Milk phenomics: leveraging biological bonds with blood and infrared technologies for evaluating animal nutritional and health status

Over recent decades, there was a substantial evolution in the productive management of dairy animals worldwide with a consequent boost in individual milk yield. This evolution positioned the milk production as the central metabolic priority around which all other physiological functions are coordinated and partially minimised. This shift underscores the crucial role of effectively managing stressful phases in intensive dairy farming systems, also highlighting the resilience exhibited by the animals. Indeed, monitoring the nutritional and health status becomes paramount, aiming for an early detection of (sub)clinical health impairments. Given the mammary gland’s centrality in high-yielding dairy breeds, it’s unsurprising that the milk matrix provides insights about udder itself but also systemic metabolic function. The emerging field of milk phenomics explores links between milk components and animal health, holding great promise for studying dairy cow resilience. The use of infrared spectroscopy on milk to predict indicators and complex traits at the herd level is a promising approach. In the dairy sector, the available infrared instruments mainly implement the Fourier transform infrared (FTIR) spectroscopy. This method is widely employed in milk recording schemes worldwide for animal monitoring and breeding purposes. In addition, visible and near-infrared (NIR) spectroscopy is increasingly integrated into milking systems for daily on-farm monitoring of milk quality and animals’ physiological status. This review examines the topic of milk phenomics together with potential and challenges of infrared spectroscopy to predict indicators and complex traits related to health and nutritional disorders exploiting the biological bonds that exist between milk and blood in dairy animals.