Abstract
This study investigated the seroprevalence of bovine leukemia virus (BLV) in beef breeding cattle in Ibaraki, revealing a seroprevalence of 43.0% with a bimodal distribution in farms classified as either BLV-negative or very-highly infected. These results underscore the need to implement appropriate strategies for very-highly infected farms. In particular, determining the culling prioritization of cattle is absolutely necessary. It was revealed that effective control in very-highly infected farms is difficult based on types of operation or herd size. On the other hand, high-transmission-risk cattle were widely distributed across entire Ibaraki and were significantly more prevalent in very-highly infected farms. These findings suggest that the transmission risk classification is a potentially effective strategy for culling prioritization under the current circumstances in Ibaraki.