N.G. Gregory

Differential effects of increased stocking density, mediated by increased flock size, on feather pecking and aggression in laying hens

Six flocks of laying hens were housed in percheries at each of four stocking densities (6, 14, 22 or 30 birds m−2) from 14 to 30 weeks of age. Stocking density was manipulated by changes in flock size (72, 168, 264 or 368 birds) within percheries of the same floor and height dimensions. The pecking behaviour of birds was observed directly at 15, 22 and 30 weeks of age, and corrected for the number of birds in view. Egg production was recorded at 23 and 27 weeks of age, and plumage condition was scored at 30 weeks of age. At 23 weeks of age, egg production was greater at 6 birds m−2 than at other stocking densities. The plumage condition of the birds was best at 6 birds m−2 and worsened with increased flock size and stocking density. The behavioural observations suggested that this was due to an increase in mild feather pecking with increased flock size and stocking density. Mild feather pecking increased with bird age and was most frequently observed on the perchery floor although, at higher flock sizes and stocking densities, it also occurred on the perches. Severe feather pecking was infrequent, especially at the lower flock sizes and stocking densities, but was most likely to occur near the nest boxes. Vent pecking was extremely rare. Aggressive pecking was most common in the smaller flocks at the lowest stocking densities, possibly because these birds attempted to form social hierarchies. Birds in the larger flocks at higher densities appeared to adopt non-social, non-aggressive behavioural strategies.

Animal welfare at markets and during transport and slaughter

This review highlights some recent developments in our understanding of stress and physical injuries that occur before and during transport to slaughter, during handling at livestock markets, and at the time animals are put-up for slaughter within abattoirs. Stress in pigs during transfer to the stunning point within the abattoir has important effects on meat quality, and there is growing evidence that strenuous exercise or CO(2) stunning can contribute to oxidative rancidity in pigs, poultry and fish. In the EU, putting cattle through a crush in order to check that their eartag numbers correspond to their passport numbers is imposing additional stress, and there are reports that it is leading to greater hide contamination with Escherichia coli O157. Recent developments in stunning and slaughter include a better understanding of the causes of variation in captive bolt gun performance, the effectiveness of poll instead of frontal shooting in water buffalo, the prevalence of false aneurysms in carotid arteries during shechita and halal slaughter, and the stress effects of CO(2) stunning in fish. Stunning pigs with 90% CO(2) leads to less PSE meat than 80% CO(2). There have been concerns about the physical activity that cattle show following electrical stunning with an electrically induced cardiac arrest, and with electrical stunning using DC waveforms in broiler chickens. There is also growing concern about the hygiene problems that exist in wet markets, where animals are slaughtered alongside meat that is on display to customers.

Bone structure and breaking strength in laying hens housed in different husbandry systems

1. Bone structure and breaking strength were measured in hens that had been housed throughout a laying year in battery cages or in Perchery, Naturel or Litter and Wire husbandry systems. 2. Battery caged hens had the poorest bones, as assessed by measurements of cancellous bone volume, radiographic density, cortical thickness and three-point breaking strength. 3. Humeri from birds in the Litter and Wire system were less dense radiographically and weaker than those from Perchery or Naturel birds but leg bone characteristics were similar with these three systems. 4. There were no differences in bone characteristics between birds in Perchery and Naturel systems. 5. There were strong correlations between radiographic densities and strengths of contralateral humeri and tibiae over all husbandry systems. Humerus structural and strength characteristics may be the best criteria of osteoporosis in hens. 6. It is concluded that the extent of movement allowed by different husbandry systems affects structural bone loss and bone strength in laying hens. 7. It is further concluded that the breaking strength of a hens bone is closely related to morphometric measures and radiographic density of its structural components.

Recent concerns about stunning and slaughter

This review summarises information that is relevant to concerns that have recently been expressed about stunning and slaughter. It is known that captive bolt stunning can result in brain material passing to the lungs via the jugular veins. If future studies show that BSE prions pass beyond the lungs to the edible carcass, there will be a move away from captive bolt stunning in large cattle towards electrical stunning. Greater use of electrical stunning in large cattle will increase the importance of blood splash in the beef industry. The theoretical causes of blood splash are reviewed to improve our understanding of this problem. In some situations it can be due to excessive venous pressure causing rupture of a capillary bed some distance from the source of the pressure rise, but it is not known whether this applies to electrical stunning. Gas stunning is replacing electrical stunning for poultry because it can reduce blood spots, which is a similar condition to blood splash. Several gas stunning methods are now being used, but it is not clear which of these is the most humane. Anoxic stunning leads to carcass convulsions and this causes more carcass damage. In fish, recent developments in electrical stunning are showing promise in overcoming problems with carcass damage. It is recommended that rock lobsters should be chilled or frozen before butchery, to ensure a humane death.

Physiology and behaviour of animal suffering.

Foreword. Preface. 1 Introduction. 1.1 What Is Suffering?. 1.2 Why Worry about Suffering?. 1.3 When Can We Stop Worrying about Suffering?. 1.4 Recognising Suffering in Animals. 1.5 Can Animals Go Mad?. 1.6 What Constitutes Animal Suffering?. 1.7 Conclusions. 2 Stress. 2.1 Stress Physiology. 2.2 Stress--related Disorders. 2.3 Restraint Stress. 2.4 Stress--induced Analgesia. 2.5 Stress--induced Seizures and Fits. 3 Anxiety and Fear. 3.1 Introduction. 3.2 Anxiety. 3.3 Experimental Models. 3.4 Fear. 3.5 Fright. 3.6 Phobias. 3.7 Panic. 3.8 The Role of the Amygdala. 3.9 Losing Ones Mother. 4 Emotional Numbness and Deprivation. 4.1 Anhedonia. 4.2 Depression. 4.3 Social isolation in the Newborn. 4.4 Sensory Deprivation in Early Life. 4.5 Sensory Deprivation in Later Life. 4.6 Social isolation and barren environments. 4.7 Stereotypies and neurotic behaviours. 4.8 Learned Helplessness. 4.9 Post--traumatic Stress Disorder. 4.10 Sleep Disorders. 4.11 Weaning. 4.12 Physiology of Emotions. 5 Aggression, Overcrowding and Discomfort. 5.1 Aggression. 5.2 Overcrowding and Confinement. 5.3 Discomfort. 6 Exercise. 6.1 Overexertion. 6.2 Endurance Riding. 6.3 Horse--racing Injuries. 6.4 Greyhound Racing Injuries. 6.5 Migration. 7 Cold. 7.1 Cold Discomfort and Pain. 7.2 Skin Freezing and Chilblains. 7.3 Hypothermia. 7.4 Sensitivity to Cold. 7.5 Hypothermia and Cold Survival. 7.6 Cold in Combination with Starvation. 7.7 Cold--induced Analgesia. 8 Heat and Burns. 8.1 Heat Stress. 8.2 Heat Intolerance. 8.3 Some Species Differences. 8.4 Pain. 8.5 Burns and Scalds. 9 Thirst and Hunger. 9.1 Thirst and Dehydration. 9.2 Overhydration. 9.3 Osmotic Stress. 9.4 Hunger. 9.5 Underfeeding. 9.6 Emaciation. 9.7 Inappropriate Diets. 9.8 Forced Moulting. 9.9 Force--feeding and Overeating. 10 Pain. 10.1 The Value of Pain. 10.2 Pain Associated with Trauma. 10.3 Ways in Which Animals Express Pain. 10.4 Pain Pathways and Consciousness. 10.5 Cortical Regions. 10.6 Applied Neurology of Pain. 10.7 Pain in a Given Context. 11 Trauma. 11.1 Injuries in Selected Body Regions and Tissues. 11.2 Some Common Causes of Injury. 11.3 Intended or Avoidable Causes of Trauma. 11.4 Types of Injury. 12 Sickness and Disease. 12.1 Is Suffering an Inevitable Consequence of Being Ill?. 12.2 Do the Behaviours Expressed During Sickness Serve a Purpose?. 12.3 Cytokines and Sickness Behaviours. 12.4 Cancer. 12.5 Stress and Immune Function. 12.6 Corticosteroid Therapy. 12.7 Anaemia. 12.8 Hazards of Improving Disease Control. 12.9 Diseases Used in Controlling Pests. 13 Digestive System. 13.1 Nausea. 13.2 Vomiting and Retching. 13.3 Gut Pain. 13.4 Diarrhoea. 13.5 Gut Injuries. 13.6 Stress and the Gut. 13.7 Gastro--intestinal Ulcers. 14 Poisoning. 14.1 Wartime Poisons. 14.2 Environmental Toxicants. 14.3 Vertebrate Pesticides. 15 Respiratory System. 15.1 Asphyxia. 15.2 Breathlessness. 15.3 Carbon Dioxide Inhalation. 15.4 Drowning. 15.5 Pulmonary Oedema. 15.6 Hypoxia. 15.7 Altitude Sickness. 15.8 Decompression. 15.9 Collapse of the Lung and Pneumothorax. 15.10 Asthma and Allergies. 15.11 Ammonia. 15.12 Signs of Respiratory Distress. 15.13 Agonal Gasping. 16 Dying. 16.1 Euthanasia. 16.2 Decapitation. 16.3 Religious Slaughter. 16.4 Death from Brain Injury. 16.5 Recognising Insensibility and Brain Death. References. Abbreviations. Index.

Preslaughter handling, stunning and slaughter.

This paper reviews some of the recent developments in scientific research into preslaughter handling, transport, stunning and slaughter. Particular emphasis has been placed on work published within the past 2 years, and on the welfare and meat quality aspects of the subject.

Effect of slaughter on the spontaneous and evoked activity of the brain

The principal blood vessels in the neck which are severed at slaughter in commercial poultry processing plants are described. Mechanical slaughtering methods often severed the spinal cord without cutting the carotid arteries. The manual method of slaughter cut one carotid artery plus one jugular vein. The effects of 9 different slaughtering methods on spontaneous and evoked electrical activity in the brain were examined in anaesthetised chickens and ducks. Severing the spinal cord without cutting the carotid arteries was found to result in death from asphyxia, and cutting one carotid artery plus one jugular vein was one of the slowest methods of killing the birds. Inducing a cardiac arrest at electrical stunning was the quickest method of inducing death. Spontaneous activity in the brain was lost before visual evoked activity. The times before loss of spontaneous activity varied between 23 and 233 s according to the method of slaughter and loss of evoked activity ranged between 90 and 349 s after slaughter.

Effect of stunning on spontaneous physical activity and evoked activity in the brain.

1. The effect of stunning current on the time to recovery of physical activity, and on somatosensory evoked potentials (SEPs) in the brain, was examined in broiler chickens. 2. Increasing stunning current was associated with an increase in the time to recovery of tension in the neck muscles and with an increase in the incidence of loss of SEPs. 3. Currents greater than 105 mA per bird provided 52 s or more of apparent insensibility; currents greater than 120 mA were associated with absence of SEPs following the stun.

Animal welfare and meat production.

* Animal Welfare and the Meat Market * Animal Welfare in Developing Countries * Genetics and Animal Welfare * Cattle * Sheep * Pigs * Poultry and Rabbits * Aquaculture * Other species * Livestock Presentation and Welfare before Slaughter * Stunning and Slaughter * Meat Quality * Implementing Effective Animal Welfare Auditing Programs by Temple Gandin * The Future.

Depth of concussion in cattle shot by penetrating captive bolt.

The prevalence of shallow depth of concussion following captive bolt shooting was assessed in 1608 cattle at an abattoir. Depth of concussion was determined in each animal from physical collapse, presence or absence of corneal reflex, normal rhythmic breathing, eyeball rotation, and whether the animal was re-shot. The presence of nystagmus and the absence of tongue protrusion were also monitored as potential indicators of a shallow depth of concussion, and simultaneous noise measurements assessed whether loudness of gun discharge was linked to concussion depth. The prevalence of a shallow depth of concussion was 8% for all cattle and 15% for young bulls. Nystagmus was associated with other indicators of a shallow depth of concussion. Absence of tongue protrusion was not associated with depth of concussion, but could serve as a useful indicator of jaw relaxation and insensibility following exsanguination. Soft-sounding shots (⩽111dB) when using 4.5 gr cartridges were associated with shallow depth of concussion.