# Use of Cool Drinking Water as a Strategy Under High-Ambient-Temperature Conditions in New Zealand Rabbits: Growth Performance, Carcass Traits and Physiological Responses

## TL;DR

Cool drinking water helps rabbits manage heat stress in tropical climates but doesn't improve growth or feed efficiency.

## Contribution

The study introduces moderate cooling of drinking water as a practical strategy for thermoregulation in heat-stressed rabbits.

## Key findings

- Cool water reduced afternoon body core temperature during peak heat stress.
- Cool water had no effect on daily weight gain, feed intake, or carcass traits.
- Feed-to-gain ratio was higher in rabbits receiving cooled water.

## Abstract

Rabbits raised in tropical climates are frequently exposed to high temperatures and humidity, which can compromise their ability to regulate body temperature and challenge thermal balance. Providing cool drinking water has been proposed as a simple management strategy to help animals cope with heat stress. In this study, growing rabbits were offered either drinking water at ambient temperature or moderately cooled water during the hottest hours of the day. While daily weight gain, feed intake, carcass traits, and water intake were not affected by water temperature, rabbits receiving cooled water showed lower body core temperature during the afternoon, when heat stress was greatest. However, the feed-to-gain ratio over the overall experimental period was higher in rabbits receiving cooled water. These responses indicate a localized thermoregulatory adjustment without clear productive advantages. These findings suggest that moderate cooling of drinking water can support thermoregulation under heat stress conditions in rabbit production systems in tropical environments.

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.