Water spray cooling during handling of feedlot cattle

摘要

Activities involved in receiving or working (e.g., sorting, dehorning, castration, weighing, implanting, etc.) of feedlot cattle cause an increase in body temperature. During hot weather the increased body temperature may disrupt normal behaviors including eating, which can be especially detrimental to the well-being and performance of the animals. Sprinkle cooling of animals has been successfully employed within the pen; however, added moisture to the pens' surface increases odor generation from the pen. A study was conducted to investigate the effectiveness of a single instance of wetting an animal within the working facility instead of in the pen, which could potentially provide extra evaporative cooling to offset the added heat produced by activity. Sixty-four cross-bred heifers were assigned to one of eight pens on the basis of weight. On four separate occasions during hot conditions (average temperature 28.2pl1.9pC, 29.1pl2.0pC, 28.9pl3.0pC, and 26.8pl1.6pC; with the temperature ranging from 22.6 to 32.5pC during the trials), the heifers were moved from their pens to and from the working facility (a building with a scale and squeeze chute located 160-200 m away). While in the squeeze chute, four of the pens of heifers were sprinkle cooled and the remaining four pens were worked as normal. The heifers that were treated had a body temperature that peaked sooner (31.9pl0.63 min compared to 37.6pl0.62) with a lower peak body temperature (39.55pl0.03pC compared to 39.74pl0.03pC), and recovered sooner (70.5pl2.4 min compared to 83.2pl2.4 min). The treated animals also had a lower panting score, a visual assessment of level of cattle heat stress (1.1pl0.2 compared to 1.16pl0.2). The behavior measurements that were taken did not indicate a change in behavior. It was concluded that while a single instance of wetting an animal within the working facility did not completely offset the increase in body temperature, it was beneficial to the animals without needing to add water to the pen surface, thus reducing the potential for odor generation.