The article discusses the complexities of horse breeding, emphasizing that both linebreeding and inbreeding increase homozygosity and reduce genetic diversity, concentrating not only desirable traits but also hidden genetic vulnerabilities. While linebreeding is often seen as a strategic way to reinforce excellence by repeating notable ancestors in a pedigree, biologically it functions similarly to inbreeding, quietly accumulating latent weaknesses that may manifest over generations. Modern reproductive technologies have accelerated the spread of genetics from a few influential sires, further narrowing genetic diversity and resilience within breeds.

The article highlights four major categories of genetic vulnerabilities common across breeds: connective tissue disorders, muscle enzyme defects, immune system weaknesses, and sensitive temperaments. Despite pedigree culture celebrating repeated ancestors as a mark of quality, this repetition actually signals increased biological risk. Genomic tools like COI and ROH reveal these risks more clearly than traditional pedigree analysis. Ultimately, the article calls for a shift away from glorifying pedigrees toward prioritizing true genetic diversity to safeguard the long-term health, soundness, and integrity of horses, emphasizing that breeding decisions should be guided by the living horse’s well-being rather than commercial or aesthetic interests.