Background: Hanwoo cattle, an indigenous Korean breed, have become economically significant due to genetic improvements and large-scale farming. As individual cow value increases, understanding their unique physiology across different life stages is crucial for optimal health management. This retrospective study aimed to investigate serum biochemistry differences among non-pregnant, pregnant, and fattening female Hanwoo cattle and establish breed-specific reference intervals (RIs) for accurate health assessment, utilizing data obtained from routine veterinary care. Methods: Blood samples were collected from female Hanwoo cattle, categorized as pregnant (n = 12), non-pregnant (n = 25), and fattening (n = 11). Eighteen serum biochemical parameters were analyzed and descriptive statistics were calculated for each group. The new RIs in different reproductive status of female Hanwoo were established using the Reference Value Advisor program. Results: Significant differences based on reproductive status were identified in blood urea nitrogen (BUN), γ-glutamyl transferase (GGT), triglyceride (TG), glucose (GLU), and creatinine (CRE) levels. BUN, GGT, and TG levels were significantly higher in fattening cattle compared to pregnant and non-pregnant cows. GLU levels increased progressively across pregnant, non-pregnant, and fattening groups, while CRE levels were significantly higher in pregnant cows. Based on values of biochemical parameters, new RI were suggested for sixteen biochemical parameters, encompassing all three reproductive stages. Conclusions: This study established new RIs for female Hanwoo cattle across nonpregnant, pregnant, and fattening stages, providing a more accurate basis for health assessment and management. These findings will contribute to improved individual cow management, supporting genetic improvement efforts, and enhancing overall herd health in female Hanwoo cattle.

ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
    Ethics statement
    Sample collection
    Serum biochemical tests
    Descriptive statistics of blood biochemical parametersof female Hanwoo
    Determination of reference intervals in serumbiochemical parameters of female Hanwoo
RESULTS
    Descriptive statistics in serum biochemistry of femaleHanwoo
    Determination of reference intervals in serumbiochemical parameters of female Hanwoo
DISCUSSION
CONCLUSION
REFERENCES

• Sung-Ho Kim(College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Korea)
• Tae-Gyun Kim(College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Korea)
• Seung-Joon Kim(College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Korea)
• Won-Jae Lee(College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Korea, Institute for Veterinary Biomedical Science, Kyungpook Natitonal University, Daegu 41566, Korea) Corresponding author
• Sang-Yup Lee(College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Korea, Bovivet, Gumi 39133, Korea)
• Saet-Byul Kim(Bovivet, Gumi 39133, Korea)
• Young-Bum Son(College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea)