Use of Cool Drinking Water as a Strategy Under High-Ambient-Temperature Conditions in New Zealand Rabbits: Growth...

Heat stress represents a major challenge in rabbit production in tropical regions, where high temperature-humidity index (THI) values compromise thermal homeostasis and animal welfare. This study evaluated the effect of providing cool drinking water as a heat stress mitigation strategy on growth performance, carcass traits, water intake, and physiological responses in growing New Zealand White rabbits. Sixteen male rabbits were assigned to receive either drinking water at ambient temperature (33.9 ± 1.5 °C) or cooled water (16.7 ± 1.8 °C) supplied during periods of highest thermal load (10:00-17:00 h) over a four-week experimental period. Ambient temperature and relative humidity were monitored to calculate THI, and body temperatures were recorded during morning and afternoon periods. Average daily gain, carcass traits, and water intake were not affected by drinking water temperature (p > 0.05). However, the feed-to-gain ratio over the overall experimental period was higher in rabbits receiving cooled water (p = 0.03). In contrast, rectal temperature during the afternoon was significantly reduced in rabbits receiving cooled water, as reflected by a significant water × period interaction (p = 0.03), representing a 0.62% reduction compared with rabbits receiving normal drinking water, particularly during periods of greater thermal challenge, whereas ear and body surface temperatures were mainly influenced by the experimental period (p < 0.01). These results indicate that moderate cooling of drinking water elicits measurable physiological responses associated with short-term thermoregulatory adjustment, without improving growth performance. Providing cool drinking water represents a practical strategy to support thermoregulation under heat stress conditions in rabbit production systems in tropical climates.