The steep increase in individual milk yield of modern dairy cows has unfortunately been accompanied by a decrease in cows’ lifespan. Nonetheless, greater productive longevity can improve the profitability of a dairy herd by lower culling rates and a lower need for replacement heifers, a higher overall milk production, an improved public opinion about dairy cow welfare and a decrease of the environmental footprint of dairy herds. The major gap to realize this is the lack of an accurate biomarker that enables the direct selection of young calves with a long productive lifespan. In the present research proposal, we will search for an innovative early life biomarker that is correlated with productive longevity in high-yielding dairy cows. The present proposal has three main objectives: 1) to determine if, and at what stage in life, telomere length is correlated with productive longevity in dairy cattle (WP1); 2) to identify metabolites and metabolic pathways that are associated with productive longevity (WP2); 3) to further unravel some basic characteristics in relation to the physiology of ageing, of the biomarkers proposed (WP3+4). The ultimate goal is to set up a high-throughput method that is applicable for a large sample size at a reasonable cost to be ready for commercialization.