Impact of Exercise on Productivity and Behavior of Weaned Bos Indicus Cross Calves Housed in Drylots

To determine the effects of exercise on cattle productivity and behavior, two exercise regimes were evaluated against a control (n=4 pens/trt) using weaned Bos indicus cross calves (n=203) housed in drylots (16-18 head/single gender pens). Treatments were applied (3x/wk for 4 wk) in addition to routine husbandry: 1) programmatic exercise (PRO): cattle and stockperson walked in the alleyway behind their home pen for 20 min; 2) free exercise (FREE): cattle were moved into the alleyway behind their home pen, and the gate left open to provide free access to food for 60 min; and control (CON): calves left the pen only for routine husbandry. Behavioral observations were conducted on d -2 and -1 relative to treatment implementation (d 0) and on d 5, 6, 12, 13, 19, 20, 26, and 27. Instantaneous scan sampling (48 scans/d; 0800 – 1200 and 1300-1700 at 10-min intervals) was employed to create behavioral profiles for cattle (posture: stand, lie, walk; behavior: feed, drink, ruminate) in the differing treatments. Focal observations (n=40 min/d/pen) recorded the incidence of social behaviors (allogrooming, social play, agonistic interactions) and animal-environment interactions (AEI: fencepost licking, rock eating, tongue rolling, cross-suckling). Body weights were collected on d -10, 10, and 28. A Linear Mixed Model (PROC MIXED) evaluated the impact of treatment, gender, and time on cattle behavior and productivity. Steers (0.96 ± 0.03 kg/d) gained more than heifers (0.85 ± 0.03 P=0.04), and FREE (0.99 ± 0.04) tended (P=0.06) to have higher ADG (kg/d) than PRO (0.86 ± 0.04) or CON (0.85 ± 0.04). FREE and PRO tended to ruminate more than CON (P=0.08). Allogrooming (P=0.05), lying (P=0.001), AEI (P<0.01), and rumination (P<0.01) increased over time. Agonistic interactions increased over time (P=0.003), and heifers (0.54 ± 0.07) tended (P=0.09) to engage in more agonistic interactions (proportion of pen/10-min) than steers (0.35 ± 0.07). Anecdotally, PRO cattle became tired after 7 min of walking; shorter programmed exercise regimes may yield production benefits more similar to FREE. While FREE positively influenced productivity, exercise did not alter behaviors. Comfort-related behaviors increased (e.g., lying, rumination) over the evaluation period suggesting that calves became acclimated to the environment. However, increases in AEI and agonistic behaviors over the evaluation period suggest that cattle may benefit from periods of increased activity and mental stimulation. Moderate exercise may yield production benefits, does not reduce the performance of production-critical behaviors, and may be beneficial to cattle health and welfare.