Calf hutches offer many advantages for raising preweaned dairy calves, but unfortunately they lack the climate-control features possible in larger barns. In the heat of summer, that can result in a greater likelihood of calves experiencing heat stress.
Penn State University Dairy Extension educators Jud Heinrichs and Colleen Jones say high temperatures, excessive humidity and the hot sun can take a toll on calves. Other factors that come into play are air movement, moisture, hair coat, bedding source and rumination activity.
Calves under heat stress might have reduced feed intake, increased maintenance energy needs and lower immunity. The result can be impaired growth, higher susceptibility to disease and even death. Research shows that, like adult cows, calves experience more heat stress in periods with no night cooling.
Heinrichs and Jones offer the following research-based suggestions for managing hutches for heat abatement:
1.) Provide shade. Installing 80% shade cloth 3' to 4' above hutches has been shown to reduce air temperature inside hutches by 3°F to 4°F. Even situating hutches among shade trees can help.
2.) Allow calves to move around. Calves confined to hutches might be at greater risk of heat stress than those that are able to choose where they rest.Outdoor pens or tethers allow calves more freedom to select a comfortable spot.
3.) Face hutches east. In the summer, opening hutches to the east should maximize air movement and minimize solar heating. A spacing of 4' between hutches and 10' between rows is advised to allow air to circulate freely.
4.) Elevate hutches. Several research studies have proven advantages to elevating hutches in hot weather. One way to do this is to prop up the back of the hutch with concrete blocks. Advantages to elevating hutches include increased airflow, lower temperature inside the hutch, reduced calf respiratory rates and lower airborne bacteria levels inside the hutch.
5.) Provide free-choice water. Delivering water to calves in hutches usually is a manual process, but an important one. Water aids in digestion and replaces body hydration that calves lose through sweating. If calves are scouring and no water is available, they are extremely vulnerable to heat stress.
6.) Offer fresh starter grain. Warm, moist conditions in summer cause starter grain to spoil faster. Calves are also prone to eating less grain during periods of heat stress. Offer grain in smaller quantities, replace it daily and place a divider between the grain bucket and water bucket to keep the starter fresh longer.