A 2011 trial done at Washington State University by Dale Moore and colleagues Jen Duprau and John Wenz showed that elevating one side of the hutch decreased internal hutch temperature and increased ventilation in warm weather.
Hutches were elevated with an 8 X 8 X 16-inch concrete block, and temperature and humidity data loggers were used to take hourly measurements.
- Calf respiratory rate was higher with higher internal hutch temperature. For every 1⁰C increase in internal hutch temperature, respiratory rate increased by 2 breaths per minute.
- At the hottest times of the day, internal hutch temperatures were higher than outside temperatures when the hutch was on the ground. Internal hutch temperatures were lower than outside when the hutch was elevated.
- Elevating the hutch improved air movement within the hutch.
- Hutch elevation lowered afternoon respiratory rates in the calves -- 58 versus 44 breaths per minute.
- Hutch carbon dioxide levels were lower when the hutch was elevated.
Calf respiratory rate can indicate a level of heat stress. In the late afternoon, elevating the hutch lowered the temperature and subsequently, the respiratory rates of the calves. Decreasing carbon dioxide levels within the hutches is important because the concentration of this gas is associated with poor ventilation. The evidence for internal air movement is also an indication of better ventilation from elevating the hutch. Improving ventilation and reducing heat are both important to calf health and welfare. Dairy producers now have another validated choice to remediate summer heat stress in calves.
Read more about calf ventilation, heat stress and this study here.