Monitor individual health and improve breeding success in the crested ibis ( <i>Nipponia nippon</i> )

Abstract Accelerating biodiversity loss highlights the urgent need for effective conservation measures, and the recovery of crested ibis (Nipponia nippon) can serve as a useful model. We analyzed a 17-year dataset from a captive population at Dongzhai National Nature Reserve, China, comprising 5,893 body mass records from 257 individuals across 9 generations. Using quantitative genetic tools (Animal Model), we found that body mass exhibited significant heritability (h2 = 0.54). As for growth curve parameters, growth time-scale parameter a (h2 = 0.30) and growth-rate coefficient b (h2 = 0.23) were also significantly heritable, while the heritability of potential maximum weight M was relatively low (h2 = 0.05). Estimated breeding values for body mass showed an increasing intergenerational trend, though this did not differ significantly from expectations under genetic drift. Importantly, the heritability of these traits enables the establishment of a personalized expected growth trend based on parents and healthy siblings. The comparison revealed that healthy offspring closely followed parental growth trajectories, whereas unhealthy individuals showed observable deviations. Considering the multiple breeding attempts throughout the lifetime of this long-lived species, cumulative historical data could help refine these family-specific baselines, providing a practical reference for monitoring individual health and allowing timely veterinary interventions.