Animal Welfare A measurable science Rebecca Morrison Sustainable Swine Production System Scientist University of Minnesota, WCROC
Summary • Why is animal welfare so important? • Approaches used for studying animal welfare • Scientific measures of animal welfare
Why is animal welfare so important? • Assume that animals have rights… but that humans have a right to use domestic animals then we have a moral obligation to provide good animal welfare to the animals in our care. • Poor welfare may affect performance of animals e.g. longevity, reproduction, growth rate etc. $$
What are the appropriate standards of welfare that we should provide our animals? How do we measure welfare?
Animal welfare should be measured objectively and scientifically independent of moral considerations.
Once welfare is assessed, society or an individual should integrate biological facts with moral views and THEN sanction or condemn a animal production practice
Approaches used to study animal welfare • Feelings-based • Nature of the species • Animal choices • Functioning-based or homeostasis
Feelings-based • Defines animal welfare in terms of emotions. • Assumes animals are sentient creatures capable of pleasure and displeasure. • Emphasizes reduction in negative emotions and increases in positive emotion. • Current research establishing relationships between cognition and emotion.
Nature of the species • Animal should be raised in ‘natural’ environments and allowed to behave ‘naturally’. • “Five Freedoms” (UK Farm Animal Welfare Council, 1992) • Freedom from hunger and thirst • Freedom from discomfort • Freedom from pain, injury and disease • Freedom to express normal behavior • Freedom from fear and distress • Total ‘natural’ behavioral repertoires of animals considered.
Problems: • ‘Natural’ behavior often represents an animals attempt to survive in the wild adverse conditions which domestic animals should be spared. • Does not take into account that domestic animals have been highly selected for adaptation to “un-natural” systems. • ‘Natural’ behaviors that are not aversive should be considered.
Animal choices • Animals have functional systems which control their nutritional state, body temperature , social interactions etc. • Investigate functional systems + motivational mechanisms: identify stimuli and resources which are important to the animal.
Problems: • may vary with age, experience, time of day, confounded with familiararity and preferences may not correspond with improved welfare.
Functioning-based or homeostasis “The welfare of an individual is its state as regards to its attempt to cope with its environment” (Broom, 1986).
“State as regards to attempts to cope” refers to • (i) how much has to be done in order to cope with the environment (e.g. magnitude of the behavioral and physiological responses). • (ii) the extent to which coping attempts are succeeding (e.g. biological costs or reduced fitness).
How do we measure welfare? Measure: • the behavioral and physiological stress response of the animal to the environment • the consequent biological cost to, or reduced biological fitness for the animal.
The stress response • The central nervous system perceives a threat develops a biological response • Behavioral response • Autonomic nervous system response • Neuroendocrine nervous system response
STRESS BRAIN 1.BEHAVIOR 3.NEUROENDOCRINE SYSTEM 2.AUTONOMIC NERVOUS SYSTEM (Moberg, 2000)
Behavioral response • First line of defense to stress • The animal will avoid or remove itself from the threat e.g escaping or seeking shade if too hot. • Startle responses • Defensive of flight reactions • Pain-change in posture,a voiding use of limb and licking area, shaking head etc.
Autonomic nervous system response • The animals second line of defense • ‘flight or fight’ response (Cannon, 1929) • The autonomic response is short lived
Autonomic nervous system response HYPOTHALAMUS (Brain) CRF (corticotrophin releasing factor) Stimulates hypothalamic nuclei to transmit nerve impulses to spinal chord. These neurons conduct impulses to the adrenal medulla. ADRENAL MEDULLA (Adrenal glands) Catecholamines (e.g norepinephrine, epinephrine)
Effects on the animal • Catecholamines: • heart rate • blood pressure and flow to heart, brain and muscles • contraction of the stomach and sphincters • intestinal movements • Converts liver and muscle glycogen to glucose prepares the animal to react
Neuroendocrine response • Adrenal cortex has a central role in the neuroendocrine response to disturbance of homeostasis. • Longer term response • Effects are orientated toward metabolic changes to strengthen the animal’s ability to cope with the stressors.
Neuroendocrine response HYPOTHALAMUS (BRAIN) CRF (corticotrophin releasing factor) PITUITARY GLAND (Brain) ACTH (adrenocorticotrophic hormone) ADRENAL CORTEX (Adrenal glands) Glucocorticoids (e.g Cortisol)
Effects on the animal • Glucocorticoids: • metabolic processes • Lipolysis-mobilizes free fatty acids to glucose. • Glycolysis-mobilizes liver and muscle glycogen stores by conversion to glucose. • Gluconeogenisis-mobilizes protein by conversion to glucose. • affects reproduction, growth and metabolism (‘biological fitness’).
Assessing welfare:short-term responses • E.g handling, deliberate cruelty, tail docking, attacks by predators, emotional disturbances i.e perception of threat etc. • Behavioral measures • Orientation reaction, startle responses and defensive of flight reactions. • Behavioral indicators of pain. • Physiological measures • Heart rate • Respiratory rate and body temperature • Adrenal axis • e.g. concentration of catecholamines • (difficult to measure without sampling procedure evoking a stress response <30 sec)
Assessing welfare:long-term responses • Longer term welfare problems e.g housing system • “Biological fitness” variables • Reproductive success • Life expectancy • Weight changes • Disease
Physiological variables • Cardiovascular and blood parameters • Adrenal axis (e.g. cortisol, ACTH challenge) * Ensure that the action of collecting blood sample does not evoke an endocrine response (<2 minutes)! • Immunology (e.g. lymphocytes, disease incidence. • Behavioral measures • Lameness, redirected behavior (e.g feather pecking), stereotypies (e.g. bar biting, weaving).
Conclusion • Animal welfare should be assessed at two levels: • Measuring the behavioral and physiological stress responses of the animal to the environment. • Measuring the consequent biological cost to, or reduced biological fitness for the animal.
Serious risks to animal welfare are situations which involve long-term exposure, or frequent exposure to a stressor that results in an animal experiencing a chronic physiological stress response. + measure biological costs for short and long term stress !
Animal welfare can be measured objectively and scientifically in away which is independent of any moral considerations. A society or an individual should integrate biological facts with moral views and only THEN sanction or condemn a particular activity or animal production practice!!!!