Objective: To classify life stages for companion dogs and cats by identifying clusters in age-specific disease proportions derived from medical records, providing a data-driven foundation for health examination programs. Methods: We collected 505,667 medical records from 82 veterinary facilities in South Korea between 2020 and 2023. Diagnoses were standardized using GPT-4o and S-BioBERT. Following preprocessing, data from 27 facilities yielded 222,706 canine and 39,910 feline records for the final analysis. Principal component analysis and K-means clustering (K = 4) were applied to age-specific disease proportions to identify life stages.The 10 most highest-proportion diagnoses diseases were determined for each cluster. Results: Canine life stages were classified as ≤ 1 year, 2–5 years, 6–10 years, and 11–15+ years.Feline life stages were 1–2 years, 3–8 years, 9–12 years, and 13–15+ years. In dogs, developmental diseases were common in the youngest age group, while chronic diseases were more prevalent in older groups. In cats, oral and urinary diseases were high-ranking, conjunctivitis was most common in the early stage, and chronic diseases increased with age. Conclusions and Relevance: Age-specific diagnosis patterns support four practical life stages for dogs and cats in South Korea. These boundaries can inform evidence-based preventive examination schedules, animal health policy, and pet insurance product design.

Antimicrobial resistance significantly threatens human and animal health globally, with con-siderable mortality and economic impact. This study investigated antimicrobial usage in small animal clinics in South Korea, focusing on understanding the trends in prescriptions for therapeutic and preventive purposes. Data were collected from 12 small animal clinics that were analyzed for antimicrobial prescriptions from 2018–2020. A comprehensive dataset was used, including patient signalment, clinical notes, and prescription details, and statistically analyzed using SPSS software. The results indicated that most antimicrobials (93.1%) were prescribed for the treatment of infectious diseases, with a smaller portion (6.9%) used for pre-ventive measures, such as surgery. High prescription rates were observed for the treatment of cutaneous and otological diseases, which may reflect common diseases in companion an-imals. The study highlighted a higher prescription rate for adult age groups, possibly because of the higher prevalence in those groups. Overall, this study provides valuable insights into common prescription patterns in veterinary practice and underscores the need for more strin-gent antimicrobial stewardship to curb the rise of antimicrobial resistance. This suggests that ongoing surveillance and education on appropriate antimicrobial use are crucial for optimizing treatment outcomes and minimizing the development of resistance.