Abstract: [Objective] To systematically grasp the current status of key indicators for dairy cow breeding in large-scale pastures in Mudanjiang City,identify strengths and weaknesses in breeding management,and provide a scientific basis for improving regional dairy farming production efficiency and sustainable development levels. [Method] In April 2024,a large-scale pasture in Mudanjiang City was selected as the research subject. Core data including herd structure,reproductive performance,disease incidence, culling/mortality rates,and lactation performance were collected through on-site investigation and compared with the national and Heilongjiang Province averages for the same period. [Result] The herd structure of the pasture was relatively young but gradually stabilizing. The proportion of heifers at the beginning of the period was 29.0%,32.2% by the end. Overall reproductive performance was at a medium level domestically. Pregnancy rates for timed artificial insemination and natural estrus were 43.9% and 39.1%, respectively. The calving interval was 382 days. Disease prevention and control achieved significant results,with low incidence rates for mammary and surgical diseases. However,obstetric diseases accounted for a high proportion （50.24%）,and the incidence rate of internal medical diseases was 25.70% .The culling/mortality rate was slightly higher than the industry average. Dry cows had the highest rate （33.1%）,followed by lactating cows （26.2%）and heifers （25.1%）. Lactation performance had room for improvement. The average daily milk yield（29.3 kg）was higher than the national average,while the 305-day milk yield was 88 64 kg,milk fat percentage was 3.79%,and milk protein percentage was 3.32%,all lower than the national or Hei longjiang Province averages. [Conclusion] The pasture has foundational advantages in herd structure optimization and prevention/control of certain diseases. However,improvements are still needed in reproductive efficiency enhancement,obstetric and internal medical disease prevention/control, and lactation performance optimization.It is recommended to comprehensively enhance pasture breeding efficiency and production levels by strengthening precise reproductive management,optimizing the disease prevention and control system,scientifically adjusting feed formulations,and standardizing milking operations.

Key words: dairy cow breeding, large-scale pasture, reproductive performance, disease prevention and control, culling/mortality rate, lactation performance, Mudanjiang City