Preferences for overhead sprinklers by naïve beef steers: Test of two nozzle types

Sprinklers effectively reduce heat load in cattle. In some studies, however, cattle readily use sprinklers, while others find that they either avoid or show no preference for it. These studies differ in many ways including previous experience of the animals and the amount of water delivered. Our objective was to test preferences for the amount of water delivered using animals that had no previous experience with man-made water cooling. We used a sprinkler system with nozzles mounted over the feed bunk that intermittently spray (on for 7 out of every 20 min/24 h in this experiment) the animals’ backs while they fed. Steers (366 ± 50 kg) were housed in groups of four (n = 8 groups; four groups tested simultaneously) and provided two unshaded feed bunks in adjacent, connected pens with and without sprinklers in summer. Each group was tested with two nozzle types that delivered different amounts of water (1.3 L/min vs. unsprinkled control; 2.6 L/min vs. unsprinkled control). To ensure steers were making an informed choice, they were first fed solely from each feed bunk (with and without sprinklers) for 1 day each, for each nozzle type. Preference was then evaluated for 3 days, during which time the animals were fed ad libitum from both feed bunks. Behavior was recorded with 10-min instantaneous focal sampling from 13:00 to 19:00 h each day (air temperature was 32.5 ± 4.8 °C during this time [mean ± SD]). Steers spent more than 70% of their total time, both standing and lying, in the side of the pen that contained sprinklers (P ≤ 0.009) in both nozzle comparisons. Steers spent more time within 1.6 m of the sprayed area in the 1.3 L/min treatment compared to the unsprinkled control bunk (63% of 6 h, P = 0.053), and this preference became more marked as ambient heat load increased. In contrast, cattle showed no overall preference for the area around the feed bunk fitted with 2.6 L/min nozzles (57% of 6 h in sprinkled bunk compared to unsprinkled bunk, P = 0.234), and only preferred this area during warmer weather and when the water was actively being sprayed. These results indicate that naïve cattle will readily choose to use overhead sprinklers, particularly in warmer conditions and when lower amounts of water are delivered. Further work is required to determine the amount of water that cattle will discriminate between and how this influences their physiological response to heat load.