Advancing estrous detection in dairy animals: challenges, innovations, and future directions

Accurate estrus detection is critical for optimizing reproductive performance and ensuring the economic sustainability of dairy operations. Traditional estrus detection methods, primarily based on visual observation of behavioral signs, face significant limitations in terms of accuracy, labor intensity, and applicability in large-scale settings. These challenges are further compounded by the high prevalence of silent ovulation and sub-estrus conditions, particularly in high-producing dairy animals, where metabolic stress and altered hormonal profiles suppress visible estrus expression. In buffaloes, less overt behavioral cues further reduce the reliability of traditional approaches. In response to these limitations, various automated estrus detection technologies have emerged, including pressure sensors, activity monitors, video surveillance, and vocalization analysis systems. While these technologies offer improved detection sensitivity, their effectiveness varies with housing conditions, environmental factors, and algorithm design. Infrared thermography (IRT) represents a promising, non-invasive alternative by detecting subtle physiological changes associated with estrus, though its practical application is influenced by coat characteristics, ambient conditions, and operator proficiency. This article critically examines the limitations of conventional methods, evaluates the advantages and constraints of current automated systems, and discusses the potential of IRT as a complementary tool. Future research directions are proposed, emphasizing the need for integrated, multivariate approaches and standardized protocols to improve detection accuracy. Advancing estrus detection technologies is essential to enhance artificial insemination success rates, improve fertility management, and ensure long-term profitability in modern dairy farming systems.