Breeding for Metabolic Robustness and Longevity in Dairy Cows

The relevance of longevity among the traits in dairy cattle for which genetic improvements are desirable is undisputed as welfare and economic considerations underline this importance. Longevity, again as seen in the context of many relevant traits, is a difficult trait since early selection decisions are desired but the precise longevity of an individual animal can only be derived after its death and thus at a later stage in the trajectory of time. Several approaches for modelling of longevity exist, among them are survival analysis and random regression models that by definition are highly suitable to model effects along the trajectory of time. In a broader sense, the concept of longevity has to be extended to robustness and resilience. This latter term has recently gained in popularity as in general definitions are sought that reflect an individual’s ability to cope with stressors, be it individual diseases or relevant effects such as hygiene, heat stress, and energy balance. The genetic ability for a long productive life of an individual in a dairy cattle population is only inadequately described by simple measurements of longevity. In this context, cow training sets with precise recordings of diseases and other relevant effects as well as new biomarkers giving more insight into the physiological status of a cow are needed. In future dairy cattle breeding, approaches that jointly combine information on longevity, health, and resilience will be the method of choice.