title: Exploration of the hypothalamic-pituitary-adrenal function as a tool to evaluate animal welfare.
abstract: Measuring HPA axis activity is the standard approach to the study of stress and welfare in farm animals. Although the reference technique is the use of blood plasma to measure glucocorticoid hormones (cortisol or corticosterone), several alternative methods such as the measurement of corticosteroids in saliva, urine or faeces have been developed to overcome the stress induced by blood sampling itself. In chronic stress situations, as is frequently the case in studies about farm animal welfare, hormonal secretions are usually unchanged but dynamic testing allows the demonstration of functional changes at several levels of the system, including the sensitization of the adrenal cortex to ACTH and the resistance of the axis to feedback inhibition by corticosteroids (dexamethasone suppression test). Beyond these procedural aspects, the main pitfall in the use of HPA axis activity is in the interpretation of experimental data. The large variability of the system has to be taken into consideration, since corticosteroid hormone secretion is usually pulsatile, follows diurnal and seasonal rhythms, is influenced by feed intake and environmental factors such as temperature and humidity, age and physiological state, just to cite the main sources of variation. The corresponding changes reflect the important role of glucocorticoid hormones in a number of basic physiological processes such as energy metabolism and central nervous system functioning. Furthermore, large differences have been found across species, breeds and individuals, which reflect the contribution of genetic factors and environmental influences, especially during development, in HPA axis functioning. Usually, these results will be integrated with data from behavioral observation, production and pathology records in a comprehensive approach of farm animal welfare.
authors.affiliation: Neurogenetics and Stress, UMR1243 INRA, Université Victor Segalen Bordeaux 2, 33076 Bordeaux, France. Pierre.Mormede@bordeaux.inra.fr
authors.forename: Pierre
authors.initials: P
authors.lastname: Mormède
authors.forename: Stéphane
authors.initials: S
authors.lastname: Andanson
authors.forename: Benoit
authors.initials: B
authors.lastname: Aupérin
authors.forename: Bonne
authors.initials: B
authors.lastname: Beerda
authors.forename: Daniel
authors.initials: D
authors.lastname: Guémené
authors.forename: Jens
authors.initials: J
authors.lastname: Malmkvist
authors.forename: Xavier
authors.initials: X
authors.lastname: Manteca
authors.forename: Gerhard
authors.initials: G
authors.lastname: Manteuffel
authors.forename: Patrick
authors.initials: P
authors.lastname: Prunet
authors.forename: Cornelis G
authors.initials: CG
authors.lastname: van Reenen
authors.forename: Sabine
authors.initials: S
authors.lastname: Richard
authors.forename: Isabelle
authors.initials: I
authors.lastname: Veissier
mesh_terms: D000827:Animal Welfare; D000818:Animals; D000829:Animals, Domestic / Q000145:classification / Q000502:physiology*; D005069:Evaluation Studies as Topic; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D010913:Pituitary-Adrenal System / Q000502:physiology*