Rare Earth Elements (REEs) in veterinary medicine: practical applications and tissue distribution in terrestrial vertebrate animals.

Rare earth elements (REEs) have shown promising potential in veterinary medicine, particularly as feed additives and diagnostic and therapeutic tools. Moreover, the increasing industrial use of REEs has raised concerns about their potential environmental contamination and bioaccumulation in animal tissues. While numerous studies have focused on the distribution of REEs in marine and freshwater ecosystems, information regarding their presence in terrestrial environments remains fragmented. This narrative review aims to describe the practical applications of REEs in veterinary medicine, with a specific focus on studies evaluating the potential accumulation of these elements in the tissues of terrestrial vertebrate animals. Additionally, the review addresses research on the intentional residual presence of REEs and in-field studies evaluating the contamination burden from REE exposure in domestic and wild animals. In conclusion, this review identifies critical scientific gaps and provides future research directions to advance understanding of the long-term effects, mechanisms of action, and environmental impacts of REEs in veterinary practices.