Move More Air
Calf housing should be positioned to utilize prevailing winds and should incorporate as many openings as possible to take advantage of natural air movement. Typically, open-faced buildings should face southeast. Hutches may be turned to face east in summer to maximize air movement and minimize solar heating.
Placing hutches 4 feet apart with 10 feet between rows allows air to circulate freely. Air movement can be enhanced by opening vents on hutches and placing a block under the back wall (be sure to maintain this opening as bedding builds up inside the hutch). In calf barns, fans can help keep calves cool and improve weight gains.
Depending on the facility, continual adjustments may be needed to keep ventilation adequate as weather changes occur, and automated controls can be very helpful. Greenhouse-type barns with transparent or translucent coverings will require more frequent adjustment than buildings with wooden or opaque roofs. Once temperatures reach 75°F, curtain sidewalls on calf barns should be completely open.
Offer Plenty of Water
As calves attempt to maintain their body temperature water is lost through increased respiration and evaporative cooling (sweating). In an Iowa study when the temperature exceeded 77°F calves increased water consumption independent of their grain intake (Quigley, 2011).
Whether calves are eating grain or not, they need to have access to water in hot weather. In addition, it may be critical to introduce each calf to water to insure they understand water is available. For scouring calves, early and aggressive use of fluid therapy is especially critical during hot weather; feed electrolytes at the first sign of scouring to help calves avoid dehydration.
Water buckets also may need to be filled more frequently (or switched to a larger size) in the summer, particularly for calves nearing weaning and those who have recently been weaned.
Keep Grain Fresh
Calves will naturally tend to eat less grain during periods of heat stress. This means efforts to encourage starter intake take on added importance. Offer only small handfuls at each feeding until calves begin to eat starter. Remove uneaten starter and clean out wet or moldy feed daily to maintain freshness. A divider between the grain bucket and water bucket can help keep starter fresh longer by limiting the amount of transfer between the two buckets.
Consider Inorganic Bedding
Inorganic bedding is preferred by some calf raisers as it helps keep calves cooler by absorbing body heat and dissipating it, rather than retaining it. Regardless of the material used for bedding, the priority should be to provide a clean, dry area for calves to rest.