Differences in the behavior of the crossbred steers of different sire lines of Japanese Black cattle

We determined differences in the behavior of the progeny of two major sire lines of Japanese Black cattle by recording the behavior of 35 and 70 half-sib steers of sires from fast (FG) and slow (SG) growing lines, respectively. Two sire lines of steers were mixed and allocated to nine pens with 11–12 animals per pen. The proportion of steers lying was significantly (P < 0.001) higher in the SG line (43.4 ± 5.7% compared to 40.3 ± 6.0%). The proportion of time spent eating concentrate feed (FG: 12.1 ± 2.3%; SG: 11.4 ± 2.1%), drinking (FG: 0.8 ± 1.1%; SG: 0.4 ± 0.6%), licking the feed trough (FG: 0.4 ± 0.6%; SG: 0.2 ± 0.4%) and performing tongue-playing (FG: 3.1 ± 4.6%; SG: 1.0 ± 1.9%) was significantly higher in FG, whereas the proportion of time spent resting (FG: 41.5 ± 12.8%; SG: 43.7 ± 10.9%) and performing self-licking (FG: 1.7 ± 1.4%; SG: 2.1 ± 1.3%) was higher in SG (all P < 0.05). These results show progeny of the FG sire engaged in more active behaviors compared to the progeny of the SG sire line.