What is the function of an ear tag in cattle management?

Ear tags serve a critical role in cattle management primarily by providing a means of identification for individual animals. Each tag carries a unique number or code that allows farmers and ranchers to track various aspects of an animal's life, such as its lineage, health records, and breeding history. This identification is essential for managing herds effectively, as it facilitates the organization of data necessary for monitoring growth rates, vaccination schedules, and overall herd health.

In the context of the other choices, while nutrition information, medicine administration, and health monitoring are all important aspects of cattle management, these functions are achieved through different means. For example, nutrition would typically be tracked through feeding records, medicine is usually administered via injections or oral doses without the need for a tag, and health issues are monitored through veterinary examinations and observations on the farm, not solely through a tag. Therefore, the primary function of an ear tag is indeed to identify the calf, which plays a foundational role in effective cattle management practices.