Figure 1.

Depiction of the use of an epigenetic livestock clock in animal breeding. The black line represents the epigenetic clock established from the training animals (black dots). Animals with a younger biological age (green) compared with those that are estimated to have an older biological age (red) than their true chronological age. Those in blue have an estimated biological age that does not deviate from their true chronological age. In (A), the livestock epigenetic clock is used for early-in-life selection of animals, whereby those estimated to have a younger biological age may be selected with assumption of improved longevity, or the “biological age” could be included in genetic evaluation, to adjust an individual’s performance. In (B), the livestock epigenetic clock is used to measure historical stress, for health and welfare monitoring of animals. .