The application of Veterinary Ultrasound technology in the diagnosis and management of cow reproduction is an innovation in China's modern dairy farming industry. With the rapid expansion of dairy farming scale, the milk production of cows continues to increase, and the pressure of cow breeding work and the urgency of overall level improvement have also been increasingly valued by people.

Due to climate factors such as heat stress in the south, typically only a small number of cattle participate in breeding on large-scale ranches from June to November each year. This requires us to conduct early pregnancy diagnosis as soon as possible after cow breeding, and portable and efficient veterinary ultrasound plays an important role.

Research has shown that the compliance or accuracy of animal B-ultrasound pregnancy testing can reach 100% as the breeding days increase to 35 days. Therefore, this study utilized veterinary ultrasound for the application and effectiveness analysis of reproductive diagnosis in large-scale ranches, aiming to explore the performance and improvement measures of cow reproductive function under heat stress conditions in the south.

The use of veterinary ultrasound for early pregnancy diagnosis and strengthening reproductive program management has two purposes: (1) to understand the pregnancy status of breeding as early as possible and monitor the progress of breeding work in a timely manner. For pregnant cows. We should know its general situation, which cannot be used as a basis for determining the pregnancy at this time. (2) Accurately identify empty cows and know the proportion and individuals of empty cows as early as possible.