Advanced use of technologies based on innovative strategies exploiting immune response to predict heat stress from milk

Heat stress is known to have a negative effect on the immune system. Moreover, heat stress is not an easy to confirm condition. Therefore, the knowledge of these effects on the immune system could be used as an indicator of heat stress. Indeed, some studies have developed technologies allowing to predict cell mediated response and humoral immune response of an animal. Unfortunately, they can hardly be used to determine the immune status in real-time. Moreover, these technologies require relatively invasive immunization and blood sampling. However, it seems possible to use immune indicator as heat stress markers. Indeed, the expression of genes coding for heat shock proteins (HSP) is known to be different during heat stress. Similar observations were also made for genes coding for cytokines and other proteins involved in inflammation and immune activation. To assess the expression of these genes, no evasive methods are required because milk somatic cells can be used for these analyzes. Cytokines can also directly be detected in milk by ELISA. With this method, it is currently possible to observe difference in cytokines concentration in milk between healthy cows and cows with subclinical mastitis. Similar results could potentially be obtained between heat stressed and non-heat stressed animals. Indeed, differences in cytokines levels are already observed in plasma. To avoid costly detection technics and allow to use potential immune biomarkers in routine, a possible alternative is the IR technologies. Indeed, infrared (IR) based technologies were shown to have a large potential. Especially mid IR (MIR) spectrometry used on raw milk as implemented in routine milk recording for dairy herd improvement has been shown to be a powerful tool beyond the estimation of major milk component as fat or protein. Many minor components and metabolites influenced by heat stress, especially in milk but also to a certain degree in blood have been found to be predictable with reasonable precision using MIR data and appropriate methods of prediction. We will present different innovative strategies how these converging developments can be combined towards advanced use of technologies based on innovative strategies exploiting immune response to predict heat stress status of dairy cows from milk.