Using aversion learning techniques to assess the mental state, suffering, and welfare of farm animals

The extent that handling farm animals causes them to suffer is a central concern when assessing their welfare. “Suffering” is a mental state, resulting from different emotions, such as fear, pain, or boredom, which have different causes and effects on the animal’s behavior and physiology. What is common is that they are aversive; animals will […]

Stunning pigs with different gas mixtures: aversion in pigs

The objective of this study was to assess the aversion to exposure of 90% argon, 70% N2/30% CO2 and 85% N2/15% CO2 by volume in atmospheric air in 24 halothane-free slaughter-weight pigs using aversion learning techniques and behavioural studies in an experimental slaughterhouse. Pigs were subjected to the treatments individually during 2 separate trials of […]

The aversion of broiler chickens to concurrent vibrational and thermal stressors

The requirement for assessing the effects of multiple concurrent stressors in improving the welfare of broiler chickens during transport has not been widely recognised. A discrete-choice technique was used to investigate the aversion of broiler chickens to concurrent vibrational and thermal transport stressors. In experiment 1, 12 female broiler chickens, aged 42+/-3 days were studied […]

Applying chemical stimuli on feathers to reduce feather pecking in laying hens

Recent studies have shown that spraying a distasteful substance (quinine) on a bird’s feather cover reduced short-term feather pecking. The present experiment evaluated if other substances offer similar or better protection against feather pecking. One hundred and twenty birds were divided into 12 groups of 10 birds each. Over a period of 10 days the […]

Assessing the relative aversiveness of two stimuli: single sheep in the arena test

In the test described here, sheep are exposed to a situation of conflict between the motivation to approach other sheep and the motivation to avoid a human handler. The distance that the test sheep keep from the handler is a reflection of the relative aversiveness of this handler to the sheep. The test itself requires […]

Conditioned approach-avoidance responses to humans: the ability of pigs to associate feeding and aversive social experiences in the presence of humans with humans

Since there is a number of common industry husbandry procedures conducted by stockpersons that may have rewarding or aversive elements for pigs, pigs may learn to associate these rewarding or aversive elements of a procedure with the handler conducting the procedure. Therefore, because of this second-order conditioning, changes in the behavioural response of pigs to […]

Gas killing of rats: the effect of supplemental oxygen on aversion to carbon dioxide

High concentrations of carbon dioxide (CO2), used for killing laboratory rodents, are known to be more strongly aversive to rats than sweet food items are attractive. This study investigated whether the maintenance of a high oxygen (O2) concentration, using a gas mixture of 70% CO2 and 30% O2, would reduce aversion to CO2 during a […]

A continuous-choice assessment of the domestic fowl’s aversion to concurrent transport stressors

Characterisation of the effect of transport on the welfare of fowl requires common currency methods that can compare the effects of diverse stressors using the same unit of measure. Aversion of broiler chickens (42 ± 1 days old) to vibrational and thermal stressors was investigated in a continuous free-choice procedure. Each choice-chamber had four compartments, […]

Welfare implications of the Gas Stunning of Pigs 2. Stress of Induction of Anaesthesia.

The severity of respiratory distress occurring prior to loss of posture during exposure to: 20, 30, 40, 50, 60, 70, 80 or 90 per cent carbon dioxide in air; 2 or 5 per cent residual oxygen in argon; 30 per cent carbon dioxide in argon with either 2 or 5 per cent residual oxygen; or […]

Aversion of chickens to various lethal gas mixtures

In the event of a notifiable disease outbreak, poultry may need to be culled in situ. This should be performed swiftly and humanely to prevent further spread of the pathogen while preserving the welfare of the animals prior to death. Here, we examined the aversion of broiler chicks (Gallus domesticus) to three lethal gas mixtures […]