Reproduction as a key component of animal welfare: Conceptual foundations for sustainable livestock farming

Modern global livestock farming is undergoing transformative changes driven by the need to implement the principles of sustainable development, ethical farming and high standards of animal welfare. For a long time, in animal science and practice, reproductive performance has been assessed primarily through the prism of economic efficiency and production intensification, whilst its significance as an indicator of the biological, physiological and psycho-emotional state of animals has remained insufficiently explored. The aim of the study was to provide a theoretical justification and to develop a comprehensive conceptual model of reproduction as a key component of farm animal welfare to ensure the long-term sustainability of the livestock sector. The methodology of the study was based on the application of systemic-structural analysis, scientific generalisation, comparison and conceptual modelling of the results of contemporary fundamental and applied research indexed in the scientometric databases Scopus and Web of Science. As a result of the study, the neuroendocrine and physiological mechanisms of reproductive function suppression under the influence of technological and environmental stress, caused by the activation of the hypothalamic-pituitary-adrenal axis and elevated cortisol levels, were detailed. Causal links have been established between poor housing conditions, chronic stress and delayed recovery of the oestrous cycle following parturition. The importance of the expression of natural reproductive and maternal behaviour as a key indicator of the formation of a positive emotional state in animals within the context of the modern Five Domains model has been substantiated. A conceptual framework has been developed that integrates reproductive health parameters, behavioural responses and technological factors into a unified system for assessing animal welfare. The practical significance of the results lies in the development of scientifically grounded approaches to adapting technological processes in animal husbandry, enabling the effective combination of a high level of animal welfare with their reproductive capacity and the long-term economic efficiency of farming