig industry is required to address problems of mis and over use. We hypothesised that pig farmers attitudes towards the treatment and care of injured or sick pigs may influence their use of AB. Semi-structured face-to-face interviews were conducted with 30 producers who managed integrated pig units in Ireland and which supplied records to the Teagasc PigSys database. Ethical approval was obtained and pig producers were invited for interview by their Teagasc pig advisor. Consent was obtained at the time of the interview. Interviews with participants were recorded and transcribed using random numbers from 1 to 30, one per participant to ensure anonymity. Themes were then identified from the data. The importance of comfort and care in the rehabilitation of animals following injury was only expressed in relation to sows. Here the importance of straw bedding and a solid floor in ensuring recuperation from lameness/injury was mentioned by several producers (n=7). The relevance of analgesics to recovery from illness or injury was only mentioned by 2 producers who used pain relief for sows that were ‘sick after farrowing’. Injectable ABs were the most common method of treating illness or injury (n=12), followed by euthanasia (n=7). The practice of euthanising pigs was driven by economic (n=6) or humane grounds (n=9). The latter also expressed the belief that it was more humane to euthanise than to hospitalise sick or injured pigs. However, there was a general dislike for the practice of euthanasia. Many producers mentioned that it is too expensive to call a vet to treat or to euthanise sick or injured pigs. Only one producer used a vet to euthanise pigs. Several producers did not agree with the use of hospital pens (n=7) either because they believed that pigs are usually abandoned/forgotten in such pens (n=2) or because hospital pens are places where diseases are harbored and recirculated through the herd. Almost half of the producers expressed the view that medications (in-feed and/or injections) were the only solution to deal with pig health problems and to ensure good welfare. A 3rd of producers believed that the only solution to serious diseases challenges was to de-stock the herd. Low profit margins and lack of awareness of the role which husbandry and the environment have to play in the prevention of diseases as well as the role which comfort and care of pigs play in the recovery process are major barriers to reducing the reliance on medication in the pig industry