Individual Variation in Salt Block Licking and Its Relationship With the Social Hierarchy of Resource Access in Beef Cows: A Case Study

This study aimed to evaluate the relationship between the licking time of salt block (LT) and the social hierarchy (SH) of resource access of cows. LT and SH were determined for 20 days using 19 Japanese Black beef cows under group-feeding, and then classified into three rank groups (low, medium, and high) based on their SH ranking. The average LT showed significant variations among individuals (p < 0.05), ranging from 17.9 to 1124.3 s/day. In the GLM analysis, there were no significant effects of SH, parity, or body weight on LT (p > 0.10). Although there was no correlation between the LT and the SH (p > 0.1, ρ = -0.08), and LT was not consistently associated with the social hierarchy, the low SH group tended to have greater individual variation in LT than high SH group (p = 0.053). Lower SH cows may experience either enhanced or reduced motivation for salt block licking due to behavioral interruption by higher SH cows, which could reduce their opportunities to display a medium LT.