PSXVI-18 - Heifers are from Venus, steers are from Mars: Sex differences in social behaviors in drylot housed Brahman cattle exposed to a cattle brush

Sex differences in cattle productivity and efficiency have been established, yet an empirical examination of how sex influences cattle social behavior in dry lots is absent. Our objective was to evaluate the impact of sex on the performance of social behaviors and brush use in drylot-housed Brahman yearling steers (n = 2 pens; 19 steers/pen) and heifers (n = 2 pens; 15 heifers/pen). Cattle were video recorded from 8:00 to 20:00 for 71 d, and to date, d 1 has been decoded using continuous observations. Video was decoded for social behavior for 15 minutes of every 30 minutes using continuous observations. Average bout duration (sec), total duration per day (sec), and bout frequency of allogrooming, bar licking, tongue rolling, and brush utilization were recorded for each pen. Frequency was recorded for headbutting and mounting. Data were normalized, and the differences between sexes for each behavior were evaluated with a t-test (PROC TTEST). Average bout duration, bout frequency, and total duration for allogrooming (P > 0.15), bar licking (P > 0.63), and brush use (P > 0.78) and bout frequency for brush displacement (P > 0.78) and headbutt (P > 0.76) did not differ between sexes. Heifers tended (P = 0.09) to perform more bunk displacements than steers (heifers: 94.5 ± 64.5 count/pen/d; steers: 29 ± 3 count/pen/d). Steers performed more mounts than heifers (P < 0.0001; steers: 2.5 ± 0.5 mounts/pen/d; heifers: 0 ± 0 mounts/pen/d). This preliminary evaluation suggests that sexes may differ in the prevalence and type of social behaviors performed while housed in drylots, yet inclusion of more data will confirm these early observations.